Tailored cyclodepsipeptides as potent non-covalent serine protease inhibitors

Abstract

The present invention pertains to an improved chemical synthesis method for Ahp-cyclodepsipeptides which allows straight forward and easy synthesis of tailor-made Ahp-cyclodepsipeptides. The invention further provides Ahp-cyclodepsipeptides for use as HTRA protease inhibitors and their medical use.

Claims

1. A method for synthesizing an Ahp-cyclodepsipeptide, comprising the steps of (a) providing a resin loaded with 5-hydroxy-norvaline, named amino acid P1′, wherein the 5-hydroxy-norvaline P1′ is coupled to the resin via its 5-hydroxyl group forming an ether bond with the resin; (b) adding 2 to 6 amino acids, named amino acid P1 to P6, to the 5-hydroxy-norvaline P1′ using N terminal peptide synthesis, wherein the second amino acid P2 is an amino acid with a hydroxyl group in the side chain; (c) adding an amino acid, named Px, to the hydroxyl group of the amino acid P2 via esterification with the α-carboxylic acid group of the amino acid; (d) adding an N-methylated amino acid, named P3′, to the amino acid Px added in step (c) using N terminal peptide synthesis; (e) adding an amino acid, named P2′, to the methylated amino group of the amino acid P3′ added in step (d); (f) forming a peptide pond between the α-carboxylic acid group of the 5-hydroxy-norvaline P1′ and the α-amino group of the amino acid P2′ added in step (e), thereby cyclizing the formed peptide; (g) cleaving the cyclic peptide from the resin; (h) oxidizing the peptide so that the 5-hydroxy-norvaline P1′ and the amino acid P2′ added in step (e) form a 3-amino-6-hydroxy-2-piperidone unit, thereby providing an Ahp-cyclodepsipeptide.

2. The method according to claim 1, wherein the resin is a chlorotrityl resin.

3. The method according to claim 1, wherein the peptide is cleaved from the resin in step (g) using an acid.

4. The method according to claim 1, wherein the side chains of the amino acids added in steps (b), (c), (d) and (e) and the presence or absence of amino acids P3 to P6 in step (b) are selected for binding to a target serine protease.

5. The method according to claim 1, wherein the N-methylated amino acid P3′ added in step (d) is an aromatic amino acid, and/or wherein the amino acid P2 comprising a hydroxyl group in its side chain is selected from threonine, (3-OH)-phenylalanine and (3-OH)-leucine.

6. The method according to claim 3, wherein the acid is trifluoroacetic acid.

7. The method according to claim 5, wherein the N-methylated amino acid P3′ added in step (d) is phenylalanine or tyrosine.

Description

FIGURES

(1) FIG. 1 shows the chemical structure of and its corresponding binding mode.

(2) FIG. 2 shows the cell-based evaluation of HTRA1 inhibition potency of Ahp10. Alizarin Red S staining of HTRA1-mediated biomineralization of mesenchymal stem cells in absence or presence of 10 μM Ahp10 as well as HTRA1 or a catalytically inactive mutant HTRA1SA. Error bars indicate standard deviation of three independent measurements.

EXAMPLES

Example 1: Chemical Synthesis of Ahp-Cyclodepsipeptides

(3) 1. General Information

(4) Reagents

(5) All reagents were purchased from Iris Biotech, Biosolve Chemicals, Carbolution Chemicals, ABCR, Novabiochem, Sigma Aldrich, TCI Chemicals, Bernd Kraft or VWR Chemicals and were used without further purification.

(6) Reversed-Phase Liquid Chromatography Electrospray Ionization Mass Spectrometry (LC-MS)

(7) Reaction control analyses were performed on a LC-MS system from Thermo Scientific. The system consisted of a Thermo Scientific Accela (peak detection at 210 nm) equipped with an Eclipse XDB-C18 5 μm column (both from Agilent) and a Thermo Scientific LCQ Fleet ESI-MS. For analysis, a linear gradient of solvent B (0.1% formic acid in acetonitrile) in solvent A (0.1% formic acid in water) at flow rate of 1 mL min.sup.−1 and the following gradient program: 0 min./10% B.fwdarw.1 min./10% B.fwdarw.10 min./100% B.fwdarw.12 min./100% B.fwdarw.15 min./10% B was used.

(8) Preparative Reversed-Phase High Performance Liquid Chromatography (Prep HPLC)

(9) Compound purification was achieved by preparative reversed-phase HPLC using the Prominence UFLC system from Shimadzu (peak detection at 210 nm). The system was equipped with a reversed-phase column Luna® 5 μm C18(2), 100×21.20 mm. A linear gradient acetonitrile in water (0.1% TFA) at a flow rate of 25 mL min.sup.−1 was used that adapted for each purification application.

(10) Nuclear Magnetic Resonance Spectroscopy (NMR)

(11) Nuclear magnetic resonance (NMR) spectra were recorded on an Avance II 400 (400 MHz for .sup.1H- and 100 MHz for .sup.13C-NMR) or an Avance II 700 (400 MHz for .sup.1H- and 176 MHz for .sup.13C-NMR) machine. .sup.1H NMR spectra are reported in the following manner: chemical shifts (δ) in ppm calculated with reference to the residual signals of undeuterated solvent, multiplicity (s, singlet; d, doublet; t, triplet; dd, doublet of doublet; dt, doublet of triplet; td, triplet of doublet; m, multiplet), coupling constants (J) in Hertz (Hz), and number of protons (H).

(12) 2. Synthesis of Solid Phase Building Block

Synthesis of N-(9-Fluorenylmethoxycarbonyl)-(L)-5-hydroxy-norvaline-1-allyl ester (SI-1)

(13) ##STR00012##

(14) N-(9-FluorenylmethoxycarbonyI)-(L)-glutamic acid-1-allyl ester (1.00 g, 2.44 mmol, 1 eq) was dissolved in anhydrous THF (150 mL) under an argon atmosphere. Triethyl amine (1.01 mL, 7.33 mmol, 3 eq) and isobutyl chloroformiate (1.26 mL, 9.77 mmol, 4 eq) were added at room temperature. The resulting suspension was stirred for 15 minutes. Sodium borohydride (557 mg, 14.66 mmol, 6 eq) was dissolved in water (50 mL) and was slowly added. The resulting slightly cloudy solution was stirred for further 15 min. The reaction was quenched by addition of 1 M aq. potassium hydrogen sulfate solution (50 mL) and the product was extracted with DCM (3×100 mL). The combined organic phases were dried over magnesium sulfate and the crude product was purified by flash column chromatography (ethyl acetate:cyclohexane (1:1).fwdarw.dichloromethane:methanol (50:1)).

(15) Yield: 695 mg (1.76 mmol, 72%) as white solid.

(16) TLC (ethyl acetate:cyclohexane (1:1)): R.sub.f=0.33; LC-MS (ESI): t.sub.R=8.65 min; m/z=395.8 [M+H].sup.+, 418.1 [M+Na].sup.+, 377.7 [M+H—OH].sup.+, 337.7 [M+H—OAII].sup.+, calcd. for C.sub.23H.sub.25NO.sub.5: 395.17.

(17) .sup.1H NMR (400 MHz, DMSO-d6) δ 7.90 (d, J=7.5 Hz, 2H), 7.83 (d, J=7.8 Hz, 1H), 7.73 (dd, J=7.4, 2.2 Hz, 2H), 7.42 (t, J=7.4 Hz, 2H), 7.34 (t, J=7.4 Hz, 2H), 5.95-5.85 (m, 1H), 5.31 (dq, J=17.3, 1.8 Hz, 1H), 5.21 (dt, J=10.5, 1.6 Hz, 1H), 4.59 (d, J=5.3 Hz, 2H), 4.52-4.41 (m, 1H), 4.36-4.17 (m, 3H), 4.13-4.04 (m, 1H), 3.40 (tt, J=6.4, 3.1 Hz, 2H), 1.85-1.77 (m, 1H), 1.70-1.61 (m, 1H), 1.57-1.40 (m, 2H).

(18) .sup.13C NMR (101 MHz, DMSO) δ 172.14, 156.12, 143.79, 140.70, 132.38, 127.61, 127.03, 125.23, 120.09, 117.66, 65.64, 64.69, 60.00, 53.81, 46.62, 28.83, 27.44.

(19) 3. General Methods for Solid Phase Synthesis

(20) Method A: Resin Loading

(21) N-(9-Fluorenylmethoxycarbonyl)-(L)-5-hydroxy-norvaline-1-allyl ester (103 mg, 0.26 μmol, 1 eq) was dissolved in anhydrous DCM and pyridine (63 μL, 0.78 mmol, 3 eq) was added. The loading solution was added under inert gas to a chlorotrityl resin (1 g, max. loading: 1.6 mmol g.sup.−1) and the resulting suspension was gently shaken for 72 h. The solution was removed and the resin was washed with DMF (2×1 min). The resin was washing with a DCM/MeOH/DIPEA (85:10:5, 3×15 min.) solution. The resin was washed with DMF (3×1 min) and DCM (3×1 min).

(22) Method B: Determination of Loading Efficiency

(23) An aliquot of the loaded resin (˜10 mg) was treated with freshly prepared 20% piperidine/DMF solution (5 mL) for 20 min. The solution was separated from the resin and the UV absorption of the solution was measured at a wavelength of 301 nm by a UV spectrophotometer. The loading was determined from the measured parameters via the following equation: β=A.Math.V/ε.Math.d.Math.m.Math.F [mmol/g]

(24) A is the absorption at 301 nm, V the total volume, ε the extinction coefficient of cleaved Fmoc, d the thickness of the cuvette, m the mass of the resin and F the dilution factor (1 unless further dilutions were taken).

(25) Method C: Amino Acid Coupling

(26) The amino acid (4 eq) and HBTU (4 eq) were dissolved in 0.2 M HOBt in DMF (5.5 mL). This solution and DIPEA (4 eq) were added to the resin and the resulting suspension was shaken for 45 min. The solution was separated from the resin was washed with DMF (3×1 min).

(27) Method D: Fmoc Deprotection

(28) A solution of 40% piperidine in DMF (6 mL) was added to resin and the resulting suspension was shaken for 3 min. The piperidine solution was removed and resin was treated with 20% piperidine in DMF for another 12 min (6 mL). The deprotection solution was removed and the resin was washed with DMF (6×1 min).

(29) Method E: Esterification

(30) The corresponding amino acid (10 eq) was dissolved in DCM (4 mL) and DIPEA (10 eq) was added. DMAP (0.5 eq) was dissolved in DCM (0.75 mL) and both solutions and DIC (10 eq) were added to the resin and the resulting suspension was shaken for 60 min at 40° C. The solution was removed and the resin was washed with DCM (3×1 min). The whole esterification procedure was repeated four more times. The resin was washed with DMF (5×1 min).

(31) Method F: Amino Acid Coupling on Methylated Amino Groups

(32) PyBrop (4 eq) and amino acid (4 eq) was dissolved in DCM (5 mL). The resulting solution and DIPEA (4 eq) were added to the resin. The resulting suspension was shaken for 60 min at 40° C. The solution was discarded and the resin was washed with DCM (3×1 min). The procedure was repeated five times. The resin was washed with DMF (5×1 min).

(33) Method G: Allyl Deprotection

(34) The resin was washed five times with anhydrous DCM under inert gas and a solution of tetrakis(triphenylphosphine)palladium(0) (0.5 eq) and morpholine (24 eq) in anhydrous DCM (5.5 mL) was added. The resulting suspension was shaken for two hours.

(35) The solution was removed and the resin was washed with DCM (3×1 min), DMF (3×1 min) and NMP (3×1 min). The procedure was completed by washing steps with a 0.02 M solution of Et2NCS2Na in NMP (3×5 min), NMP (3×1 min), DMF (3×1 min) and DCM (3×1 min).

(36) Method H: Peptide Cyclization

(37) HBTU (4 eq), HOBt (4 eq) and DIPEA (4 eq) were dissolved in DMF (5 mL). The solution was added to the resin and the resulting suspension was shaken overnight. The cyclization solution was removed and the resin was washed with DMF (3×1 min), NMP (3×1 min), DMF (3×1 min) and DCM (3×1 min).

(38) Method I: Cleavage from Resin

(39) The resin was treated with a solution of TFA/triisopropylsilane/H2O (95:2.5:2.5, 9 mL) for 2 h. The cleavage solution was transferred in a flask and the resin was washed with DCM (3×1 min). All solutions were combined in the flask. From the resulting solution, DCM was evaporated and TFA was co-evaporated with toluene under reduce pressure to dryness. The residue was dried at high vacuum.

(40) Method J: Dess-Martin Oxidation

(41) The purified Ahp-cyclodepsipeptide precursor (1 eq) was dissolved in DCM (10 mL) and Dess-Martin periodinane (1.5 eq) was added. The slightly turbid solution was stirred for 1 h. The solution was evaporated under reduce pressure and the residue was dissolved in acetonitrile/water (1:1, 5 mL) and stirred overnight.

(42) 4. General Synthesis Procedure for Ahp-Cyclodepsipeptides

(43) Fmoc-Hnv-OAII was loaded on chlorotrityl resin according to method A. The resin loading was determined using method B (β=0.2 mmol g−1). 1000 mg resin (0.2 mmol) were used for synthesis. The first four amino acids were coupled by alternatingly using method C and method D for Fmoc deprotection. This step was followed by the esterification with a Fmoc-protected amino acid using method E. The Fmoc group was cleaved (method D) and the Fmoc-protected and N-methylated amino acid was coupled (method C). Fmoc deprotection (method D) delivered the starting material for coupling of the last amino acid via method F, followed by Fmoc deprotection (method D). The allyl ester was cleaved with method G. The peptide was cyclized using method H and was cleaved according to method I. The crude product was purified by preparative reversed-phase HPLC. The residue was oxidized according to method J, followed by an HPLC purification, thereby delivering the desired Ahp-cyclodepsipeptide.

Example 2: Synthesis of Specific Ahp-Cyclodepsipeptides

(44) ##STR00013##

(45) Ahp1 (18) was synthesized via the ‘general synthesis procedure for Ahp-cyclodepsipeptides’.

(46) Yield: 9.9 mg (10.3 μmol, 5.2%) as a white solid.

(47) .sup.1H NMR (400 MHz, DMSO-d6): δ 8.18 (d, J=9.4 Hz, 1H), 8.04 (d, J=7.8 Hz, 1H), 7.87 (d, J=9.6 Hz, 1H), 7.51-7.10 (m, 12H), 5.98 (t, J=1.7 Hz, 1H), 5.65-5.55 (m, 1H), 5.08-5.02 (m, 3H), 4.89 (s, 1H), 4.78-4.70 (m, 2H), 4.61-4.51 (m, 1H), 4.52-4.43 (m, 1H), 4.44-4.34 (m, 1H), 4.29 (dd, J=9.5, 4.0 Hz, 1H), 4.08 (p, J=7.2 Hz, 1H), 2.92-2.74 (m, 1H), 2.74 (s, 3H), 2.55 (t, J=5.6 Hz, 1H), 2.21-2.16 (m, 1H), 2.12-2.03 (m, 1H), 1.75-1.72 (m, 3H), 1.60-1.42 (m, 1H), 1.26-1.19 (m, 12H), 0.87 (dd, J=6.7, 5.2 Hz, 3H), 0.85-0.75 (m, 6H), 0.74 (d, J=6.9 Hz, 3H), 0.67 (d, J=6.6 Hz, 3H), 0.43 (d, J=6.5 Hz, 3H), 0.33-0.21 (m, 1H).

(48) LC-MS (ESI): t.sub.R=8.27 min; m/z=962.8 [M+H].sup.+, 945.0 [M+H—H.sub.2O].sup.+, 985.4 [M+Na].sup.+, calcd. for C.sub.49H.sub.70N.sub.8O.sub.12: 962.51.

(49) ##STR00014##

(50) Ahp2 (19) was synthesized via the ‘general synthesis procedure for Ahp-cyclodepsipeptides’.

(51) Yield: 1.1 mg (1.1 μmol, 0.6%) as a white solid.

(52) .sup.1H NMR (700 MHz, DMSO-d6): δ 8.86 (d, J=9.6 Hz, 1H), 8.51 (d, J=4.1 Hz, 1H), 8.49 (d, J=7.5 Hz, 1H), 8.34 (d, J=9.6 Hz, 1H), 7.33-7.03 (m, 17H), 5.60 (d, J=5.4 Hz, 1H), 5.43 (t, J=5.3 Hz, 1H), 5.09-5.06 (m, 1H), 4.89 (s, 2H), 4.65 (dd, J=9.7, 3.3 Hz, 1H), 4.58-4.3 (m, 1H), 4.51-4.41 (m, 3H), 4.30-4.24 (m, 2H), 4.04 (q, J=7.1 Hz, 1H), 3.81 (dd, J=14.1, 2.8 Hz, 1H), 2.91-2.85 (m, 1H), 2.83 (dd, J=14.1, 5.0 Hz, 1H), 2.74 (s, 3H), 2.62-2.57 (m, 1H), 2.33-2.25 (m, 1H), 1.80-1.76 (m, 1H), 1.68-1.60 (m, 1H), 1.54-1.44 (m, 2H), 1.18 (dd, J=7.2, 2.6 Hz, 6H), 1.02 (d, J=6.2 Hz, 3H), 0.93 (td, J=14.0, 13.5, 3.3 Hz, 1H), 0.88-0.82 (m, 1H), 0.79 (d, J=6.9 Hz, 3H), 0.69 (dd, J=9.1, 6.7 Hz, 6H), 0.62 (d, J=6.7 Hz, 3H), −0.67 (t, J=12.4 Hz, 1H).

(53) .sup.13C NMR (176 MHz, DMSO-d6): δ 202.86, 173.87, 173.51, 172.11, 171.71, 171.64, 171.04, 170.80, 169.90, 166.46, 155.85, 139.40, 137.45, 137.34, 130.39, 129.32, 129.12, 128.52, 127.90, 127.55, 126.80, 80.43, 73.69, 65.83, 62.86, 60.22, 58.87, 56.09, 55.38, 53.87, 50.95, 49.66, 47.61, 47.37, 37.45, 33.74, 31.39, 30.05, 29.21, 26.81, 23.86, 23.77, 21.24, 20.08, 19.97, 19.83, 17.24, 16.42, 15.40, 14.56, 1.63.

(54) LC-MS (ESI): t.sub.R=8.77 min; m/z=1011.6 [M+H].sup.+, 993.0 [M+H+—H.sub.2O].sup.+, 1033.4 [M+Na].sup.+, calcd. for C.sub.53H.sub.70N.sub.8O.sub.12: 1010.51.

(55) ##STR00015##

(56) Ahp3 (20) was synthesized via the ‘general synthesis procedure for Ahp-cyclodepsipeptides’.

(57) Yield: 1.0 mg (1.0 μmol, 0.5%) as a white solid.

(58) .sup.1H NMR (400 MHz, DMSO-d6): δ 8.90 (d, J=9.6 Hz, 1H), 8.46 (d, J=3.9 Hz, 1H), 8.39 (d, J=9.6 Hz, 1H), 7.98 (d, J=7.6 Hz, 1H), 7.41 (d, J=9.8 Hz, 1H), 7.37-7.18 (m, 16H), 6.14 (d, J=2.4 Hz, 1H), 5.67 (d, J=5.4 Hz, 1H), 5.47 (t, J=5.0 Hz, 1H), 5.03-4.96 (m, 2H), 4.95-4.87 (m, 2H), 4.82-4.77 (m, 2H), 4.59-4.53 (m, 1H), 4.49-4.39 (m, 2H), 4.20-4.08 (m, 2H), 3.73-3.62 (m, 1H), 3.04-2.91 (m, 1H), 2.78 (s, 3H), 2.46-2.19 (m, 1H), 1.84-1.74 (m, 2H), 1.69-1.45 (m, 2H), 1.25 (d, J=6.9 Hz, 4H), 1.16 (d, J=7.0 Hz, 3H), 0.93 (t, J=11.8 Hz, 1H), 0.86 (d, J=6.6 Hz, 3H), 0.81 (t, J=6.9 Hz, 6H), 0.74 (dd, J=13.2, 6.7 Hz, 6H), 0.61 (d, J=6.5 Hz, 3H), −0.61 (t, J=12.4 Hz, 1H).

(59) .sup.13C NMR (101 MHz, DMSO-d6): δ 173.05, 172.44, 172.32, 171.24, 170.94, 169.90, 169.31, 165.80, 159.85, 138.86, 137.61, 136.88, 129.80, 128.60, 128.31, 128.18, 127.76, 127.58, 127.42, 126.44, 125.57, 80.07, 72.34, 68.65, 65.38, 62.49, 58.13, 55.44, 54.98, 54.19, 47.26, 47.05, 31.86, 29.63, 28.77, 28.66, 25.83, 23.15, 19.46, 19.38, 18.94, 18.62, 18.45, 17.03, 16.85.

(60) LC-MS (ESI): t.sub.R=8.82 min; m/z=1025.3 [M+H].sup.+, 1007.2 [M+H—H.sub.2O].sup.+, 1047.6 [M+Na].sup.+, calcd. for C.sub.54H.sub.72N.sub.8O.sub.12: 1024.53.

(61) ##STR00016##

(62) Ahp4 (21) was synthesized via the ‘general synthesis procedure for Ahp-cyclodepsipeptides’.

(63) Yield: 1.4 mg (1.3 μmol, 0.7%) as a white solid.

(64) .sup.1H NMR (700 MHz, DMSO-d6): δ 8.83 (d, J=9.6 Hz, 1H), 8.43 (d, J=4.1 Hz, 1H), 8.33 (d, J=8.2 Hz, 1H), 8.07 (d, J=9.8 Hz, 1H), 7.50 (d, J=9.9 Hz, 1H), 7.41-7.01 (m, 16H), 5.67 (d, J=5.4 Hz, 1H), 5.44 (t, J=5.4 Hz, 1H), 5.17 (qd, J=6.2, 1.9 Hz, 1H), 4.93 (s, 2H), 4.88-4.84 (m, 2H), 4.69 (dd, J=9.7, 3.3 Hz, 1H), 4.59 (dd, J=9.8, 2.0 Hz, 1H), 4.50-4.42 (m, 2H), 4.18-4.11 (m, 1H), 4.09-4.05 (m, 1H), 3.64-3.59 (m, 1H), 3.22 (dd, J=14.4, 4.8 Hz, 1H), 2.92-2.82 (m, 1H), 2.80 (dd, J=14.5, 9.5 Hz, 1H), 2.73 (s, 3H), 2.39-2.28 (m, 1H), 1.81-1.79 (m, 1H), 1.76-1.70 (m, 1H), 1.62-1.57 (m, 1H), 1.50-1.47 (m, 1H), 1.24 (s, 2H), 1.14 (d, J=7.2 Hz, 3H), 1.11 (d, J=6.2 Hz, 3H), 0.84 (d, J=6.7 Hz, 4H), 0.79 (dd, J=13.8, 6.8 Hz, 6H), 0.73 (d, J=6.6 Hz, 3H), 0.70 (d, J=6.8 Hz, 3H), 0.57 (d, J=6.6 Hz, 4H), −0.69 (t, J=12.3 Hz, 1H).

(65) .sup.13C NMR (176 MHz, DMSO-d6): δ 173.04, 171.33, 171.25, 171.03, 170.90, 170.25, 169.74, 166.36, 155.31, 138.81, 137.98, 136.94, 129.86, 129.16, 128.55, 128.19, 127.98, 127.56, 127.25, 79.98, 72.69, 65.34, 62.43, 58.28, 55.62, 54.93, 54.71, 53.97, 52.61, 49.57, 47.17, 39.53, 37.11, 35.49, 33.27, 31.72, 30.89, 29.58, 28.84, 28.76, 23.41, 23.22, 19.52, 19.45, 19.37, 18.63, 18.40, 16.83, 16.20.

(66) LC-MS (ESI): t.sub.R=7.47 min; m/z=1039.2 [M+H].sup.+, 1021.1 [M+H—H.sub.2O].sup.+, 1061.5 [M+Na].sup.+, calcd. for C.sub.55H.sub.74N.sub.8O.sub.12: 1038.54.

(67) ##STR00017##

(68) Ahp5 (22) was synthesized via the ‘general synthesis procedure for Ahp-cyclodepsipeptides’.

(69) Yield: 2.1 mg (2.0 μmol, 1.0%) as a white solid.

(70) .sup.1H NMR (700 MHz, DMSO-d6): δ 8.98 (d, J=9.6 Hz, 1H), 8.80 (d, J=7.5 Hz, 1H), 8.49 (d, J=4.1 Hz, 1H), 8.10 (d, J=9.7 Hz, 1H), 7.43-6.89 (m, 17H), 5.68 (d, J=5.4 Hz, 1H), 5.45 (t, J=5.3 Hz, 1H), 5.12-5.09 (m, 1H), 4.96 (dd, J=11.6, 3.0 Hz, 1H), 4.76 (d, J=2.8 Hz, 2H), 4.63 (dd, J=9.8, 1.7 Hz, 1H), 4.58 (q, J=7.3 Hz, 1H), 4.55-4.51 (m, 1H), 4.45 (d, J=9.4 Hz, 2H), 4.08 (dd, J=9.7, 8.0 Hz, 1H), 3.86 (dd, J=14.1, 2.7 Hz, 1H), 3.39 (q, J=7.0 Hz, 2H), 2.96-2.90 (m, 2H), 2.78 (s, 3H), 2.65-2.59 (m, 1H), 2.34-2.30 (m, 1H), 1.81-1.78 (m, 1H), 1.76-1.70 (m, 1H), 1.68-1.62 (m, 1H), 1.58-1.51 (m, 1H), 1.50-1.48 (m, 1H), 1.30 (d, J=7.0 Hz, 3H), 1.10 (t, J=7.0 Hz, 3H), 1.05 (d, J=6.2 Hz, 3H), 0.96-0.90 (m, 1H), 0.87-0.80 (m, 6H), 0.77 (d, J=6.7 Hz, 3H), 0.71 (d, J=6.8 Hz, 3H), 0.63 (d, J=6.7 Hz, 3H), −0.57-−0.67 (m, 1H).

(71) .sup.13C NMR (176 MHz, DMSO-d6): δ 173.52, 173.11, 172.35, 171.77, 171.32, 169.89, 166.82, 156.05, 139.35, 138.42, 137.17, 130.41, 129.51, 129.17, 128.71, 128.46, 127.83, 127.42, 80.51, 73.80, 65.76, 65.38, 62.94, 58.67, 56.32, 55.95, 55.18, 54.00, 47.60, 32.07, 30.13, 29.32, 29.20, 23.95, 23.70, 20.19, 19.89, 19.13, 18.82, 17.22, 16.64, 15.64, 15.54.

(72) LC-MS (ESI): t.sub.R=9.40 min; m/z=1039.0 [M+H].sup.+, 1021.0 [M+H—H.sub.2O].sup.+, 1061.4 [M+Na].sup.+, calcd. for C.sub.55H.sub.74N.sub.8O.sub.12: 1038.54.

(73) ##STR00018##

(74) Ahp6 (23) was synthesized via the ‘general synthesis procedure for Ahp-cyclodepsipeptides’.

(75) Yield: 2.6 mg (2.6 μmol, 1.3%) as a white solid.

(76) .sup.1H NMR (700 MHz, DMSO-d6): δ 8.80 (d, J=9.8 Hz, 1H), 8.50 (d, J=3.6 Hz, 1H), 8.43 (d, J=7.4 Hz, 1H), 8.09 (d, J=9.8 Hz, 1H), 7.63 (d, J=9.8 Hz, 1H), 7.36 (d, J=9.1 Hz, 1H), 7.28-7.10 (m, 15H), 5.64 (d, J=5.5 Hz, 1H), 5.42 (t, J=5.3 Hz, 1H), 5.14-5.10 (m, 2H), 5.00 (d, J=12.4 Hz, 1H), 4.96-4.88 (m, 2H), 4.71-4.66 (m, 2H), 4.60 (q, J=7.2 Hz, 1H), 4.29 (d, J=9.2 Hz, 1H), 4.24 (p, J=7.4 Hz, 1H), 3.98 (dd, J=9.7, 7.5 Hz, 1H), 3.86 (d, J=13.7 Hz, 1H), 2.90 (t, J=12.8 Hz, 1H), 2.78 (s, 3H), 2.33-2.27 (m, 1H), 2.21-2.17 (m, 2H), 2.04-1.95 (m, 1H), 1.73-1.71 (m, 1H), 1.67-1.63 (m, 1H), 1.52-1.49 (m, 1H), 1.47-1.45 (m, 1H), 1.26 (d, J=7.1 Hz, 3H), 1.21 (d, J=7.3 Hz, 3H), 1.10 (d, J=6.2 Hz, 3H), 0.81 (d, J=6.9 Hz, 3H), 0.74-0.70 (m, 9H).

(77) LC-MS (ESI): t.sub.R=8.58 min; m/z=997.1 [M+H].sup.+, 979.0 [M+H—H.sub.2O].sup.+, 1019.5 [M+Na].sup.+, calcd. for C.sub.52H.sub.68N.sub.8O.sub.12: 996.50.

(78) ##STR00019##

(79) Ahp7 (24) was synthesized via the ‘general synthesis procedure for Ahp-cyclodepsipeptides’.

(80) Yield: 1.9 mg (2.1 μmol, 1.1%) as a white solid.

(81) .sup.1H NMR (400 MHz, DMSO-d6): δ 8.74 (d, J=3.7 Hz, 1H), 8.55 (d, J=9.7 Hz, 1H), 8.40 (d, J=7.4 Hz, 1H), 8.09 (d, J=9.6 Hz, 1H), 7.37-7.28 (m, 6H), 7.25 (d, J=9.2 Hz, 1H), 5.69 (d, J=5.4 Hz, 1H), 5.46 (t, J=5.2 Hz, 1H), 5.10-5.06 (m, 1H), 5.02 (d, J=3.3 Hz, 3H), 4.94-4.87 (m, 1H), 4.61-4.32 (m, 4H), 4.29-3.99 (m, 3H), 2.56 (s, 3H), 1.94-1.74 (m, 2H), 1.70-1.47 (m, 2H), 1.39 (d, J=6.6 Hz, 3H), 1.23 (d, J=5.4 Hz, 3H), 1.20-1.10 (m, 5H), 1.04 (t, J=6.2 Hz, 7H), 0.98 (d, J=6.6 Hz, 3H), 0.91-0.85 (m, 4H), 0.84-0.71 (m, 6H), 0.68 (d, J=6.8 Hz, 3H).

(82) LC-MS (ESI): t.sub.R=7.47 min; m/z=887.1 [M+H].sup.+, 869.1 [M+H—H.sub.2O].sup.+, 909.5 [M+Na].sup.+, calcd. for C.sub.43H.sub.66N.sub.8O.sub.12: 886.48.

(83) ##STR00020##

(84) Ahp8 (25) was synthesized via the ‘general synthesis procedure for Ahp-cyclodepsipeptides’.

(85) Yield: 13.2 mg (13.1 μmol, 6.6%) as a white solid.

(86) .sup.1H NMR (700 MHz, DMSO-d6): δ 9.23 (d, J=9.5 Hz, 1H), 8.59 (d, J=3.8 Hz, 1H), 8.46 (d, J=7.4 Hz, 1H), 8.13 (d, J=9.8 Hz, 1H), 7.47 (d, J=9.8 Hz, 1H), 7.38-7.04 (m, 16H), 5.74 (d, J=5.5 Hz, 1H), 5.61 (t, J=5.4 Hz, 1H), 5.16-5. (m, 1H), 4.93-4.86 (m, 3H), 4.71 (dd, J=11.5, 3.2 Hz, 1H), 4.65 (dd, J=9.8, 2.1 Hz, 1H), 4.56-4.50 (m, 3H), 4.27-4.20 (m, 1H), 4.17-4.13 (m, 1H), 3.71-3.65 (m, 1H), 2.67-2.60 (m, 1H), 2.51 (s, 3H) 1.90-1.86 (m, 1H), 1.82-1.72 (m, 1H), 1.66-1.62 (m, 2H), 1.40 (d, J=3.9 Hz, 3H), 1.24 (d, J=6.7 Hz, 3H), 1.21 (d, J=7.3 Hz, 2H), 1.11 (d, J=6.1 Hz, 3H), 0.93 (t, J=13.1 Hz, 1H), 0.85 (d, J=6.7 Hz, 3H), 0.78-0.76 (m, 8H), 0.61 (d, J=6.7 Hz, 3H), −0.53 (dd, J=18.5, 6.5 Hz, 1H).

(87) .sup.13C NMR (176 MHz, DMSO-d6): δ 173.24, 172.38, 171.91, 171.77, 171.05, 170.51, 170.33, 169.51, 166.44, 155.35, 138.97, 137.71, 136.90, 129.70, 128.96, 128.55, 128.21, 128.07, 127.44, 127.12, 118.08, 80.26, 73.55, 65.31, 62.48, 59.75, 58.37, 54.92, 54.71, 53.70, 51.85, 49.32, 47.26, 47.02, 37.74, 36.65, 32.49, 31.69, 31.28, 28.85, 28.24, 26.34, 23.50, 23.29, 20.77, 19.68, 19.52, 18.71, 18.25, 15.99, 15.45, 14.09, 1.16.

(88) LC-MS (ESI): t.sub.R=8.76 min; m/z=1011.2 [M+H].sup.+, 993.1 [M+H—H.sub.2O].sup.+, 1033.1 [M+Na].sup.+, calcd. for C.sub.53H.sub.70N.sub.8O.sub.12: 1010.51.

(89) ##STR00021##

(90) Ahp9 (26) was synthesized via the ‘general synthesis procedure for Ahp-cyclodepsipeptides’.

(91) Yield: 11.8 mg (12.1 μmol, 6.1%) as a white solid.

(92) .sup.1H NMR (400 MHz, DMSO-d6): δ 8.84 (d, J=9.7 Hz, 1H), 8.54 (d, J=4.1 Hz, 1H), 8.48 (d, J=7.5 Hz, 1H), 8.11 (d, J=9.6 Hz, 1H), 7.41 (d, J=9.9 Hz, 1H), 7.38-7.03 (m, 11H), 5.70-5.48 (m, 1H), 5.45-5.36 (m, 1H), 5.09 (dt, J=7.9, 5.6 Hz, 1H), 4.90 (s, 3H), 4.67 (dd, J=9.7, 3.2 Hz, 1H), 4.58-4.48 (m, 3H), 4.40-4.21 (m, 3H), 3.84-3.72 (m, 1H), 2.94-2.87 (m, 1H), 2.75 (s, 3H), 2.45-2.24 (m, 2H), 1.88-1.78 (m, 1H), 1.65-1.55 (m, 1H), 1.49 (q, J=5.8, 3.4 Hz, 2H), 1.45-1.32 (m, 2H), 1.31-1.09 (m, 8H), 1.05 (d, J=6.1 Hz, 3H), 0.99-0.73 (m, 12H), 0.69 (d, J=6.8 Hz, 3H), 0.58 (d, J=6.5 Hz, 3H), −0.67 (t, J=12.4 Hz, 1H).

(93) .sup.13C NMR (101 MHz, DMSO-d6): δ 173.33, 173.12, 171.96, 171.18, 170.49, 169.48, 166.25, 155.37, 138.91, 136.85, 129.92, 128.67, 128.05, 127.43, 127.10, 126.39, 79.77, 73.18, 65.35, 62.35, 58.35, 55.56, 53.60, 49.27, 47.66, 47.03, 46.94, 38.86, 37.05, 30.90, 29.58, 28.72, 23.95, 23.32, 23.25, 23.17, 21.16, 19.54, 19.45, 19.17, 16.70, 15.95, 15.27.

(94) LC-MS (ESI): t.sub.R=8.73 min; m/z=977.1 [M+H].sup.+, 959.1 [M+H—H.sub.2O].sup.+, 994.0 [M+Na].sup.+, calcd. for C.sub.50H.sub.72N.sub.8O.sub.12: 976.53.

(95) ##STR00022##

(96) Ahp10 (27) was synthesized via the ‘general synthesis procedure for Ahp-cyclodepsipeptides’.

(97) Yield: 12.5 mg (12.6 μmol, 6.3%) as a white solid.

(98) .sup.1H NMR (400 MHz, DMSO-d6): δ 8.33 (d, J=9.6 Hz, 1H), 7.99-7.96 (m, 2H), 7.45 (d, J=7.7 Hz, 1H), 7.42-7.09 (m, 12H), 5.93 (d, J=3.2 Hz, 1H), 5.15-5.06 (m, 2H), 5.02 (s, 2H), 4.93 (dd, J=9.7, 3.0 Hz, 1H), 4.87 (d, J=3.2 Hz, 1H), 4.81-4.74 (m, 1H), 4.54 (dd, J=11.1, 4.0 Hz, 1H), 4.50-4.43 (m, 1H), 4.43-4.35 (m, 1H), 4.30 (dd, J=9.6, 4.0 Hz, 1H), 4.07 (p, J=7.2 Hz, 1H), 3.22 (dd, J=14.3, 2.9 Hz, 1H), 2.82 (dd, J=14.1, 11.6 Hz, 1H), 2.75 (s, 3H), 2.69-2.55 (m, 1H), 2.45-2.31 (m, 1H), 2.30-2.16 (m, 1H), 2.01-1.91 (m, 1H), 1.84-1.64 (m, 3H), 1.58-1.51 (m, 1H), 1.20 (d, J=7.0 Hz, 6H), 0.91 (dd, J=6.9, 4.3 Hz, 6H), 0.86 (d, J=6.5 Hz, 3H), 0.81 (d, J=6.9 Hz, 3H), 0.77 (d, J=6.9 Hz, 3H), 0.68 (dd, J=10.2, 6.7 Hz, 7H), 0.43 (d, J=6.5 Hz, 3H), 0.27-0.21 (m, 1H).

(99) .sup.13C NMR (101 MHz, DMSO-d6): δ 172.62, 172.15, 171.64, 170.38, 169.91, 169.84, 169.42, 169.15, 158.75, 137.53, 137.02, 129.23, 128.57, 128.32, 127.73, 127.64, 126.42, 73.37, 67.26, 65.29, 60.51, 56.95, 55.61, 52.46, 49.82, 48.57, 47.65, 47.56, 33.88, 30.81, 30.62, 27.76, 23.79, 23.53, 22.24, 19.65, 19.21, 19.05, 18.44, 18.14, 18.04, 16.16.

(100) LC-MS (ESI): t.sub.R=8.67 min; m/z=991.0 [M+H].sup.+, 973.2 [M+H—H.sub.2O].sup.+, 1013.5 [M+Na].sup.+, calcd. for C.sub.51H.sub.74N.sub.8O.sub.12: 990.54.

(101) ##STR00023##

(102) Ahp11 was synthesized via the ‘general synthesis procedure for Ahp-cyclodepsipeptides’.

(103) Yield: 3.7 mg (4.2 μmol, 2.1%) as a white solid.

(104) .sup.1H NMR (400 MHz, DMSO-d6): δ 8.73 (d, J=9.6 Hz, 1H), 8.41 (d, J=3.9 Hz, 1H), 8.27 (d, J=7.6 Hz, 1H), 8.00 (d, J=9.6 Hz, 1H), 7.44 (d, J=9.4 Hz, 1H), 7.32-7.22 (m, 10H), 5.44 (d, J=4.6 Hz, 1H), 5.15 (dd, J=6.3, 2.4 Hz, 1H), 4.84 (dd, J=11.5, 3.1 Hz, 1H), 4.77-4.69 (m, 1H), 4.63 (dd, J=9.6, 3.5 Hz, 1H), 4.60-4.53 (m, 1H), 4.50 (dd, J=14.0, 6.7 Hz, 1H), 4.43 (d, J=9.0 Hz, 1H), 4.06 (dd, J=9.6, 7.8 Hz, 1H), 3.59-3.46 (m, 1H), 2.96 (dd, J=14.1, 11.5 Hz, 1H), 2.85 (m, 2H), 2.74 (s, 4H), 2.46-2.24 (m, 2H), 1.86-1.68 (m, 2H), 1.68-1.45 (m, 2H), 1.21 (dt, J=7.4, 3.7 Hz, 5H), 1.08 (d, J=6.2 Hz, 3H), 0.86 (d, J=6.9 Hz, 1H), 0.78 (m, 12H), 0.70 (d, J=6.8 Hz, 2H), 0.66 (d, J=6.6 Hz, 1H), 0.61 (d, J=6.6 Hz, 3H), 0.43 (d, J=6.5 Hz, 1H), −0.60 (t, J=12.3 Hz, 1H).

(105) LC-MS (ESI): t.sub.R=8.56 min; m/z=890.25 [M+H].sup.+, 872.23 [M+H—H.sub.2O].sup.+, 912.67 [M+Na].sup.+, calcd. for C.sub.51H.sub.74N.sub.8O.sub.12: 889.49.

(106) ##STR00024##

(107) Ahp12 was synthesized via the ‘general synthesis procedure for Ahp-cyclodepsipeptides’.

(108) Yield: 1.0 mg (0.9 μmol, 0.5%) as a white solid.

(109) .sup.1H NMR (700 MHz, DMSO-d6): δ 9.05 (d, J=9.6 Hz, 1H), 8.45-8.41 (m, 1H), 8.24 (t, J=8.5 Hz, 2H), 7.59 (d, J=10.0 Hz, 1H), 7.36 (t, J=6.3 Hz, 1H), 7.34-7.18 (m, 15H), 5.65-5.61 (m, 1H), 5.48 (t, J=5.3 Hz, 1H), 5.11 (d, J=10.1 Hz, 1H), 4.94 (d, J=9.5 Hz, 2H), 4.79 (m, 3H), 4.60 (m, 1H), 4.56-4.52 (m, 1H), 4.41 (d, J=9.1 Hz, 1H), 4.12 (q, J=7.8 Hz, 1H), 4.08-4.01 (m, 2H), 3.64-3.56 (m, 1H), 2.87 (m, 1H), 2.74 (s, 5H), 2.12 (m, 1H), 1.80-1.72 (m, 2H), 1.56 (m, 2H), 1.48 (dd, J=12.3, 6.8 Hz, 1H), 1.14 (d, J=7.2 Hz, 3H), 0.97 (d, J=6.9 Hz, 2H), 0.83 (t, J=7.1 Hz, 6H), 0.77 (d, J=6.6 Hz, 12H), 0.68 (t, J=6.6 Hz, 3H), 0.54 (d, J=6.5 Hz, 3H), −0.69 (t, J=12.4 Hz, 1H).

(110) LC-MS (ESI): t.sub.R=9.47 min; m/z=1067.30 [M+H].sup.+, 1049.19 [M+H—H.sub.2O].sup.+, 1089.67 [M+Na].sup.+, calcd. for C.sub.57H.sub.78N.sub.8O.sub.12: 1066.57.

(111) ##STR00025##

(112) Ahp13 was synthesized via the ‘general synthesis procedure for Ahp-cyclodepsipeptides’.

(113) Yield: 1.2 mg (1.3 μmol, 0.6%) as a white solid.

(114) .sup.1H NMR (400 MHz, DMSO-d6): δ 8.81 (d, J=9.6 Hz, 1H), 8.50 (d, J=7.6 Hz, 1H), 8.44 (d, J=4.1 Hz, 1H), 8.24 (d, J=9.4 Hz, 1H), 7.40-7.10 (m, 12H), 5.60 (d, J=5.4 Hz, 1H), 5.44-5.38 (m, 1H), 5.13 (dt, J=6.3, 3.6 Hz, 1H), 4.90 (d, J=2.2 Hz, 2H), 4.65 (dd, J=9.6, 3.4 Hz, 1H), 4.49 (dd, J=8.6, 6.0 Hz, 2H), 4.41 (dd, J=9.1, 5.9 Hz, 2H), 4.32-4.22 (m, 1H), 4.09 (q, J=5.4 Hz, 1H), 3.76 (d, J=13.4 Hz, 1H), 3.17 (d, J=4.8 Hz, 1H), 2.89 (dd, J=13.8, 11.2 Hz, 1H), 2.74 (s, 3H), 1.90-1.82 (m, 1H), 1.62 (s, 1H), 1.50 (dt, J=10.6, 4.8 Hz, 2H), 1.22 (dd, J=14.6, 7.0 Hz, 8H), 1.06 (dd, J=19.5, 6.5 Hz, 6H), 0.92 (t, J=12.9 Hz, 1H), 0.81 (dd, J=8.7, 6.7 Hz, 6H), 0.70 (d, J=6.8 Hz, 3H), 0.60 (d, J=6.6 Hz, 3H).

(115) LC-MS (ESI): t.sub.R=7.98 min; m/z=935.23 [M+H].sup.+, 917.28 [M+H—H.sub.2O].sup.+, 957.61 [M+Na].sup.+, calcd. for C.sub.47H.sub.66N.sub.8O.sub.12: 934.48.

(116) ##STR00026##

(117) Ahp14 was synthesized via the ‘general synthesis procedure for Ahp-cyclodepsipeptides’.

(118) Yield: 1.2 mg (1.3 μmol, 1.3%) as a white solid.

(119) .sup.1H NMR (400 MHz, DMSO-d6): δ 8.83 (d, J=9.6 Hz, 1H), 8.50 (d, J=7.5 Hz, 1H), 8.44 (d, J=4.0 Hz, 1H), 8.14 (d, J=9.6 Hz, 1H), 7.36-7.09 (m, 12H), 5.42 (d, J=4.5 Hz, 1H), 5.11 (m, 1H), 4.91 (d, J=6.1 Hz, 3H), 4.66 (dd, J=9.7, 3.3 Hz, 1H), 4.58-4.47 (m, 3H), 4.42 (d, J=9.0 Hz, 1H), 4.32-4.19 (m, 2H), 3.85-3.73 (m, 1H), 2.89 (dd, J=13.9, 11.4 Hz, 1H), 2.75 (s, 3H), 1.82 (dd, J=12.3, 6.2 Hz, 1H), 1.69-1.58 (m, 1H), 1.57-1.47 (m, 3H), 1.36 (m, 1H), 1.28-1.17 (m, 9H), 1.04 (d, J=6.2 Hz, 3H), 0.94 (m, 1H), 0.84-0.77 (m, 9H), 0.70 (d, J=6.8 Hz, 3H), 0.61 (d, J=6.5 Hz, 3H), −0.62 (t, J=12.4 Hz, 1H).

(120) LC-MS (ESI): t.sub.R=8.13 min; m/z=949.65 [M+H].sup.+, 931.18 [M+H—H.sub.2O].sup.+, 971.72 [M+Na].sup.+, calcd. for C.sub.48H.sub.68N.sub.8O.sub.12: 948.50.

(121) ##STR00027##

(122) Ahp15 was synthesized via the ‘general synthesis procedure for Ahp-cyclodepsipeptides’.

(123) Yield: 1.0 mg (1.0 μmol, 1.0%) as a white solid.

(124) .sup.1H NMR (400 MHz, DMSO-d6): δ 8.84 (d, J=9.7 Hz, 1H), 8.48 (t, J=5.5 Hz, 2H), 8.12 (d, J=9.6 Hz, 1H), 7.39-7.03 (m, 13H), 5.42 (d, J=4.3 Hz, 1H), 5.10 (m, 1H), 4.90 (s, 3H), 4.66 (dd, J=9.7, 3.3 Hz, 1H), 4.59-4.44 (m, 3H), 4.41-4.21 (m, 3H), 3.79 (dd, J=14.1, 2.6 Hz, 1H), 2.90 (dd, J=13.9, 11.5 Hz, 1H), 2.74 (s, 3H), 1.88-1.78 (m, 1H), 1.62 (m, 1H), 1.50 (dt, J=11.1, 4.8 Hz, 2H), 1.39 (m, 2H), 1.28-1.18 (m, 9H), 1.05 (d, J=6.2 Hz, 3H), 0.99-0.87 (m, 1H), 0.85-0.76 (m, 9H), 0.69 (d, J=6.8 Hz, 3H), 0.60 (d, J=6.6 Hz, 4H), −0.64 (t, J=12.4 Hz, 1H).

(125) LC-MS (ESI): t.sub.R=8.31 min; m/z=963.18 [M+H].sup.+, 945.36 [M+H—H.sub.2O].sup.+, 985.64 [M+Na].sup.+, calcd. for C.sub.49H.sub.70N.sub.8O.sub.12: 962.51.

(126) ##STR00028##

(127) Ahp16 was synthesized via the ‘general synthesis procedure for Ahp-cyclodepsipeptides’.

(128) Yield: 2.3 mg (2.4 μmol, 1.2%) as a white solid.

(129) .sup.1H NMR (400 MHz, DMSO-d6): δ 8.90 (d, J=9.6 Hz, 1H), 8.50 (d, J=7.4 Hz, 1H), 8.43 (d, J=4.2 Hz, 1H), 8.04 (dd, J=8.6, 2.5 Hz, 1H), 7.42-7.01 (m, 12H), 5.44 (d, J=5.0 Hz, 1H), 5.13-5.04 (m, 1H), 4.91 (d, J=5.4 Hz, 3H), 4.67 (dd, J=9.6, 3.2 Hz, 1H), 4.59-4.42 (m, 4H), 4.34-4.23 (m, 1H), 4.11 (t, J=9.4 Hz, 1H), 3.84-3.73 (m, 1H), 2.90 (dd, J=13.9, 11.4 Hz, 1H), 2.75 (s, 3H), 2.33 (m, 1H), 1.79 (dd, J=12.4, 6.8 Hz, 1H), 1.55 (m, 4H), 1.34 (dqd, J=14.7, 7.3, 3.0 Hz, 1H), 1.22 (dd, J=18.4, 7.1 Hz, 9H), 1.04 (d, J=6.1 Hz, 3H), 1.01-0.86 (m, 1H), 0.78 (dt, J=22.8, 6.8 Hz, 12H), 0.69 (d, J=6.8 Hz, 3H), 0.60 (d, J=6.6 Hz, 3H), −0.62 (t, J=12.4 Hz, 1H).

(130) LC-MS (ESI): t.sub.R=8.63 min; m/z=977.20 [M+H].sup.+, 959.25 [M+H—H.sub.2O].sup.+, 999.61 [M+Na].sup.+, calcd. for C.sub.50H.sub.72N.sub.8O.sub.12: 976.53.

(131) ##STR00029##

(132) Ahp17 was synthesized via the ‘general synthesis procedure for Ahp-cyclodepsipeptides’.

(133) Yield: 1.1 mg (1.1 μmol, 1.1%) as a white solid.

(134) .sup.1H NMR (400 MHz, DMSO-d6): δ 8.83 (d, J=9.6 Hz, 1H), 8.52 (d, J=7.3 Hz, 1H), 8.45 (d, J=4.2 Hz, 1H), 8.22 (d, J=9.5 Hz, 1H), 7.44-7.01 (m, 13H), 5.62 (d, J=5.5 Hz, 1H), 5.42 (d, J=5.2 Hz, 1H), 5.16-5.11 (m, 1H), 5.07 (d, J=1.9 Hz, 1H), 5.04-4.99 (m, 2H), 4.90 (d, J=6.0 Hz, 3H), 4.66 (dd, J=9.7, 3.3 Hz, 1H), 4.53-4.47 (m, 3H), 4.38 (dd, J=12.1, 7.9 Hz, 2H), 4.32-4.26 (m, 1H), 3.79 (d, J=13.1 Hz, 1H), 2.89 (dd, J=13.8, 11.3 Hz, 1H), 2.74 (s, 3H), 2.40-2.07 (m, 3H), 1.86-1.80 (m, 1H), 1.62 (s, 1H), 1.54-1.44 (m, 3H), 1.20 (d, J=7.3 Hz, 4H), 1.07-1.01 (m, 4H), 0.90-0.82 (m, 2H), 0.80 (t, J=5.9 Hz, 7H), 0.69 (d, J=6.8 Hz, 3H), 0.60 (d, J=6.5 Hz, 3H), −0.63 (t, J=12.5 Hz, 1H).

(135) LC-MS (ESI): t.sub.R=8.31 min; m/z=961.32 [M+H].sup.+, 943.30 [M+H—H.sub.2O].sup.+, 983.70 [M+Na].sup.+, calcd. for C.sub.49H.sub.68N.sub.8O.sub.12: 960.50.

(136) ##STR00030##

(137) Ahp18 was synthesized via the ‘general synthesis procedure for Ahp-cyclodepsipeptides’.

(138) Yield: 2.4 mg (2.5 μmol, 2.5%) as a white solid.

(139) LC-MS (ESI): t.sub.R=8.23 min; m/z=959.30 [M+H].sup.+, 941.21 [M+H—H.sub.2O].sup.+, 981.69 [M+Na].sup.+, calcd. for C.sub.49H.sub.66N.sub.8O.sub.12: 958.48.

(140) ##STR00031##

(141) Ahp19 was synthesized via the ‘general synthesis procedure for Ahp-cyclodepsipeptides’.

(142) Yield: 2.0 mg (2.1 μmol, 2.1%) as a white solid.

(143) .sup.1H NMR (400 MHz, DMSO-d6): δ 8.80 (d, J=9.6 Hz, 1H), 8.49 (d, J=7.6 Hz, 1H), 8.45 (d, J=4.0 Hz, 1H), 8.26 (d, J=9.6 Hz, 1H), 7.41-7.02 (m, 12H), 5.69 (d, J=5.6 Hz, 1H), 5.41 (t, J=5.3 Hz, 1H), 5.13-5.05 (m, 1H), 4.92-4.82 (m, 3H), 4.64 (dd, J=9.7, 3.3 Hz, 1H), 4.61-4.42 (m, 3H), 4.40 (d, J=9.1 Hz, 1H), 4.32-4.21 (m, 1H), 3.95 (m, 1H), 3.79 (d, J=13.9 Hz, 1H), 2.89 (dd, J=14.0, 11.4 Hz, 1H), 2.73 (s, 4H), 2.44-2.22 (m, 1H), 1.78 (dd, J=12.4, 6.4 Hz, 1H), 1.66-1.44 (m, 2H), 1.20 (d, J=7.2 Hz, 5H), 1.04 (d, J=6.1 Hz, 3H), 0.99-0.82 (m, 2H), 0.78 (dd, J=6.8, 3.9 Hz, 7H), 0.68 (d, J=6.8 Hz, 3H), 0.60 (d, J=6.6 Hz, 4H), 0.45-0.29 (m, 3H), 0.13 (m, 1H), −0.63 (t, J=12.4 Hz, 1H).

(144) LC-MS (ESI): t.sub.R=8.14 min; m/z=961.31 [M+H].sup.+, 943.27 [M+H—H.sub.2O].sup.+, 983.70 [M+Na].sup.+, calcd. for C.sub.49H.sub.66N.sub.8O.sub.12: 960.50.

(145) ##STR00032##

(146) Ahp20 was synthesized via the ‘general synthesis procedure for Ahp-cyclodepsipeptides’.

(147) Yield: 1.4 mg (1.4 μmol, 1.4%) as a white solid.

(148) .sup.1H NMR (400 MHz, DMSO-d6): δ 8.89 (d, J=9.6 Hz, 1H), 8.53-8.45 (m, 2H), 7.94 (d, J=9.9 Hz, 1H), 7.50-7.44 (m, 1H), 7.41-7.05 (m, 11H), 5.66 (s, 1H), 5.46 (s, 1H), 5.12 (d, J=6.6 Hz, 1H), 5.03 (s, 1H), 4.89 (d, J=14.1 Hz, 3H), 4.66 (dd, J=9.7, 3.2 Hz, 1H), 4.60 (d, J=9.9 Hz, 1H), 4.57-4.48 (m, 2H), 4.28 (q, J=8.4, 7.6 Hz, 1H), 4.19-4.14 (m, 1H), 3.78 (d, J=13.6 Hz, 1H), 2.96-2.84 (m, 1H), 2.75 (d, J=1.4 Hz, 3H), 2.36-2.24 (m, 1H), 1.76 (dd, J=12.1, 7.1 Hz, 1H), 1.68 (d, J=26.3 Hz, 2H), 1.51 (m, 3H), 1.21 (d, J=7.6 Hz, 4H), 1.06 (d, J=6.1 Hz, 3H), 0.85 (s, 11H), 0.80 (dd, J=6.8, 2.7 Hz, 6H), 0.69 (d, J=6.6 Hz, 3H), 0.62 (d, J=6.6 Hz, 3H), −0.60 (t, J=12.4 Hz, 1H).

(149) LC-MS (ESI): t.sub.R=8.55 min; m/z=977.43 [M+H].sup.+, 959.33 [M+H—H.sub.2O].sup.+, 999.78 [M+Na].sup.+, calcd. for C.sub.50H72N.sub.8O.sub.12: 976.53.

(150) ##STR00033##

(151) Ahp21 was synthesized via the ‘general synthesis procedure for Ahp-cyclodepsipeptides’.

(152) Yield: 2.9 mg (2.9 μmol, 2.9%) as a white solid.

(153) .sup.1H NMR (400 MHz, DMSO-d6): δ 8.86 (d, J=9.6 Hz, 1H), 8.51 (d, J=7.5 Hz, 1H), 8.40 (d, J=4.1 Hz, 1H), 7.99 (d, J=9.7 Hz, 1H), 7.38-7.02 (m, 12H), 5.65 (d, J=5.3 Hz, 1H), 5.42 (t, J=5.2 Hz, 1H), 5.10 (m, 1H), 4.90 (s, 3H), 4.66 (dd, J=9.7, 3.1 Hz, 1H), 4.60-4.42 (m, 5H), 4.34-4.21 (m, 1H), 4.09 (t, J=9.2 Hz, 1H), 3.86-3.74 (m, 1H), 2.95-2.83 (m, 1H), 2.74 (s, 3H), 2.41-2.26 (m, 1H), 1.80 (dd, J=12.4, 6.7 Hz, 2H), 1.56-1.38 (m, 2H), 1.25-1.17 (m, 13H), 1.05 (t, J=7.6 Hz, 5H), 0.97-0.85 (m, 2H), 0.80 (t, J=7.2 Hz, 6H), 0.69 (d, J=6.9 Hz, 3H), 0.62 (d, J=6.6 Hz, 4H), −0.61 (t, J=12.4 Hz, 1H).

(154) LC-MS (ESI): t.sub.R=8.93 min; m/z=1003.33 [M+H].sup.+, 985.51 [M+H—H.sub.2O].sup.+, 1025.81 [M+Na].sup.+, calcd. for C.sub.52H.sub.74N.sub.8O.sub.12: 1002.54.

(155) ##STR00034##

(156) Ahp22 was synthesized via the ‘general synthesis procedure for Ahp-cyclodepsipeptides’.

(157) Yield: 1.8 mg (1.8 μmol, 1.8%) as a white solid.

(158) .sup.1H NMR (400 MHz, DMSO-d6): δ 8.29 (d, J=8.9 Hz, 1H), 7.81 (d, J=7.4 Hz, 1H), 7.63 (d, J=9.2 Hz, 1H), 7.24 (t, J=9.2 Hz, 2H), 7.16-6.92 (m, 11H), 5.79 (d, J=3.2 Hz, 1H), 5.25 (dt, J=7.4, 6.0 Hz, 1H), 4.79 (s, 2H), 4.64 (dt, J=6.5, 3.0 Hz, 2H), 4.48 (dd, J=9.6, 4.5 Hz, 1H), 4.36 (dd, J=9.2, 1.3 Hz, 1H), 4.27-4.16 (m, 3H), 3.85 (m, 1H), 3.70 (t, J=8.3 Hz, 1H), 2.98 (dd, J=14.2, 2.9 Hz, 1H), 2.58 (dd, J=14.0, 11.6 Hz, 1H), 2.50 (s, 3H), 1.90-1.81 (m, 1H), 1.63-1.47 (m, 2H), 1.46-1.32 (m, 1H), 1.23 (dt, J=8.6, 6.1 Hz, 2H), 0.98 (dt, J=13.8, 7.5 Hz, 13H), 0.63 (d, J=6.9 Hz, 3H), 0.52-0.47 (m, 4H), 0.32 (m, 1H), 0.11 (m, 1H), 0.01 (m, 1H), −0.09 (m, 1H).

(159) LC-MS (ESI): t.sub.R=7.05 min; m/z=977.27 [M+H].sup.+, 959.28 [M+H—H.sub.2O].sup.+, 999.60 [M+Na].sup.+, calcd. for C.sub.48H.sub.64N.sub.8O.sub.14: 976.45.

(160) ##STR00035##

(161) Ahp23 was synthesized via the ‘general synthesis procedure for Ahp-cyclodepsipeptides’.

(162) Yield: 0.3 mg (0.3 μmol, 0.3%) as a white solid.

(163) LC-MS (ESI): t.sub.R=7.05 min; m/z=963.00 [M+H].sup.+, 945.31 [M+H—H.sub.2O].sup.+, 985.61 [M+Na].sup.+, calcd. for C.sub.47H.sub.62N.sub.8O.sub.14: 962.44.

(164) ##STR00036##

(165) Ahp24 was synthesized via the ‘general synthesis procedure for Ahp-cyclodepsipeptides’.

(166) Yield: 2.3 mg (2.4 μmol, 2.4%) as a white solid.

(167) .sup.1H NMR (400 MHz, DMSO-d6): δ 8.27 (d, J=8.9 Hz, 1H), 7.81 (d, J=7.3 Hz, 1H), 7.69 (d, J=9.2 Hz, 1H), 7.24 (d, J=7.7 Hz, 1H), 7.17-6.93 (m, 12H), 6.72 (d, J=2.5 Hz, 1H), 6.51 (d, J=2.5 Hz, 1H), 5.68 (d, J=3.2 Hz, 1H), 5.26 (dt, J=7.5, 5.9 Hz, 1H), 4.98 (m, 2H), 4.80 (s, 2H), 4.76 (t, J=3.1 Hz, 1H), 4.48 (dd, J=9.5, 4.3 Hz, 1H), 4.37 (dd, J=9.2, 1.4 Hz, 1H), 4.23 (p, J=7.1 Hz, 1H), 4.06 (ddd, J=12.3, 9.0, 6.6 Hz, 1H), 3.86 (p, J=7.2 Hz, 1H), 3.73 (t, J=8.3 Hz, 1H), 3.02 (dd, J=14.0, 5.1 Hz, 1H), 2.65 (dd, J=13.9, 9.3 Hz, 1H), 2.44 (s, 3H), 2.19 (dd, J=14.8, 9.6 Hz, 1H), 1.86 (s, 1H), 1.56 (dt, J=15.3, 11.1 Hz, 3H), 1.25 (dd, J=14.7, 5.4 Hz, 1H), 1.07-0.97 (m, 7H), 0.94 (d, J=6.5 Hz, 3H), 0.64 (d, J=6.8 Hz, 4H), 0.50 (d, J=6.9 Hz, 3H), 0.33 (m, 1H), 0.16-0.07 (m, 1H), 0.01 (m, 1H), −0.09 (m, 1H).

(168) LC-MS (ESI): t.sub.R=6.50 min; m/z=962.23 [M+H].sup.+, 944.21 [M+H—H.sub.2O].sup.+, 984.55 [M+Na].sup.+, calcd. for C.sub.47H.sub.63N.sub.9O.sub.13: 961.45.

(169) ##STR00037##

(170) Ahp25 was synthesized via the ‘general synthesis procedure for Ahp-cyclodepsipeptides’.

(171) Yield: 1.1 mg (1.1 μmol, 1.1%) as a white solid.

(172) .sup.1H NMR (400 MHz, DMSO-d6): δ 8.53 (d, J=9.0 Hz, 1H), 8.05 (t, J=7.6 Hz, 1H), 7.88 (d, J=9.3 Hz, 1H), 7.51-7.43 (m, 2H), 7.44-7.14 (m, 11H), 5.99 (d, J=3.2 Hz, 1H), 5.50 (m, 1H), 5.34 (d, J=10.1 Hz, 2H), 5.01 (d, J=4.0 Hz, 3H), 4.95-4.86 (m, 2H), 4.72 (dd, J=9.5, 4.4 Hz, 1H), 4.59 (d, J=9.3 Hz, 1H), 4.42 (m, 3H), 4.08 (m, 2H), 3.94 (t, J=8.3 Hz, 1H), 2.88-2.76 (m, 1H), 2.72 (s, 3H), 2.67 (m, 3H), 2.33 (m, J=1.9 Hz, 1H), 2.22-2.03 (m, 1H), 1.75 (dd, J=17.8, 11.0 Hz, 3H), 1.22 (dt, J=13.0, 7.4 Hz, 11H), 1.09 (t, J=7.0 Hz, 2H), 0.84 (dd, J=17.5, 6.8 Hz, 6H), 0.72 (d, J=6.9 Hz, 3H), 0.55 (td, J=8.6, 4.0 Hz, 2H), 0.35 (m, 2H), 0.23 (m, 1H), 0.14 (m, 1H).

(173) LC-MS (ESI): t.sub.R=6.38 min; m/z=1005.33 [M+H].sup.+, 987.42 [M+H—H.sub.2O].sup.+, 1027.64 [M+Na].sup.+, calcd. for C.sub.49H.sub.68N.sub.10O.sub.13: 1004.50.

(174) ##STR00038##

(175) Ahp26 was synthesized via the ‘general synthesis procedure for Ahp-cyclodepsipeptides’.

(176) Yield: 0.5 mg (0.5 μmol, 0.5%) as a white solid.

(177) .sup.1H NMR (400 MHz, DMSO-d6): δ 8.49 (d, J=8.8 Hz, 1H), 8.03 (d, J=7.4 Hz, 1H), 7.84 (d, J=9.3 Hz, 1H), 7.50-7.18 (m, 14H), 7.06 (d, J=8.8 Hz, 1H), 6.82-6.75 (m, 2H), 6.07 (d, J=3.1 Hz, 1H), 5.42 (q, J=6.6 Hz, 1H), 5.05 (s, 1H), 5.02 (s, 2H), 4.92 (dd, J=11.5, 2.9 Hz, 1H), 4.73-4.63 (m, 2H), 4.55 (d, J=9.4 Hz, 1H), 4.45 (p, J=7.0 Hz, 1H), 4.08 (m, 1H), 3.80 (t, J=8.4 Hz, 1H), 3.68 (dt, J=12.1, 8.4 Hz, 1H), 3.14 (d, J=5.5 Hz, 1H), 2.90-2.81 (m, 1H), 2.79 (s, 3H), 2.44-2.30 (m, 1H), 2.08 (h, J=6.9 Hz, 1H), 1.64 (dt, J=24.6, 16.9 Hz, 3H), 1.26-1.19 (m, 8H), 1.16 (d, J=6.6 Hz, 3H), 0.90-0.84 (m, 3H), 0.76-0.70 (m, 4H), 0.51 (m, 1H), 0.31 (m, 1H), 0.20 (dt, J=9.8, 4.8 Hz, 1H), 0.09 (dt, J=9.7, 4.9 Hz, 1H).

(178) LC-MS (ESI): t.sub.R=6.51 min; m/z=1029.02 [M+H].sup.+, 1011.39 [M+H—H.sub.2O].sup.+, 1051.63 [M+Na].sup.+, calcd. for C.sub.52H.sub.65ClN.sub.8O.sub.12: 1028.44.

(179) ##STR00039##

(180) Ahp27 was synthesized via the ‘general synthesis procedure for Ahp-cyclodepsipeptides’.

(181) Yield: 2.1 mg (2.1 μmol, 1.1%) as a white solid.

(182) .sup.1H NMR (400 MHz, DMSO-d.sub.6) δ=−0.17-−0.06 (m, 1H), −0.04-0.06 (m, 1H), 0.06-0.18 (m, 1H), 0.25-0.37 (m, 4.5, 1H), 0.50-0.56 (d, J=6.9, 3H), 0.64-0.71 (d, J=6.9, 3H), 0.83-1.07 (m, 11H), 1.26-1.38 (t, J=13.6, 1H), 1.42-1.53 (m, 3H), 1.83-1.96 (m, 1H), 2.11-2.25 (m, 1H), 2.62-2.72 (m, 2H), 3.00-3.08 (d, J=12.6, 1H), 3.32-3.43 (m, 1H), 3.54-3.64 (t, J=8.5, 1H), 3.83-3.95 (p, J=7.1, 1H), 4.20-4.40 (m, 2H), 4.47-4.58 (m, 2H), 4.76-4.87 (m, 4H), 5.16-5.26 (q, J=6.5, 1H), 5.81-5.86 (d, J=3.2, 1H), 6.54-6.62 (m, 2H), 6.78-6.86 (d, J=8.8, 1H), 6.86-7.09 (m, 6H), 7.09-7.32 (m, 10H), 7.61-7.68 (d, J=9.3, 1H), 7.78-7.87 (d, J=7.4, 1H), 8.27-8.34 (d, J=8.9, 1H).

(183) ##STR00040##

(184) Ahp28 was synthesized via the ‘general synthesis procedure for Ahp-cyclodepsipeptides’.

(185) Yield: 1.88 mg (1.6 μmol, 0.88%) as a white solid.

(186) LC-MS (ESI): t.sub.R=8.94 min; m/z=1072.83 [M+H].sup.+, 1074.80 [M+H].sup.+ calcd. for C.sub.52H.sub.65BrN.sub.8O.sub.12: 1072.39, 1074.39.

(187) ##STR00041##

(188) Ahp29 was synthesized via the ‘general synthesis procedure for Ahp-cyclodepsipeptides’.

(189) Yield: 14.2 mg (13.9 μmol, 7.0%) as a white solid.

(190) .sup.1H NMR (400 MHz, DMSO-d.sub.6) δ=−0.07-0.03 (m, 1H), 0.09-0.26 (m, 2H), 0.28-0.40 (m, 1H), 0.60-0.74 (m, 6H), 0.82-1.17 (m, 11H), 1.18-1.36 (m, 4H), 1.44-1.61 (s, 2H), 1.97-2.10 (m, 1H), 2.36-2.51 (m, 2H), 2.82-2.97 (m, 1H), 3.18-3.25 (m, 2H), 3.42-3.53 (t, J=7.9, 1H), 3.87-3.97 (m, 1H), 3.96-4.01 (m, 1H), 4.04-4.11 (t, J=6.9, 1H), 4.18-4.24 (q, J=7.1, 1H), 4.29-4.33 (t, J=4.9, 1H), 4.37-4.51 (m, 2H), 4.79-4.90 (d, J=2.5, 2H), 4.99-5.21 (m, 2H), 6.75-6.83 (d, J=8.5, 1H), 6.86-6.95 (m, 1H), 6.95-7.02 (m, 2H), 7.10-7.34 (m, 10H), 7.36-7.40 (s, 1H), 7.47-7.51 (m, 1H), 7.71-7.78 (t, J=7.8, 1H), 7.84-7.91 (d, J=7.3, 1H), 8.37-8.43 (d, J=7.7, 1H), 8.51-8.58 (d, J=6.2, 1H).

(191) ##STR00042##

(192) Ahp30 was synthesized via the ‘general synthesis procedure for Ahp-cyclodepsipeptides’.

(193) Yield: 6.3 mg (6.2 μmol, 3.1%) as a white solid.

(194) .sup.1H NMR (400 MHz, DMSO-d.sub.6) δ=−0.07-0.04 (m, 1H), 0.09-0.26 (m, 2H), 0.29-0.40 (m, 1H), 0.62-0.72 (t, J=6.7, 6H), 0.78-0.85 (q, J=7.5, 1H), 0.85-0.94 (m, 2H), 0.94-0.99 (d, J=6.5, 3H), 1.00-1.06 (d, J=7.2, 5H), 1.06-1.09 (d, J=4.6, 1H), 1.19-1.37 (m, 3H), 1.41-1.58 (m, 2H), 1.95-2.08 (h, J=6.8, 1H), 2.25-2.32 (m, 0H), 2.44-2.51 (m, 1H), 2.79-2.95 (m, 2H), 3.41-3.50 (t, J=7.9, 1H), 3.84-3.96 (p, J=7.2, 1H), 3.96-4.15 (m, 3H), 4.16-4.28 (m, 1H), 4.28-4.35 (t, J=4.9, 1H), 4.37-4.56 (m, 2H), 4.79-4.91 (d, J=2.9, 2H), 4.99-5.15 (m, 2H), 6.72-6.87 (m, 4H), 6.87-6.96 (m, 1H), 6.96-7.02 (m, 2H), 7.05-7.23 (m, 8H), 7.24-7.34 (m, 1H), 7.66-7.78 (d, J=8.7, 1H), 7.84-7.91 (d, J=7.4, 1H), 8.37-8.44 (d, J=7.7, 1H), 8.50-8.63 (m, 1H).

(195) ##STR00043##

(196) Ahp31 was synthesized via the ‘general synthesis procedure for Ahp-cyclodepsipeptides’.

(197) Yield: 6.7 mg (6.7 μmol, 3.4%) as a white solid.

(198) .sup.1H NMR (400 MHz, DMSO-d.sub.6) δ=−0.02-0.13 (d, J=14.2, 1H), 0.15-0.26 (m, 1H), 0.35-0.54 (m, 3H), 0.69-0.78 (m, 3H), 0.79-0.85 (d, J=6.9, 3H), 0.86-0.93 (m, 1H), 1.07-1.13 (d, J=6.2, 3H), 1.21-1.26 (d, J=7.2, 3H), 1.26-1.30 (s, 8H), 1.30-1.35 (d, J=7.0, 2H), 1.53-1.64 (m, 1H), 1.75-1.87 (m, 1H), 2.01-2.08 (m, 1H), 2.28-2.35 (m, 1H), 2.74-2.81 (d, J=4.8, 3H), 2.87-2.96 (m, 1H), 3.80-3.91 (d, J=13.5, 1H), 3.98-4.05 (d, J=8.8, 1H), 4.25-4.37 (m, 1H), 4.45-4.58 (m, 10.4, 2H), 4.59-4.74 (m, 3H), 4.92-4.94 (s, 2H), 5.10-5.17 (d, J=5.2, 1H), 5.43-5.53 (t, J=5.2, 1H), 5.73-5.81 (d, J=5.6, 1H), 6.83-6.94 (t, J=7.4, 1H), 7.02-7.42 (m, 15H), 7.52-7.61 (d, J=9.9, 1H), 8.30-8.37 (d, J=9.5, 1H), 8.49-8.57 (d, J=7.5, 1H), 8.78-8.80 (s, 1H).

(199) LC-MS (ESI): t.sub.R=8.30 min; m/z=1009.43 [M+H].sup.+, 1031.45 [M+Na].sup.+; calcd. for C.sub.53H.sub.68N.sub.8O.sub.12: 1008.50.

(200) ##STR00044##

(201) Ahp32 was synthesized via the ‘general synthesis procedure for Ahp-cyclodepsipeptides’.

(202) Yield: 0.4 mg (0.35 μmol, 0.18%) as a white solid.

(203) .sup.1H NMR (400 MHz, DMSO-d.sub.6) δ=0.07-0.17 (d, J=5.0, 1H), 0.21-0.35 (m, 2H), 0.47-0.59 (m, 1H), 0.71-0.76 (d, J=6.9, 2H), 0.81-0.90 (m, 7H), 1.13-1.16 (d, J=7.1, 3H), 1.36-1.52 (d, J=6.9, 2H), 1.60-1.76 (s, 2H), 1.96-2.02 (m, 1H), 2.05-2.12 (s, 2H), 2.77-2.88 (d, J=20.0, 5H), 3.00-3.11 (d, J=13.1, 1H), 3.64-3.74 (m, 1H), 3.80-3.89 (t, J=8.4, 1H), 3.98-4.05 (t, J=7.4, 1H), 4.56-4.61 (d, J=9.2, 1H), 4.63-4.70 (s, 1H), 4.71-4.77 (m, 1H), 4.77-4.84 (s, 1H), 4.93-5.09 (m, 4H), 5.29-5.37 (t, J=4.7, 1H), 5.41-5.50 (d, J=6.8, 1H), 6.05-6.12 (d, J=3.0, 1H), 6.60-6.68 (s, 1H), 6.73-6.85 (d, J=8.3, 2H), 7.05-7.11 (d, J=8.9, 1H), 7.13-7.45 (m, 16H), 7.46-7.52 (d, J=9.6, 1H), 7.81-7.89 (d, J=8.2, 1H), 8.17-8.25 (d, J=9.1, 1H), 8.49-8.56 (d, J=9.0, 1H).

(204) LC-MS (ESI): t.sub.R=9.71 min; m/z=1139.53 [M+H].sup.+, 1162.27 [M+Na].sup.+; calcd. for C.sub.58H.sub.68Cl.sub.2N.sub.8O.sub.12: 1138.43.

(205) ##STR00045##

(206) Ahp33 was synthesized via the ‘general synthesis procedure for Ahp-cyclodepsipeptides’.

(207) Yield: 0.3 mg (0.27 μmol, 0.13%) as a white solid.

(208) .sup.1H NMR (400 MHz, DMSO-d.sub.6) δ=0.08-0.15 (d, J=6.5, 1H), 0.19-0.27 (m, 1H), 0.28-0.37 (m, 1H), 0.50-0.58 (d, J=6.0, 1H), 0.65-0.76 (d, J=6.8, 2H), 0.82-0.91 (q, J=7.0, 7H), 1.14-1.18 (d, J=7.4, 3H), 1.52-1.71 (s, 4H), 1.95-2.01 (s, 1H), 2.05-2.12 (s, 1H), 2.14-2.21 (t, J=7.3, 1H), 2.74-2.83 (d, J=15.7, 3H), 2.83-2.93 (m, 2H), 3.04-3.13 (d, J=12.3, 1H), 3.63-3.76 (m, 1H), 3.78-3.89 (t, J=8.5, 1H), 3.98-4.08 (t, J=7.3, 1H), 4.55-4.62 (d, J=9.1, 1H), 4.63-4.71 (d, J=10.1, 1H), 4.73-4.78 (dd, J=9.6, 4.4, 1H), 4.78-4.85 (s, 1H), 4.89-4.96 (d, J=11.3, 1H), 5.01-5.08 (d, J=24.1, 2H), 5.25-5.50 (m, 2H), 6.04-6.11 (d, J=3.1, 1H), 6.75-6.83 (d, J=8.2, 2H), 6.93-7.53 (m, 17H), 7.79-7.88 (d, J=7.9, 1H), 8.15-8.22 (d, J=9.3, 1H), 8.49-8.58 (d, J=8.9, 1H).

(209) LC-MS (ESI): t.sub.R=9.44 min; m/z=1122.61 [M+H].sup.+, 1145.30 [M+Na].sup.+; calcd. for C.sub.58H.sub.68ClFN.sub.8O.sub.12: 1122.46.

(210) ##STR00046##

(211) Ahp34 was synthesized via the ‘general synthesis procedure for Ahp-cyclodepsipeptides’.

(212) Yield: 0.96 mg (0.86 μmol, 0.42%) as a white solid.

(213) .sup.1H NMR (400 MHz, DMSO-d.sub.6) δ=−0.10-−0.01 (m, 1H), 0.07-0.15 (m, 1H), 0.29-0.35 (d, J=7.9, 2H), 0.64-0.72 (d, J=6.8, 3H), 0.76-0.81 (d, J=6.9, 3H), 0.81-0.89 (t, J=6.6, 3H), 0.92-1.00 (m, 1H), 1.03-1.08 (d, J=6.1, 2H), 1.08-1.17 (s, 2H), 1.19-1.23 (s, 4H), 1.39-1.55 (d, J=8.2, 2H), 1.78-2.01 (s, 2H), 2.03-2.14 (m, 2H), 2.22-2.30 (m, 1H), 2.73-2.81 (d, J=9.6, 3H), 2.85-2.94 (d, J=12.9, 1H), 3.65-3.71 (d, J=8.9, 1H), 3.84-3.94 (d, J=13.4, 1H), 4.19-4.25 (d, J=9.1, 1H), 4.25-4.42 (dt, J=31.6, 7.8, 2H), 4.59-4.71 (m, 2H), 4.80-4.89 (d, J=12.2, 1H), 4.90-4.94 (s, 1H), 4.99-5.06 (s, 3H), 5.35-5.42 (d, J=5.1, 1H), 5.66-5.70 (d, J=5.6, 1H), 6.95-7.03 (q, J=8.0, 7.0, 2H), 7.08-7.31 (m, 20H), 7.42-7.48 (d, J=9.9, 1H), 8.28-8.35 (d, J=9.5, 1H), 8.48-8.53 (d, J=3.8, 1H), 8.56-8.63 (d, J=7.5, 1H), 8.64-8.73 (d, J=9.8, 1H).

(214) LC-MS (ESI): t.sub.R=9.94 min; m/z=1118.79 [M+H].sup.+, 1141.37 [M+Na].sup.+; calcd. for C.sub.59H.sub.71ClN.sub.8O.sub.12: 1118.49.

(215) ##STR00047##

(216) Ahp35 was synthesized via the ‘general synthesis procedure for Ahp-cyclodepsipeptides’.

(217) Yield: 0.81 mg (0.73 μmol, 0.37%) as a white solid.

(218) .sup.1H NMR (400 MHz, DMSO-d.sub.6) δ=−0.16-−0.08 (s, 1H), −0.05-0.04 (d, J=5.4, 1H), 0.12-0.21 (d, J=7.9, 2H), 0.51-0.58 (d, J=6.8, 2H), 0.62-0.76 (m, 8H), 0.84-1.05 (m, 10H), 1.26-1.43 (s, 3H), 1.49-1.61 (m, 2H), 1.79-1.89 (s, 3H), 1.91-1.92 (s, 1H), 2.56-2.63 (s, 3H), 2.63-2.74 (d, J=30.4, 3H), 3.47-3.56 (d, J=12.9, 1H), 3.62-3.69 (m, 1H), 3.83-3.91 (q, J=7.1, 2H), 3.91-4.02 (t, J=7.7, 1H), 4.07-4.15 (d, J=9.2, 1H), 4.40-4.46 (d, J=8.9, 1H), 4.50-4.55 (m, 2H), 4.78-4.80 (s, 1H), 4.81-4.92 (d, J=14.5, 3H), 4.94-5.02 (d, J=6.7, 1H), 5.15-5.20 (t, J=4.8, 1H), 5.22-5.29 (t, J=5.0, 1H), 5.50-5.54 (d, J=5.5, 1H), 5.58-5.61 (s, 2H), 6.60-6.64 (d, J=7.4, 1H), 6.70-6.78 (d, J=7.4, 1H), 6.90-7.00 (d, J=6.7, 5H), 7.02-7.11 (m, 8H), 7.14-7.22 (s, 5H), 7.52-7.66 (d, J=9.6, 1H), 8.09-8.20 (t, J=9.8, 2H), 8.31-8.35 (d, J=3.7, 1H), 8.50-8.63 (d, J=9.8, 1H).

(219) LC-MS (ESI): t.sub.R=9.52 min; m/z=1104.93 [M+H].sup.+, 1128.39 [M+Na].sup.+; calcd. for C.sub.58H.sub.69ClN.sub.8O.sub.12: 1104.47.

(220) ##STR00048##

(221) Ahp36 was synthesized via the ‘general synthesis procedure for Ahp-cyclodepsipeptides’.

(222) Yield: 0.50 mg (0.46 μmol, 0.23%) as a white solid.

(223) .sup.1H NMR (400 MHz, DMSO-d.sub.6) δ=−0.02-0.07 (s, 1H), 0.07-0.18 (m, 1H), 0.20-0.41 (d, J=8.1, 4H), 0.44-0.55 (d, J=8.7, 1H), 0.65-0.76 (m, 4H), 0.76-0.91 (m, 7H), 0.99-1.18 (m, 9H), 1.21-1.34 (s, 5H), 1.37-1.58 (m, 3H), 1.58-1.72 (d, J=18.0, 2H), 1.89-2.22 (m, 3H), 2.22-2.35 (m, 2H), 2.69-2.81 (m, 4H), 2.81-2.93 (d, J=18.7, 3H), 2.93-3.09 (m, 2H), 3.12-3.21 (d, J=4.4, 4H), 3.52-3.70 (m, 2H), 3.73-3.86 (m, 2H), 3.94-4.16 (m, 4H), 4.16-4.31 (m, 2H), 4.53-4.63 (d, J=9.5, 1H), 4.64-4.76 (m, 3H), 4.86-5.08 (m, 6H), 5.36-5.46 (m, 2H), 5.65-5.70 (d, J=5.5, 1H), 5.99-6.08 (s, 1H), 6.72-6.82 (t, J=6.8, 2H), 6.83-7.48 (m, 21H), 7.68-7.74 (d, J=9.6, 1H), 7.79-7.86 (d, J=8.0, 1H), 7.86-7.94 (d, J=8.0, 1H), 8.13-8.23 (d, J=9.2, 1H), 8.23-8.37 (t, J=8.4, 2H), 8.52-8.64 (m, 1H), 8.66-8.74 (d, J=9.8, 1H).

(224) LC-MS (ESI): t.sub.R=9.20 min; m/z=1088.84 [M+H].sup.+, 1111.41 [M+Na].sup.+; calcd. for C.sub.58H.sub.69FN.sub.8O.sub.12: 1088.50.

(225) ##STR00049##

(226) Ahp37 was synthesized via the ‘general synthesis procedure for Ahp-cyclodepsipeptides’.

(227) Yield: 0.87 mg (0.79 μmol, 0.40%) as a white solid.

(228) .sup.1H NMR (400 MHz, DMSO-d.sub.6) δ=0.04-0.13 (s, 1H), 0.18-0.27 (d, J=4.9, 1H), 0.28-0.36 (d, J=8.1, 1H), 0.45-0.57 (s, 1H), 0.63-0.75 (m, 2H), 0.77-0.90 (m, 3H), 1.07-1.19 (m, 3H), 1.20-1.31 (s, 4H), 1.42-1.56 (s, 2H), 1.59-1.75 (d, J=12.9, 2H), 1.93-2.03 (m, 2H), 2.04-2.12 (s, 4H), 2.76-2.81 (s, 1H), 2.82-2.99 (d, J=13.7, 3H), 3.78-3.86 (s, 1H), 3.97-4.09 (t, J=7.4, 2H), 4.55-4.60 (d, J=8.9, 1H), 4.64-4.77 (m, 2H), 4.79-4.86 (s, 1H), 4.92-4.95 (s, 1H), 4.95-5.05 (m, 2H), 5.30-5.36 (s, 1H), 5.37-5.48 (d, J=7.0, 1H), 5.65-5.71 (d, J=5.0, 1H), 5.72-5.79 (s, 1H), 6.00-6.08 (s, 1H), 6.59-6.74 (s, 2H), 6.75-6.80 (d, J=7.3, 1H), 6.99-7.74 (m, 11H), 7.76-7.93 (d, J=7.6, 2H), 8.19-8.32 (dd, J=17.5, 8.8, 1H), 8.49-8.56 (s, 1H), 8.66-8.72 (s, 1H).

(229) LC-MS (ESI): t.sub.R=8.84 min; m/z=1095.83 [M+H].sup.+, 1118.44 [M+Na].sup.+; calcd. for C.sub.59H.sub.69N.sub.9O.sub.12: 1095.51.

Example 3: Biochemical Determination of the Protease Activity

(230) Enzymes

(231) The following enzymes were purchased from commercial distributors: humane neutrophil elastase (Enzo Life Sciences; BML-SE284), human pancreas chymotrypsin (Sigma-Aldrich; SRP6509-100, Lot #2D207538) and bovine pancreas trypsin (Sigma-Aldrich; T1426).

(232) Alternatively, the enzymes HTRA1 (aa 158-480, n-terminal StrepII-tag, from pET21d backbone), HTRA2 (aa 134-458, n-terminal His-tag, form pET28 backbone), and HTRA3 (aa 111-436, c-terminal His-tag, from pET21d backbone) were expressed and purified as described in the art.

(233) Chromogenic Enzyme Activity Assays

(234) In general, proteolytic activity was tested by monitoring the cleavage of the specific chromogenic substrate at 405 nm wavelength for 60 or 120 minutes in a Tecan Spark M10 or Tecan Genios Pro plate reader at 37° C. After optimization of assay conditions, every enzyme was tested in 100 μL final volume with 500 μM chromogenic substrate. Where applicable, inhibitor and enzyme were pre-incubated for 10 minutes in the buffer at 37° C. before substrate addition. Compounds were pre-solved in DMSO and used in the assays with a final DMSO concentration of 3% (v/v).

(235) TABLE-US-00001 TABLE 1 Overview on biochemical assay conditions. enzyme final conc. buffer substrate K.sub.M human 50 nM 100 mM HEPES, AAPV-pNA 256.8 μM neutrophil 500 mM, NaCl, (Sigma- elastase 0.05% (v/v) Aldrich; Tween-20, M4765) pH 7.25 human 100 nM 100 mM HEPES, AAF-pNA 1389 μM pancreas 500 mM NaCl, (Sigma- chymo- 0.05% (v/v) Aldrich; trypsin Tween-20, A9148 pH 7.25 bovine 100 nM 150 mM Nα-Benzoyl- n.d. pancreas NaH2PO4, DL- Arg- trypsin 380 mM NaCl, pNA × pH 8.3 HCl (Sigma- Aldrich; #B4875) HTRA1 1 μM 150 mM VFNTLPMMG 269 μM NaH2PO4, KASPV-pNA 380 mM NaCl, pH 8.3 HTRA2 1 μM 150 mM VFNTLPMMG 1347 μM NaH2PO4, KASPV-pNA 380 mM NaCl, pH 8.3 HTRA3 1 μM 500 mM VFNTLPMMG 388.2 μM NaH2PO4, KASPV-pNA pH 8.0

(236) The determined specific activities (sa) were derived from duplicate measurements and calculated as
sa=ΔOD405×V/(m×ε×t)

(237) (ΔOD405: change of absorption at λ=405 nm over specific time; V: final volume of reaction, m: amount of protease (mg), ε: molar extinction coefficient of para-nitroaniline, t: time interval for measurement).

(238) In order to determine K.sub.M values, the assays were performed as described but with differing substrate concentrations (10 μM to 4 mM). Specific activity was calculated and plotted against substrate concentrations in GraphPad Prism 5 software. Michaelis-Menten (software built-in) analysis was used to calculate the KM values. In order to determine IC.sub.50 and K.sub.i values, enzyme assays were performed with differing inhibitor concentrations (2.5 nM to 20/200 μM), specific activities were calculated, and plotted against log inhibitor concentrations in GraphPad Prism 5 software. One site—Fit K.sub.i and One site—Fit log IC.sub.50 (software built-in) analysis were used to calculate IC.sub.50 and K.sub.i values.

(239) Results

(240) 1. Amino Acid Variations at Different Positions

(241) After chemical synthesis of Ahp1-Ahp8, these compounds were analyzed in biochemical assays (Table 2).

(242) TABLE-US-00002 TABLE 2 Biochemical inhibition data for synthesized Ahp-cyclodepsipeptides. Ki [μM] Chymotrypsin Elastase Trypsin HTRA1 HTRA2 HTRA3 Cpd [a] [b] [c] [d] [d] [d] Ahp1 >50 0.019 ± 0.003 >50 8.2 ± 2.7 4.1 ± 0.4 3.0 ± 0.5 Ahp2 0.37 ± 0.08 >50 >50 >50 >50 >50 Ahp3 >50 0.21 ± 0.06 >50 >50 0.27 ± 0.07 3.1 ± 0.6 Ahp4 >50 0.33 ± 0.06 >50 >50 0.49 ± 0.11 >50 Ahp5 >50 6.4 ± 1.2 >50 >50 >50 >50 Ahp6 >50 8.0 ± 1.8 >50 10.3 ± 3.0  2.1 ± 0.3 >50 Ahp7 >50 0.11 ± 0.02 >50 >50 6.9 ± 1.5 >50 Ahp8 >50 0.32 ± 0.05 >50 >50 2.3 ± 0.2 9.5 ± 0.9 Ahp9 2.1 ± 0.2 3.4 ± 1.1 >50 >50 2.8 ± 0.7 >50 Ahp10 >50 0.018 ± 0.004 >50 2.4 ± 0.6 0.26 ± 0.03 0.48 ± 0.07 Ahp11 0.007 >50 4.0 9.5 [a] Human pancreas chymotrypsin, [b] human neutrophil elastase, [c] bovine trypsin, [d] human HTRA proteases.

(243) As expected, the change of the P1 position from Val to Phe in Ahp2 significantly reduced elastase and HTRA1-HTRA3 inhibition but enhanced chymotrypsin inhibition. The inhibition profile for elastase furthermore revealed that despite the preference for Val in P1, many other structural changes were well tolerated. Besides Ahp2, all generated compounds were low μM or even sub-μM elastase inhibitors, including Ahp7 with its N-MeAla residue at P3′, thereby demonstrating that the structurally conserved N-Me aromatic amino acids are not required to maintain high inhibitory potency. For the HTRA proteases, the inhibitory profile was much more sensitive. Besides Ahp1, HTRA1 and HTRA3 were inhibited only by Ahp6 and Ahp3/Ahp8, respectively, while other substitutions led to inactive compounds. HTRA2 was inhibited by all Ahp-cyclodepsipeptides except Ahp2, and the derivative Ahp4 was more than ten-fold more potent than Ahp1, thus displaying sub-μM inhibition potencies. Encouraged by these results, we performed another round of single substitutions at selected positions of Ahp1, using findings from a proteome-wide substrate screen that revealed a distinct selectivity for Leu at P2 and the finding that the P1 selectivity is not restricted to Val but may also accommodate Leu. We therefore synthesized three further derivatives Ahp9 with Leu at P1, Ahp10 with the non-proteinogenic amino acid (3-OH)Leu at P2, and Ahp11 lacking P4. Biochemical evaluation of these compounds revealed that Ahp9 displayed slightly better HTRA2 inhibitory properties than Ahp1. More intriguingly however, incorporation of (3-OH)Leu at P2 in Ahp10 led to a 15-fold more active compound with a sub-μM K.sub.i (Table 2). Of note, this structural change also lowered the K.sub.i for HTRA1 and elastase, thereby further demonstrating the potential of the Ahp-cyclodepsipeptide scaffold for generating tailored serine protease inhibitors. Ahp11 showed moderate inhibition of HTRA2 and HTRA3, but no inhibition of HTRA1.

(244) 2. Amino Acid Variations at Position P1

(245) In a further series, Ahp-cyclodepsipeptides with various different amino acids at the P1 position were synthesized. After chemical synthesis of Ahp13-Ahp21, these compounds were analyzed in biochemical assays (Table 3).

(246) TABLE-US-00003 TABLE 3 Biochemical inhibition data for synthesized Ahp-cyclodepsipeptides. Ki [μM] Compound HTRA1 [a] HTRA2 [a] HTRA3 [a] Elastase [b] Ahp13 4.26 0.26 0.98 0.026 Ahp14 2.97 0.70 1.46 0.47 Ahp15 7.0 0.69 >50 0.13 Ahp16 >50 >50 >50 0.50 Ahp17 >50 1.38 0.84 0.16 Ahp18 >50 17.9 0.20 Ahp19 1.24 1.11 0.74 1.93 Ahp20 >50 >50 8.3 4.32 Ahp21 >50 >50 >50 >50 [a] human HTRA proteases, [b] human neutrophil elastase

(247) Most of the variants, except for Ahp21, showed protease inhibition against at least one of HTRA1-3. Peptides Ahp13, Ahp14 and Ahp19 even had enhanced inhibitory activity for all HTRA proteases. An especially strong inhibitory effect was demonstrated for Ahp19, which has a cyclopropyl group as side chain at position P1.

(248) 3. Ahp-Cyclodepsipeptides with a Cyclopropyl Amino Acid at Position P1

(249) Different Ahp-cyclodepsipeptides with an amino acid having a cyclopropyl side chain at position P1 were synthesized. After chemical synthesis of Ahp22-Ahp37, these compounds were analyzed in biochemical assays (Table 4).

(250) TABLE-US-00004 TABLE 4 Biochemical inhibition data for synthesized Ahp-cyclodepsipeptides. Ki [μM] Compound HTRA1 [a] Ahp22 5.2 Ahp24 1.66 Ahp25 0.70 Ahp26 0.065 Ahp27 0.95 Ahp28 2.8 Ahp29 1.8 Ahp30 3.0 Ahp33 0.61 Ahp34 43.4 Ahp35 6.3 Ahp36 1.4 Ahp37 1.4 [a] human HTRA proteases

(251) In view of the strong inhibitory effect of Ahp19, variants of this peptide with different amino acids at position P2′ and P3 were generated and tested for their activity against HTRA1. Most of the peptides showed good inhibition, with Ahp25, Ahp26, Ahp27 and Ahp33 even having sub-μM Ki values. This demonstrates that polar or nonpolar large side chains, especially with aromatic rings, can be present at position P2′. Likewise, also position P3 tolerates large amino acids such as halogen-substituted phenylalanine.

Example 4: Biological Determination of the Protease Activity

(252) hBMSC Culture and Osteogenic Differentiation

(253) Human BMSCs (hBMSCs) (Lonza Verviers, Belgium) were maintained in normal growth medium consisting of Dulbecco's modified eagle medium (DMEM-low glucose, with Glutamax) (Thermo Fisher Scientific, Reinach, Switzerland), supplemented with 10% fetal bovine serum (FBS) (Bioswisstec, Schaffhausen, Switzerland) and penicillin (50 units mL.sup.−1) and streptomycin (50 μg mL.sup.−1), and used between passage 2 and 6. The osteogenic differentiation of hBMSCs was performed as previously described in the art. Briefly, hBMSCs were seeded at 10′000 cells cm-2 in 24-well cell culture plates, and incubated for up to 14 days in osteogenic medium consisting of normal growth medium supplemented with ascorbic acid (50 μM), β-glycerophosphate (10 mM) and dexamethasone (100 nM) (all from Sigma-Aldrich, Buchs, Switzerland). Cells were replenished with fresh medium every 3-4 days. At 7 days post-osteogenic induction, cells were treated with 5 μg mL.sup.−1 of catalytically active (HTRA1) or inactive (HTRA1SA) HTRA1 in the presence or absence of Ahp10 (27, 10 μM), and allowed to differentiate for a further 7 days. Mineralized matrix deposition by hBMSC-derived bone forming cells was visualized using Alizarin Red S, and the amount of staining quantified by determining the absorption at 570 nm using a multiplate reader (Infinite M200, Tecan) following extraction with 10% cetylpyridinium chloride (Sigma-Aldrich).

(254) Results

(255) As no defined cell culture-based assay for monitoring HTRA2 activity is yet available, we tested the bioactivity of Ahp-cyclodepsipeptides by monitoring osteogenesis of human bone marrow-derived stromal cells (hBMSCs), a process strictly dependent on HTRA1-mediated proteolysis. hBMSC-mediated matrix mineralization was visualized via Alizarin Red S staining after treatment with either 10 μM Ahp10 in the presence or absence of HTRA1 or the catalytically inactive mutant HTRA1 S328A (FIG. 2). These data demonstrated that Ahp10 significantly inhibited HTRA1-mediated hBMSC osteogenesis and thus the inhibition of HTRA1 by Ahp-cyclodepsipeptides in cell culture.