Synthesis process of precursors of derivatives of beta-lactam nuclei and precursors and derivatives thereof

Abstract

A synthesis process of precursors of derivatives of beta-lactam compounds, said beta-lactam compounds being selected from 6-aminopenicillanic acid and 7-aminocephalosporanic acid, preferably 6-aminopenicillanic acid, comprising the following steps: a) protection of the amine group of the beta-lactam compound, selected from 6-aminopenicillanic acid and 7-aminocephalosporanic acid, preferably 6-aminopenicillanic acid, through the formation of a carbamate by reaction with a dicarbonate; b) esterification of the carboxyl group in position 2 of the beta-lactam compound obtained in step a) by reaction with propargyl alcohol.

Claims

1. A synthesis process of triazole derivatives of -lactam compounds, comprising the following steps: a) protection of the amine group of the -lactam compound, selected from a group consisting of 6-aminopenicillanic acid and 7-aminocephalosporanic acid through the formation of a carbamate by reaction with a dicarbonate; b) esterification of the carboxyl group in position 2 of the -lactam compound obtained in step a) by reaction with propargyl alcohol to obtain a precursor; and c) cycloaddition reaction between the precursor obtained in step b) and an organic azide, resulting in the formation of a corresponding triazole derivative of the -lactam compound.

2. The process according to claim 1 wherein step a) is carried out by reaction with an alkyl, aromatic or cyclic dicarbonate.

3. The process according to claim 1, wherein step a) is carried out at room temperature for a time ranging from 10 to 32 hours, in a solvent which is a mixture 1:1 by volume of 1,4-dioxane and water or a mixture 1:1 by volume of tetrahydrofuran (THF) and water, and wherein the dicarbonate is di-(tert-butyl dicarbonate) being present in a molar ratio ranging from 2 to 1 with respect to the -lactam compound.

4. The process according to claim 1 wherein step b) is carried out under anhydrous conditions using an anhydrous solvent selected from a group consisting of diethylether, 1,4-dioxane, dichloromethane (DCM), tetrahydrofuran (THF), THF in a volume ratio of 4/1 with chloroform or anhydrous DCM, in the presence of an anhydrous amine selected from a group consisting of triethylamine and dimethylaminopyridine.

5. The process according to claim 1, wherein step b) is carried out at room temperature for a time ranging from 24 to 52 hours.

6. The process according to claim 1, wherein step c) is a cycloaddition reaction mediated by copper in oxidation state I, wherein the organic azide is selected from a group consisting of tert-butyl 2-azidoethylcarbamate, 2,3,4,6-tetra-O-acetyl--D-glucopyranosyl azide and 2,3,4,6-OH--D-glucopyranosyl azide.

7. The process according to claim 1, wherein step c) is carried out in a mixture of water and C1-C3 alkyl alcohol, at a temperature ranging from 55 to 60 C., for a time ranging from 4 to 10 hours.

8. The process according to claim 1 wherein the -lactam compound is 6-aminopenicillanic acid.

9. The process according to claim 2 wherein the alkyl, aromatic or cyclic dicarbonate is selected from di-tert-butyl dicarbonate, bis(oxyran-2-ylmethyl) dicarbonate, bis(trifluoro-methyl)dicarbonate, bis (2-ethoxycyclohexyl) dicarbonate or dibenzyl dicarbonate.

10. The process according to claim 9 wherein step a) is carried out by reaction with di-tert-butyl dicarbonate.

11. The process according to claim 3 wherein step a) is carried out at room temperature for a time equal to about 24 hours.

12. The process according to claim 3 wherein the di-(tert-butyl dicarbonate) is present in a molar ratio ranging from 1.3 to 1.

13. The process according to claim 5 wherein step b) is carried out at room temperature for a time ranging from 24 to 36 hours.

14. The process according to claim 7 wherein step c) is carried out in 1:1 by volume of water and isopropanol (IPA).

15. The process according to claim 7 wherein step c) is carried out at a temperature ranging from 58 to 60 C.

16. The process according to claim 1 wherein step c) is carried out for a time ranging from 4.5 to 6 hours.

Description

EXAMPLE 1

Synthesis of (2S,5R,6R)-6-(tert-butoxycarbonyl amino)-3,3-dimethyl-7-oxo-4-thio-1-azabicyclo[3.2.0]heptane-2-carboxylic Acid

(1) ##STR00006##

(2) 1 g (4.624 mmoles) of 6-APA was suspended, in a 100 ml flask, in 30 ml of a solution of water and dioxane in a ratio of 1:1 by volume, at room temperature. After the addition of 1.288 ml (9.248 mmoles) of TEA, a complete solubilization was obtained. 1.312 g of di-tert-butyl dicarbonate (6.0112 mmoles) where then added to this solution and the solution was kept under stirring at room temperature for 24 hours.

(3) The reaction trend was monitored by means of thin layer chromatography (TLC) with hexane/acetone 1:1 as solvent and when the starting reagent had been totally consumed, the dioxane was removed by means of evaporation at reduced pressure.

(4) The compound thus obtained was extracted using DCM (350 ml) and the organic phase was dried on NaSO.sub.4. The organic solvent was then removed under vacuum obtaining a white foam with a yield of 90%.

(5) ##STR00007##

(6) .sup.1H-NMR (400 MHz, CDCl.sub.3): 5.51 (d, J=4.2 Hz, H2--lactam, 1H), 5.35 (dd, J=9.9, 3.7 Hz, H3--lactam, 1H), 5.28 (d, J=9.6 Hz, H4--lactam, 1H), 4.27 (br s, H1--lactam, 1H), 1.61 (s, 3H), 1.56 (s, 3H), 1.40 (s, 9H).

(7) .sup.13C-NMR (100 MHz, CDCl3): 174.99 (s, 1C, NCO, C.sub.8-lactam), 172.98 (s, 1C, OCO, C.sub.2-lactam), 154.37 (s, 1C, CO Boc), 80.63 (s, 1C, C(CH.sub.3).sub.3), 73.11 (s, 1C, C.sub.1-lactam), 67.96 (s, 1C, C.sub.7-lactam), 64.68 (s, 1C, C.sub.3-lactam), 59.71 (s, 1C, C.sub.6-lactam), 32.15 (s, 1C, CH.sub.3, C.sub.4-lactam), 28.29 (s, 1C, CH.sub.3 C.sub.5-lactam), 27.60 (s, 3C, C(CH.sub.3).sub.3)

(8) Melting point: 74-76 C.

(9) Chemical Formula: C.sub.13H.sub.20N.sub.2O.sub.5S

(10) Molecular Weight: 316.37

(11) The .sup.1H-NMR .sup.13C-NMR spectra of the compound having formula (II) are indicated in FIGS. 1-4.

EXAMPLE 2

Synthesis of (2S,5R,6R)-prop-2-inyl 6-(tert-butoxy-carbonylamino)-3,3-dimethyl-7-oxo-4-thio-1-azabicyclo-[3.2.0]heptane-2-carboxylate

(12) ##STR00008##

(13) 316.37 mg of (2S,5R,6R)-6-(tert-butoxycarbonyl amino)-3,3-dimethyl-7-oxo-4-thio-1-azabicyclo[3.2.0]-heptane-2-carboxylic acid (1 mmole) and 139 l (1 mmole) of anhydrous TEA (alternatively 175 L of DIPEA can be used (N,N diisopropyl-ethyl amine)) were dissolved in 10 ml of anhydrous Et.sub.2O/anhydrous DCM (CH.sub.2Cl.sub.2) 8/1 (alternatively only DCM, dioxane or THF can be used) at room temperature under an atmosphere of N.sub.2. 190.65 mg (1 mmole) of para-toluenesulfonyl chloride (alternatively 98 L of methanesulfonyl chloride or 144 L of Diethylphosphate chloride can be used) were added to the solution which was then left under stirring at room temperature for 2 hours. The formation of a white solid (if the reaction is carried out in ether) indicates the formation of triethylamine hydrochloride (or DIPEA).

(14) A solution composed of 57.70 ml (1 mmole) of propargyl alcohol and 139 ml (1 mmole) of anhydrous TEA (or alternatively 175 L of DIPEA) was prepared in 3 ml of anhydrous Et.sub.2O (or DCM) and was added to the mixture in a single portion at room temperature. The suspension thus obtained was left under stirring in an inert atmosphere for 48 hours.

(15) The reaction trend was monitored by means of thin layer chromatography (TLC) with hexane/AcOEt 4:1 as solvent (Rf=0.25) and when the starting reagent had been totally consumed, 10 ml of water were added to the reaction mixture, the compound thus obtained was extracted using diethyl ether (315 ml) and the organic phase was dried on NaSO.sub.4. The sticky oil, red-coloured when the activator used is para-toluenesulfonyl chloride or methanesulfonyl chloride, or greenish when the activator used is diethyl phosphate chloride, was purified by means of flash chromatography, obtaining 110 mg of a pale yellow-coloured oil (35% yield).

(16) ##STR00009##

(17) .sup.1H-NMR (400 MHz, CDCl.sub.3): 5.51 (d, J=4.2 Hz, 1H, H2 -lactam), 5.46 (dd, J=8.7, 3.2 Hz, 1H, H3 -lactam), 5.29 (d, J=9.1 Hz, 1H, H4 -lactam), 4.79 (dd, J=15.5, 2.5 Hz, 1H, CH.sub.2), 4.69 (dd, J=15.5, 2.4 Hz, 1H, CH.sub.2), 4.41 (br s, 1H, H1 -lactam), 2.51 (t, J=2.5 Hz, 1H, CH), 1.64 (s, 3H), 1.51 (s, 3H), 1.42 (s, 9H).

(18) .sup.13C-NMR (100 MHz, CDCl3): 174.97 (s, 1C, NCO, C.sub.8-lactam), 167.26 (s, 1C, OCO, C.sub.2-lactam), 154.24 (s, 1C, CO Boc), 81.16 (s, 1C, C(CH.sub.3).sub.3), 76.67 (s, 1C, HCC), 70.62 (s, 1C, HCC), 70.46 (s, 1C, CHCOOR, C.sub.1-lactam), 68.45 (s, 1C, BocNHCCHS, C.sub.7-lactam), 65.04 (s, 1C, C(CH3).sub.2, C.sub.3-lactam), 60.28 (s, 1C, CHNHBoc, C.sub.6-lactam), 52.92 (s, 1C, HCCCH.sub.2), 31.39 (s, 1C, CH.sub.3C.sub.4-lactam), 28.33 (s, 1C, CH.sub.3, C.sub.5-lactam), 27.30 (s, 3C, C(CH.sub.3).sub.3)

(19) Chemical Formula: C.sub.16H.sub.22N.sub.2O.sub.5S

(20) Molecular Weight: 354.42

(21) The .sup.1H-NMR .sup.13C-NMR spectra of the compound having formula (III) are indicated in FIGS. 5-8.

EXAMPLE 3

Synthesis of (2R,3R,4S,5R,6R)-2-(acetoxymethyl)-6-(4-(((2S,5R,6R)-6-(tert-butoxycarbonylamino)-3,3-dimethyl-7-oxo-4-thio-1-azabicyclo[3.2.0]heptane-2-carbonyl-oxy)methyl-1H-1,2,3-triazol-1-yl)tetrahydro-2H-pyran-3,4,5-triyl triacetate

(22) ##STR00010##

(23) 200 mg (0.564 mmoles) of (2S,5R,6R)-prop-2-inyl 6-(tert-butoxycarbonylamino)-3,3-dimethyl-7-oxo-4-thio-1-azabicyclo[3.2.0]heptane-2-carboxylate (1), 232 mg of 2,3,4,6-tetra-O-acetyl--D-glucopyranosyl azide (0.620 mmoles), 7.72 mg of CuSO.sub.4 5H.sub.2O (0.031 mmoles) and 61.38 mg (0.31 mmoles) of sodium ascorbate were suspended in 10 ml of a solution of water and isopropyl alcohol 1:1. The reaction mixture was left under stirring at 60 C. for 4 hours and the reaction trend was monitored by means of thin layer chromatography (TLC) with DCM/Et.sub.2O 9:1 as solvent (Rf=0.7). When the starting reagent had been totally consumed, the alcohol was removed at reduced pressure and the compound was extracted with DCM (315 ml), the organic phase was dried on NaSO.sub.4 giving a pale brown solid which was purified by means of flash chromatography using DCM/Et.sub.2O 9.5:0.5 as solvent, obtaining 120 mg of a white solid (0.165 mmoles) (30% yield).

(24) ##STR00011##

(25) .sup.1H-NMR (400 MHz, CDCl3): 7.89 (s, 1H, H-triazole), 5.86 (d, J=9.1 Hz, 1H, H1-glu), 5.48 5.48 (d, J=4.2 Hz, 1H, H2 -lactam), 5.43 (d, J=9.7 Hz, 1H H3 -lactam) 5.42-5.39 (m, 2H, H3-H2 glu), 5.32-519 (m, 4H, CH.sub.2-tryazole H2 -lactam, H4 glu), 4.38 (s, 1H, H1 -lactam), 4.27 (dd, J=12.7, 4.9 Hz, 1H, H6 glu), 4.12 (dd, J=12.6, 2.0 Hz, 1H, H6 glu), 3.99 (ddd, J=10.1, 4.9, 2.1 Hz, 1H, H5 glu), 2.04 (s, 3H, CH.sub.3CO), 2.03 (s, 3H, CH.sub.3CO), 1.99 (s, 3H, CH.sub.3CO), 1.82 (s, 3H, CH.sub.3CO), 1.58 (s, 3H, CH.sub.3 -lactam), 1.40 (s, 9H, C(CH.sub.3).sub.3), 1.36 (s, 3H, CH.sub.3 -lactam),

(26) .sup.13C-NMR (100 MHz, CDCl3): 174.97 (s, 1C, NCO, C.sub.8-lactam), 170.57, (s, 1C, CH.sub.3CO), 170.00 (s, 1C, CH.sub.3CO), 169.44 (s, 1C, CH.sub.3CO), 168.90 (s, 1C, CH.sub.3CO), 167.73 (s, 1C, OCO, C.sub.2-lactam), 154.24 (s, 1C, CO Boc), 142.61 (s, 1C, C.sub.4-triazole), 122.85 (s, 1C, C.sub.5-triazole), 85.90 (s, 1C, C.sub.1Glu), 81.16 (s, 1C, C(CH.sub.3).sub.3), 75.31 (s, 1C, C.sub.5Glu), 72.53 (s, 1C, C.sub.2Glu), 70.49 (s, 1C, C.sub.1-lactam), 70.38 (s, 1C, C.sub.3Glu), 68.38 (s, 1C, C.sub.7-lactam), 67.69 (s, 1C, C.sub.4Glu), 64.84 (s, 1C, C.sub.3-lactam), 61.53 (s, 1C, C.sub.7Glu), 60.21 (s, 1C, C.sub.6-lactam), 58.25 (s, 1C, CH.sub.2-triazole) 31.36 (s, 1C, C.sub.4-lactam), 28.30 (s, 3C, C(CH.sub.3).sub.3), 27.16 (s, 1C, C.sub.5-lactam), 20.80 (s, 1C, CH.sub.3CO), 20.64 (s, 1C, CH.sub.3CO), 20.61 (s, 1C, CH.sub.3CO), 20.21 (s, 1C, CH.sub.3CO)

(27) Chemical Formula: C.sub.30H.sub.41N.sub.5O.sub.14S

(28) Molecular Weight: 727.74

(29) Melting Point: 147 C.

(30) The .sup.1H-NMR .sup.13C-NMR spectra of the compound having formula (IV) are indicated in FIGS. 9-12.

EXAMPLE 4

Synthesis of 2S,5R,6R)-6-(tert-butoxycarbonylamino)-ethyl)-1H-1,2,3-triazol-4-yl)methyl 6-(tert-butoxy-carbonylamino) 3,3-dimethyl-7-oxo-4-thio-1-azabicyclo-[3.2.0]heptane-2-carboxylate

(31) ##STR00012##

(32) 150 mg (0.4232 mmoles) of (2S,5R,6R)-prop-2-inyl 6-(tert-butoxycarbonylamino)-3,3-dimethyl-7-oxo-4-thio-1-azabicyclo[3.2.0]heptane-2-carboxylate (1), 94.57 mg of tert-butyl 2-azidoethylcarbamate (0.5078 mmoles), 6.33 mg of CuSO.sub.4 5H.sub.2O (0.0254 mmoles) and 50.30 mg (0.254 mmoles) of L(+)sodium ascorbate were suspended in 10 ml of a solution of water and isopropyl alcohol 1:1. The reaction mixture was left under stirring at 60 C. for 4 hours and the reaction trend was monitored by means of thin layer chromatography (TLC) with DCM/Et.sub.2O 9.5:0.5 as solvent (Rf=0.7). When the starting reagent had been totally consumed, the alcohol was removed at reduced pressure and the compound was extracted with DCM (315 ml), the organic phase was dried on NaSO.sub.4 giving a brownish solid which was purified by means of flash chromatography using DCM/Et.sub.2O 9.5:0.5 as solvent, obtaining 90 mg of a pale brown foam (40% yield).

(33) ##STR00013##

(34) .sup.1H-NMR (400 MHz, CDCl3) 7.65, (s, 1H, H-triazole), 5.50 (d, J=4.2 Hz, 1H, H2 -lactam), 5.47 (dd, J=9.4, 4.0 Hz, 1H, H3 -lactam), 5.30 (s, 2H, CH.sub.2-tryazole), 5.27 (d, J=9.9 Hz, 1H, H4 -lactam), 4.87 (s, 1H, Boc-NHCH.sub.2), 4.48 (t, J=5.6 Hz, 2H, Boc-NHCH.sub.2), 4.40 (s, 1H, H1 -lactam), 3.63 (m, 2H, Boc-NH CH.sub.2CH.sub.2), 1.62 (s, 3H, CH.sub.3 -lactam), 1.44 (s, 9H, C(CH.sub.3).sub.3), 1.42 (s, 9H, C(CH.sub.3).sub.3), 1.40 (s, 3H, CH.sub.3 -lactam)

(35) .sup.13C-NMR (100 MHz, CDCl3) 174.99 (s, 1C, NCO, C.sub.8-lactam), 167.94 (s, 1C, OCO, C.sub.2-lactam), 155.93 (s, 1C, CO Boc), 154.24 (s, 1C, CO Boc), 141.88 (s, 1C, C.sub.4-triazole), 125.09 (s, 1C, C.sub.5-triazole), 81.17 (s, 1C, C(CH.sub.3).sub.3), 80.28 (s, 1C, C(CH.sub.3).sub.3), 70.56 (s, 1C, C.sub.1-lactam), 68.43 (s, 1C, C.sub.7-lactam), 64.84 (s, 1C, C.sub.3-lactam), 60.27 (s, 1C, C.sub.6-lactam), 58.48 (s, 1C, CH.sub.2-triazole) 50.20 (s, 1C, Boc-NH CH.sub.2CH.sub.2), 40.60 (s, 1C, Boc-NH CH.sub.2CH.sub.2), 31.43 (s, 1C, C.sub.4-lactam), 28.43 (s, 3C, C(CH.sub.3).sub.3), 28.33 (s, 3C, C(CH.sub.3).sub.3), 27.25 (s, 1C, C.sub.5-lactam),

(36) Chemical Formula: C.sub.23H.sub.36N.sub.6O.sub.7S

(37) Molecular Weight: 540.63

(38) Melting Point: 78-83 C.

(39) The .sup.1H-NMR .sup.13C-NMR spectra of the compound having formula (V) are indicated in FIGS. 13-16.

EXAMPLE 5

Synthesis of (2S,5R,6R)-(1-((2R,3R,4S,5S,6R)-3,4,5-trihydroxy-6-(hydroxymethyl)tetrahydro-2H-pyran-2-yl)-1H-1,2,3-triazol-4-yl)methyl 6-(tert-butoxycarbonyl-amino)-3,3-dimethyl-7-oxo-4-thio-1-azabicyclo[3.2.0]-heptane-2-carboxylate

(40) ##STR00014##

(41) 200 mg (0.564 mmoles) of (2S,5R,6R)-prop-2-inyl 6-(tert-butoxycarbonylamino)-3,3-dimethyl-7-oxo-4-thio-1-azabicyclo[3.2.0]heptane-2-carboxylate (1), 127 mg of 2,3,4,6-tetra-O-acetyl--D-glucopyranosyl azide (0.620 mmoles), 7.72 mg of CuSO.sub.4 5H.sub.2O (0.031 mmoles) and 61.38 mg (0.31 mmoles) of sodium ascorbate were suspended in 10 ml of a solution of water and isopropyl alcohol 1:1. The reaction mixture was left under stirring at 60 C. for 4 hours and the reaction trend was monitored by means of thin layer chromatography (TLC) with DCM/MeOH 9:1 as solvent (Rf=0.6). When the starting reagent had been totally consumed, the solvent was removed under vacuum giving a pale green solid which was analyzed by NMR and not purified.

(42) ##STR00015##

(43) FIGS. 17 and 18 indicate the HSQC (Heteronuclear Single Quantum Correlation) spectrum in deuterated CDCl.sub.3, to support the synthesis of compound (VI): in FIG. 18, in fact, the triangle indicates the carbon of the triazole, the large oval indicates the carbons of the penicillin ring and the CH.sub.2 of propargyl (Blue) which has reacted with the azide. In the small oval, there is the anomeric glucose and in the rectangle, the carbons of sugar: the two blue signs indicate the carbon of CH.sub.2(C-6) of glucose.

(44) In the HSQC, the carbons having only one proton or three protons are normally red-coloured, whereas the carbons having two protons are indicated in blue.

EXAMPLE 6

Synthesis of (6R,7R)-3-(acetoxymethyl)-7-(tert-butoxy-carbonylamino)-6-oxo-5-thio-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic Acid

(45) ##STR00016##

(46) 1 g (3.673 mmoles) of 7-ACA (7-amino-cephalosporanic acid) was suspended, in a 100 ml flask, in 30 ml of a solution of water and dioxane in a ratio of 1:1 by volume, at room temperature. After the addition of 1.023 ml (7.346 mmoles) of TEA, a complete solubilization was obtained. 1.042 g of di-tert-butyl dicarbonate (4.775 mmoles) where then added to this solution and the solution was kept under stirring at room temperature for 24 hours.

(47) The reaction trend was monitored by means of thin layer chromatography (TLC) with DMC/methanol 9.5:0.5 as solvent and when the starting reagent had been totally consumed, the dioxane was removed by means of evaporation at reduced pressure.

(48) The compound thus obtained was extracted using DCM (350 ml) and the organic phase was dried on NaSO.sub.4. The organic solvent was then removed under vacuum obtaining a white foam with a yield of 90%.

(49) The compound thus obtained was extracted using DCM (350 ml) and the organic phase was dried on NaSO.sub.4. The aqueous phase was dried and 0.930 g of a yellow solid were obtained as a mixture of starting material and compound (VII) which was purified by means of flash chromatography obtaining a white solid with a yield of 70%.

(50) ##STR00017##

(51) .sup.1H-NMR (400 MHz, CDCl.sub.3): 13.38 (br, 1H, COOH), 5.53 (dd, J=9.7, 4.7 Hz, 1H, H6--lactam), 5.21 (d, J=9.8 Hz, 1H, H7--lactam), 5.11 (d, J=12.6 Hz, 1H, H1-(-lactam), 4.97 (d, J=4.8 Hz, 1H, H5--lactam), 4.93 (d, J=12.6 Hz, 1H, H2--lactam), 3.51 (d, J=17.8 Hz, 1H, H3--lactam), 3.26 (d, J=17.8 Hz, 1H, H4--lactam), 2.04 (s, 3HCH.sub.3), 1.43 (s, 9H, 3-CH.sub.3).

(52) .sup.13C-NMR (100 MHz, CDCl3): 171.10 (s, 1C, CH.sub.3CO), 166.87 (s, 1C, NCO, C.sub.8-lactam), 164.97 (s, 1C, OCO, C.sub.2-lactam), 154.37 (s, 1C, CO Boc), 132.34, (s, 1C, C.sub.3-lactam), 116.48 (s, 1C, C.sub.1-lactam), 80.98 (s, 1C, C(CH.sub.3).sub.3), 64.35 (s, 1C, C.sub.4-lactam), 60.84 (s, 1C, C.sub.7-lactam), 57.75 (s, 1C, C.sub.6-lactam), 28.32 (s, 3C, C(CH.sub.3).sub.3), 26.65 (s, 1C, C.sub.5-lactam), 21.08 (s, 1C, CH.sub.3CO)

(53) The .sup.1H-NMR .sup.13C-NMR spectra of the compound having formula (VII) are shown in FIGS. 19-23.

EXAMPLE 7

Synthesis of (6R,7R)-prop-2-inyl 3-(acetoxymethyl)-7-(tert-butoxycarboxylamino)-8-oxo-5-thio-1-azabicyclo-[4.2.0]oct-2-ene-2-carboxylate (IX)

(54) ##STR00018##

(55) 372.39 mg of (6R,7R)-3-(acetoxymethyl)-7-(tert-butoxycarboxylamino)-8-oxo-5-thio-1-azabicyclo[4.2.0]-oct-2-ene-2-carboxylic acid (1 mmole) and 139 l (1 mmole) of anhydrous TEA (or alternatively 175 L, of N,N diisopropylethyl amine (DIPEA)) were dissolved in 10 ml of an anhydrous mixture of Et.sub.2O/DCM 7/3 (alternatively in 10 ml of anhydrous dioxane or anhydrous THF or anhydrous DCM) at 0 C. under an atmosphere of N.sub.2. 190.65 mg (1 mmole) of para-toluenesulfonyl chloride (or alternatively 98 L of methanesulfonyl chloride or 144 L of diethylphosphate chloride) were added to the solution which was then left under stirring at room temperature for 2 hours. The formation of a white solid in the case of the mixture of ether and DCM, indicated the formation of hydrochloride of the base.

(56) A solution composed of 57.70 ml (1 mmole) of propargyl alcohol and 139 ml (1 mmole) of anhydrous TEA (or alternatively 175 L of DIPEA) was prepared in 3 ml of anhydrous Et.sub.2O (or alternatively in DCM or anhydrous dioxane) and was added to the mixture in a single portion at room temperature. The suspension thus obtained was left under stirring in an inert atmosphere for 48 hours.

(57) The reaction trend was monitored by means of thin layer chromatography (TLC) with DCM 9.5/Et.sub.2O 0.5 as solvent (Rf=0.5) and when the starting reagent had been totally consumed, 20 ml of water were added to the reaction mixture, the compound thus obtained was extracted using diethyl ether (315 ml) and the organic phase was dried on Na.sub.2SO.sub.4. 400 mg of sticky oil, red-coloured when the activator used is para-toluenesulfonyl chloride or methanesulfonyl chloride, or greenish when the activator used is diethyl phosphate chloride, consists in the desired product (IX) (about 50%) and in the corresponding diastereoisomer X (due to the rearrangement of the double bond). The compound proved to be unstable to a purification by direct-phase flash chromatography and the pure product was still not isolated. NMR (1-H, COSY and .sup.13C) analysis, however, confirms the presence of the desired product as indicated by the relative images. In particular, the presence of two double doublets can be observed at 4.93 ppm and 4.81 ppm with J couplings of 15.6 and 2.5 Hz relating to the two methylene protons of the propargyl introduced. At 2.5, there is the triplet typical of methane CH. The disappearance of the acid proton at 13.38 is equally important to note, indicating the formation of propargylated ester.

(58) ##STR00019##

(59) .sup.1H-NMR (400 MHz, CDCl.sub.3): 5.66 (dd, J=9.7, 4.9 Hz, 1H, H6), 5.21 (d, J=9.8 Hz, 1H, H7), 5.11 (d, J=13.6 Hz, 1H, H1), 4.98 (d, J=4.9 Hz, 1H, H5), 4.93 (dd, J=15.6, 2.5 Hz, 1H, H9), 4.86 (d, J=13.7 Hz, 1H, H2), 4.81 (dd, J=15.6, 2.5 Hz, 1H, H8), 3.59 (d, J=18.5 Hz, 1H, H3), 3.41 (d, J=18.6 Hz, 1H, H4), 2.53 (t, J=2.5 Hz, 1H, H10), 2.09 (s, 3H, CH.sub.3), 1.46 (s, 9H, 3-CH.sub.3).

(60) The non-assigned peaks belong to Compound X: more specifically, the peaks at 5.66, 5.21, 4.98 are the system H6, H7, H5; the system of CH.sub.2 with respect to C9 of the propargyl group is characterized by two double doublets at 4.93 and 4.81 ppm. The value J of 15.6 Hz is coupled with the 2.5 Hz of H10 typical of alkine terminal groups. In accordance with the starting material, the system AB of CH.sub.2 with respect to C5 of the ring with 6 atoms can be observed and two doublets are detected with the same coupling constant at 3.59 and 3.41 ppm. The system AB represented by the two doublets at 5.11 and 4.86 ppm can also be observed. This is the CH.sub.2 of the C4. The signal at 2.5 pm is the triplet of H10, which has crossed peaks (in COSY NMR) with the CH.sub.2 system represented by the two doublets at 4.93 and 4.81 ppm.

(6R,7R)-prop-2-inyl 3-(acetoxymethyl)-7-(tert-butoxy-carboxyamino)-8-oxo-5-thio-1-azabicyclo[4.2.0]oct-3-ene-2-carboxylate (X)

(61) ##STR00020##

(62) .sup.1H-NMR (400 MHz, CDCl.sub.3): 6.48 (d, J=1.3 Hz, 1H, H4), 5.46 (dd, J=8.8, 3.2 Hz, 1H, H6), 5.34 (d, J=8.7 Hz, 1H, H7), 5.25 (d, J=3.9 Hz, 1H, H5), 5.06 (d, J=1.4 Hz, 1H, H1), 4.76 (m, 2H, H9-H8), 4.68 (d, J=12.8 Hz, 1H, H2), 4.62 (d, J=12.7 Hz, 1H, H3), 2.54 (t, J=2.4 Hz, 1H, H10) 2.07 (s, 3H, CH.sub.3), 1.45 (s, 9H).

(63) In particular, the disappearance of the proton at 13 ppm indicates that the esterification of the carboxyl group has taken place, whereas the presence of the proton at 6.48 ppm (H4) indicates that the double bond has been rearranged: this proton is a doublet with a coupling constant with H1 of 1.4-1.5 Hz. The presence of the multiplet at 4.76 ppm, which integrates 2, indicates the H9-H8 of the system of the propargyl group. In COSY, in fact, a crossed peak with the proton at 2.5 ppm (H10) is present. The two doublets with the same coupling constant J equal to 12.7 Hz are the signals of H2-H3; the impurities are therefore precisely the signals of the compound IX described above.

(64) The .sup.1H-NMR spectra of the compound having formula (IX) are indicated in FIGS. 24-27, whereas the .sup.1H-NMR spectra of the compound having formula (X) are indicated in FIGS. 28-29.