Dental materials based on low-odour thiols

Abstract

Dental material, which contains an ene compound with two or more CC multiple bonds and a thiol according to general Formula (1) or an oligomer based on such a thiol, ##STR00001##
wherein n, p and m are chosen such that the thiol has a total of at least 3 SH groups.

Claims

1. Dental material, which contains at least one thiol and at least one ene compound with two or more CC multiple bonds, characterized in that it contains at least one thiol according to general Formula (1), ##STR00023## in which R is SO.sub.2, a linear or branched aliphatic C.sub.1-20 radical, an aromatic C.sub.6-20 radical, a cycloaliphatic C.sub.3-18 radical or a heterocyclic radical with 3 to 17 C atoms and 1 to 3 heteroatoms which are selected from N, O and S; R.sup.1 is absent or is a linear or branched aliphatic C.sub.1-12 radical, an aromatic C.sub.6-20 radical, a cycloaliphatic C.sub.3-18 radical or a heterocyclic radical with 3 to 17 C atoms and 1 to 3 heteroatoms which are selected from N, O and S; R.sup.2 is absent or is a linear or branched aliphatic C.sub.1-20 radical which can be interrupted by O or S, an aromatic C.sub.6-10 radical which can be substituted by CH.sub.3, CH.sub.2CH.sub.3, OH, OCH.sub.3 or OCOCH.sub.3; R.sup.3 is absent or is a linear or branched aliphatic C.sub.1-20 radical which can be interrupted by O or S, an aromatic C.sub.6-10 radical which can be substituted by CH.sub.3, CH.sub.2CH.sub.3, OH, OCH.sub.3 or OCOCH.sub.3; R.sup.4 is a C.sub.1-6 alkyl radical; X, Y independently of each other are O, S, CONH, OCONH or NHCONH or are absent; Z is O, S, CONH, OCONH or NHCONH or is absent; m is an integer from 1 to 4; n is an integer from 1 to 4; p is an integer from 1 to 6; q is an integer from 0 to 4, wherein n, p and m are chosen such that the thiol has a total of at least 3 SH groups.

2. Dental material according to claim 1, in which the variables of Formula 1 have the following meanings: R is SO.sub.2, a linear or branched aliphatic C.sub.1-12 radical, an aromatic C.sub.6-18 radical, a cycloaliphatic C.sub.5-8 radical or a heterocyclic radical with 3 to 5 C atoms, 1 to 3 heteroatoms and a total of 5-8 ring atoms, wherein the heteroatoms are selected from N, O and S; R.sup.1 is absent, a linear or branched aliphatic C.sub.1-10 radical or an aromatic C.sub.6-10 radical; R.sup.2 is absent or is a linear or branched aliphatic C.sub.1-10 radical or a phenyl radical; R.sup.3 is a linear or branched aliphatic C.sub.1-10 radical or a phenyl radical; R.sup.4 is a C.sub.1-4 alkyl radical; X is O or is absent; Y is O or is absent; Z is O or is absent; m is 1, 2 or 3; n is 1 or 2; p is 1, 2 or 3; q is 0, 1 or 2.

3. Dental material according to claim 2, in which the variables of Formula 1 have the following meanings: R is SO.sub.2, a linear or branched aliphatic C.sub.1-6 radical, an aromatic C.sub.6 radical, a cycloaliphatic C.sub.5-8 radical or a 1,3,5-triazine-2,4,6-trione radical; R.sup.1 is absent, a linear or branched aliphatic C.sub.1-6 radical or a phenyl radical; R.sup.2 is absent or is a linear or branched aliphatic C.sub.1-3 radical; R.sup.3 is a linear or branched aliphatic C.sub.2-6 radical; R.sup.4 is a C.sub.1-3 alkyl radical; X is O or is absent; Y is O or is absent; Z is O or is absent; m is 2 or 3; n is 1; p is 1 or 2; q is 0 or 1.

4. Dental material according to claim 3, in which the thiol of general Formula (1) is present as reaction product with a di- or multi-functional acrylate or acrylamide or with a di- or multi-functional isocyanate.

5. Dental material according to claim 4, which contains a vinyl, allyl or norbornene compound or an alkyne as ene compound.

6. Dental material according to claim 5, which contains as ene compound a vinyl ether, vinyl ester or an N-vinyl amide; and/or an allyl ether of tri- or higher-functionalized alcohols or a reaction product of tri- or higher-functionalized carboxylic acids with allyl alcohol or allyl amine, a triallyl amine or triallyl-1,3,5-triazine-2,4,6-trione (TATATO); and/or an ester of 5-norbornene-2-carboxylic acid with tri- or higher-functionalized alcohols or an ester of 5-norbornene-2-methanol with tri- or higher-functionalized carboxylic acids; and/or an ester of propargyl alcohol with tri- or higher-functionalized carboxylic acids or an ether of propargyl alcohol with tri- or higher-functionalized alcohols.

7. Dental material according to claim 6, which additionally contains at least one mono- or multi-functional methacrylate or a mixture thereof.

8. Dental material according to claim 7, which additionally contains an initiator for the radical polymerization.

9. Dental material according to claim 8, which additionally contains organic or inorganic particulate filler.

10. Dental material according to claim 9, which contains the following components: a) 5 to 40 wt.-% of at least one thiol of general Formula I or an oligomer thereof, b) 5 to 40 wt.-% of at least one ene component, c) 0 to 40 wt.-% methacrylate(s), d) 0.01 to 10 wt.-% initiator(s), e) 10 to 85 wt.-% filler(s), and f) 0 to 10 wt.-% additive(s).

11. Dental material according to claim 1 for intraoral use as dental cement, filling composite or veneering material.

12. Process of using the dental material according to claim 1 for preparing an inlay, onlay, crown or bridge comprising forming the inlay, onlay, crown or bridge with the dental material and curing the dental material.

13. Process for preparing an oligomeric thiol, in which a thiol of Formula (I) in a stoichiometric excess is reacted with a di- or multi-functional ene compound or with a di- or multi-functional isocyanate wherein Formula (I) comprises ##STR00024## in which R is SO.sub.2, a linear or branched aliphatic C.sub.1-20 radical, an aromatic C.sub.6-20 radical, a cycloaliphatic C.sub.3-18 radical or a heterocyclic radical with 3 to 17 C atoms and 1 to 3 heteroatoms which are selected from N, O and S; R.sup.1 is absent or is a linear or branched aliphatic C.sub.1-12 radical, an aromatic C.sub.6-20 radical, a cycloaliphatic C.sub.3-18 radical or a heterocyclic radical with 3 to 17 C atoms and 1 to 3 heteroatoms which are selected from N, O and S; R.sup.2 is absent or is a linear or branched aliphatic C.sub.1-20 radical which can be interrupted by O or S, an aromatic C.sub.6-10 radical which can be substituted by CH.sub.3, CH.sub.2CH.sub.3, OH, OCH.sub.3 or OCOCH.sub.3; R.sup.3 is absent or is a linear or branched aliphatic C.sub.1-20 radical which can be interrupted by O or S, an aromatic C.sub.6-10 radical which can be substituted by CH.sub.3, CH.sub.2CH.sub.3, OH, OCH.sub.3 or OCOCH.sub.3; R.sup.4 is a C.sub.1-6 alkyl radical; X, Y independently of each other are O, S, CONH, OCONH or NHCONH or are absent; Z is O, S, CONH, OCONH or NHCONH or is absent; m is an integer from 1 to 4; n is an integer from 1 to 4; p is an integer from 1 to 6; q is an integer from 0 to 4, wherein n, p and m are chosen such that the thiol has a total of at least 3 SH groups.

14. Process according to claim 13, in which the thiol of Formula (I) is reacted with a di- or multi-functional acrylate, di- or multi-functional acrylamide or di- or multi-functional isocyanate in a molar ratio of SH to acryl or NCO groups of from 1.5:1 to 15:1.

15. Oligomeric thiol, which is obtainable using a process comprising reacting a thiol of Formula (I) in a stoichiometric excess with a di- or multi-functional ene compound or with a di- or multi-functional isocyanate wherein Formula (I) comprises ##STR00025## in which R is SO.sub.2, a linear or branched aliphatic C.sub.1-20 radical, an aromatic C.sub.6-20 radical, a cycloaliphatic C.sub.3-18 radical or a heterocyclic radical with 3 to 17 C atoms and 1 to 3 heteroatoms which are selected from N, O and S; R.sup.1 is absent or is a linear or branched aliphatic C.sub.1-12 radical, an aromatic C.sub.6-20 radical, a cycloaliphatic C.sub.3-18 radical or a heterocyclic radical with 3 to 17 C atoms and 1 to 3 heteroatoms which are selected from N, O and S; R.sup.2 is absent or is a linear or branched aliphatic C.sub.1-20 radical which can be interrupted by O or S, an aromatic C.sub.6-10 radical which can be substituted by CH.sub.3, CH.sub.2CH.sub.3, OH, OCH.sub.3 or OCOCH.sub.3; R.sup.3 is absent or is a linear or branched aliphatic C.sub.1-20 radical which can be interrupted by O or S, an aromatic C.sub.6-10 radical which can be substituted by CH.sub.3, CH.sub.2CH.sub.3, OH, OCH.sub.3 or OCOCH.sub.3; R.sup.4 is a C.sub.1-6 alkyl radical; X, Y independently of each other are O, S, CONH, OCONH or NHCONH or are absent; Z is O, S, CONH, OCONH or NHCONH or is absent; m is an integer from 1 to 4; n is an integer from 1 to 4; p is an integer from 1 to 6; q is an integer from 0 to 4, wherein n, p and m are chosen such that the thiol has a total of at least 3 SH groups.

16. Dental material according to claim 8, in which the initiator comprises a photoinitiator.

17. Dental material according to claim 9, which contains the following components: a) 5 to 30 wt.-% of at least one thiol of general Formula I or an oligomer thereof, b) 5 to 30 wt.-% of at least one ene component, c) 2 to 30 wt.-% methacrylate(s), d) 0.1 to 3.0 wt.-% initiator(s), e) 10 to 85 wt.-% filler(s), and f) 0 to 5 wt.-% additive(s).

18. Dental material according to claim 9, which contains the following components: a) 5 to 20 wt.-% of at least one thiol of general Formula I or an oligomer thereof, b) 5 to 20 wt.-% of at least one ene component, c) 4 to 20 wt.-% methacrylate(s), d) 0.1 to 3.0 wt.-% initiator(s), e) 10 to 85 wt.-% filler(s), and f) 0 to 5 wt.-% additive(s).

19. Process according to claim 14, in which the molar ratio of SH to acryl or NCO groups is from 1.5:1 to 9:1.

Description

EMBODIMENT EXAMPLES

Example 1

Synthesis of a Tetrathiol-Functionalized Bisphenol a Derivative by Radical Addition of Thioacetic Acid on an Allyl Precursor

a) Synthesis of 2,2-bis[3-(3-acetylmercaptopropyl)-4-(3-acetylmercaptopropoxy)-phenyl]propane

(1) ##STR00015##

(2) 29.14 g (75 mmol) 2,2-bis[3-allyl-4-allyloxyphenyl]propane, which is available according to instructions known in the literature (cf. patent WO 98/58294 A1; M. Abraham, I. Hamerton, J. Rose, J. Grate, J. Chem. Soc. Perkin Trans. 2 (1991) 1417-1423) from bisphenol A and allyl bromide by means of Williamson ether synthesis and Claisen rearrangement, 34.25 g (450 mmol) thioacetic acid and 2.46 g (15 mmol) 2,2-azobis(2-methylpropionitrile) in 200 mL tetrahydrofuran were introduced into a 500-mL three-necked flask. The reaction solution was rinsed with nitrogen for 30 min and then stirred under nitrogen atmosphere for 16 hours at 65 C. After cooling of the reaction solution in an ice bath, 100 mL of a one molar sodium carbonate solution was added dropwise. After extraction with dichloromethane three times, the combined organic phases were washed twice with a one molar sodium hydroxide solution as well as saturated sodium chloride solution, dried over magnesium sulphate and freed from the solvent on a rotary evaporator under reduced pressure. The crude product was purified by column chromatography over silica gel in order to obtain 35.8 g (51.7 mmol, 69% theoretical) 2,2-bis[3-(3-acetylmercaptopropyl)-4-(3-acetylmercaptopropoxy)-phenyl]propane as a yellow, highly viscous oil.

(3) .sup.1H NMR (300 MHz, CDCl.sub.3, [ppm]): 7.02-6.92 (m, 4H, ArH), 6.69 (d, .sup.3J.sub.HH=8.5 Hz, 2H, ArH), 3.98 (t, .sup.3J.sub.HH=5.9 Hz, 4H, OCH.sub.2), 3.07 (t, .sup.3J.sub.HH=7.1 Hz, 4H, CH.sub.2S), 2.85 (t, .sup.3J.sub.HH=7.2 Hz, 4H, CH.sub.2S), 2.63 (m, 4H, ArCH.sub.2), 2.34 and 2.32 (s, 12H, CH.sub.3), 2.14-2.01 (m, 4H, CH.sub.2), 1.90-1.75 (m, 4H, CH.sub.2), 1.61 (s, 6H, C(CH.sub.3).sub.2);

(4) .sup.13C NMR (75 MHz, CDCl.sub.3, [ppm]): 196.01 and 195.81 (S(CO)CH.sub.3), 154.50 (ArC), 143.08 (ArC), 128.98 (ArC), 128.90 (ArC), 125.39 (ArC), 110.48 (ArC), 66.12 (ArOCH.sub.2), 41.75 (C(CH.sub.3).sub.2), 31.26 (C(CH.sub.3).sub.2), 30.80 (S(CO)CH.sub.3), 29.98 (CH.sub.2), 29.83 (CH.sub.2), 29.64 (CH.sub.2), 29.05 (CH.sub.2), 26.24 (CH.sub.2);

(5) FTIR: =2962 (w), 2926 (w), 2867 (w), 1685 (s, .sub.C=O), 1607 (w), 1500 (s), 1470 (m), 1415 (m), 1410 (m), 1383 (w), 1353 (m), 1294 (w), 1243 (s), 1131 (s), 1105 (s), 1038 (m), 953 (s) cm.sup.1;

(6) MALDI-TOF MS: m/z.sub.found: 692.2 (M.sup.+), 715.2 (M+Na.sup.+), 731.2 (M+K.sup.+), m/z.sub.calculated: 715.22 (M+Na.sup.+).

b) Synthesis of 2,2-bis[3-(3-mercaptopropyl)-4-(3-mercaptopropoxy)phenyl]-propane

(7) ##STR00016##

(8) 35.69 g (51.50 mmol) 2,2-bis[3-(3-acetylmercaptopropyl)-4-(3-acetylmercaptopropoxy)-phenyl]propane, 22.17 g conc. hydrochloric acid (37 wt.-%) in a mixture of 200 mL methanol and 50 mL tetrahydrofuran were introduced into a 500-mL three-necked flask. The reaction solution was rinsed thoroughly with nitrogen for 30 min and then stirred under a nitrogen atmosphere for 20 hours at 60 C. After cooling to room temperature, 150 mL distilled water was added. After extraction with dichloromethane three times, the combined organic phases were washed twice with a one molar sodium hydroxide solution as well as saturated sodium chloride solution, dried over magnesium sulphate and freed from the solvent on a rotary evaporator under reduced pressure. The crude product was purified by column chromatography over silica gel in order to obtain 20.8 g (39.6 mmol, 76% theoretical) 2,2-bis[3-(3-mercaptopropyl)-4-(3-mercaptopropoxy)phenyl]-propane as a highly viscous oil after drying in a fine vacuum.

(9) .sup.1H NMR (300 MHz, CDCl.sub.3, [ppm]): 7.02 (dd, .sup.3J.sub.HH=8.6 Hz/.sup.4J.sub.HH=2.5 Hz, 2H, ArH), 6.94 (d, .sup.4J.sub.HH=2.5 Hz, 2H, ArH), 6.73 (d, .sup.3J.sub.HH=8.5 Hz, 2H, ArH), 4.04 (t, .sup.3J.sub.HH=5.8 Hz, 4H, OCH.sub.2), 2.79-2.70 (m, 4H, CH.sub.2SH), 2.69-2.61 (m, 4H, ArCH.sub.2), 2.53-2.42 (m, 4H, CH.sub.2SH), 2.14-2.03 (m, 4H, CH.sub.2), 1.90-1.77 (m, 4H, CH.sub.2), 1.61 (s, 6H, C(CH.sub.3).sub.2), 1.40 (t, .sup.3J.sub.HH=8 0.1 Hz, 2H, SH), 1.34 (t, .sup.3J.sub.HH=7.8 Hz, 2H, SH);

(10) .sup.13C NMR (75 MHz, CDCl.sub.3, [ppm]): 154.54 (ArC), 143.05 (ArC), 129.08 (ArC), 129.04 (ArC), 125.22 (ArC), 110.52 (ArC), 65.55 (OCH.sub.2), 41.74 (C(CH.sub.3).sub.2), 34.30 (CH.sub.2), 33.65 (CH.sub.2), 31.26 (C(CH.sub.3).sub.2) 29.42 (CH.sub.2), 24.45 (CH.sub.2), 21.62 (CH.sub.2);

(11) FTIR: =3050 (w), 3025 (w), 2961 (m), 2925 (m), 2867 (w), 2560 (w, .sub.SH), 1606 (w), 1499 (s), 1468 (m), 1439 (m), 1383 (w), 1360 (w), 1294 (m), 1242 (s), 1181 (m), 1154 (m), 1117 (m), 1034 (m), 810 (s) cm.sup.1; MS (EI) m/z (%): 525 (12) [M.sup.+], 524 (36) [M.sup.+], 511 (21), 510 (30), 509 (100), 450 (18), 437 (13), 436 (20), 435 (78), 362 (17), 361 (76), 327 (12), 287 (25), 213 (19), 209 (28), 207 (10), 193 (18), 179 (12), 175 (34), 159 (26), 147 (35), 135 (21), 133 (11), 119 (16), 107 (12), 75 (12), 47 (14), 41 (19);

(12) Elemental Analysis

(13) calculated for C.sub.27H.sub.40O.sub.2S.sub.4: C, 61.79; H, 7.68; S, 24.44.

(14) found: C, 61.99; H, 7.62; S, 24.65.

Example 2

Synthesis of a Tetrathiol-Functionalized Bisphenol A Derivative by Using the Radical Addition of Thioacetic Acid on Propargyl Groups

a) Synthesis of 2,2-bis[4-(2,3-diacetylmercaptopropoxy)-phenyl]propane

(15) ##STR00017##

(16) 10.65 g (35 mmol) 2,2-bis[4-(prop-2-yn-1-yloxy)phenyl]propane, which is available by a Williamson ether synthesis from bisphenol A and propargyl bromide, 26.64 g (350 mmol) thioacetic acid, 1.38 g (8.4 mmol) 2,2-azobis(2-methylpropionitrile) and 150 mL toluene were introduced into a 250-mL three-necked flask. The reaction solution was rinsed thoroughly with nitrogen for 30 min and then stirred under a permanent nitrogen atmosphere for 24 hours at 65 C. After removal of the volatile components under reduced pressure, the crude product was purified by column chromatography over silica gel. In this way, 16.0 g (26.3 mmol, 75% theoretical) 2,2-bis[4-(2,3-diacetylmercaptopropoxy)phenyl]propane was obtained as a highly viscous yellow oil.

(17) .sup.1H NMR (300 MHz, CDCl.sub.3, [ppm]): 7.10 (d, .sup.3J.sub.HH=8.9 Hz, 4H, ArH), 6.78 (d, .sup.3J.sub.HH=8.9 Hz, 4H, ArH), 4.20-4.10 (m, 2H, CH), 4.05-3.94 (m, 4H, OCH.sub.2), 3.45-3.19 (m, 4H, CH.sub.2S), 2.33 (s, 3H, CH.sub.3), 2.32 (s, 3H, CH.sub.3), 1.60 (s, 6H, C(CH.sub.3).sub.2);

(18) .sup.13C NMR (75 MHz, CDCl.sub.3, [ppm]): 194.70 (S(CO)CH.sub.3), 194.61 (S(CO)CH.sub.3), 156.25 (ArC4), 143.85 (ArC1), 127.92 (ArC2,C6) 114.16 (ArC3,C5), 68.73 (ArOCH.sub.2), 43.52 (CH), 41.88 (C(CH.sub.3).sub.2) 31.16 (CH.sub.2S), 30.79 (C(CH.sub.3).sub.2) 30.68 (CH.sub.3), 30.58 (CH.sub.3);

(19) FTIR: =3035 (m), 2966 (m), 2930 (m), 2861 (m), 1688 (s, .sub.C=O), 1607 (m, .sub.C=C), 1582 (w, .sub.C=C), 1508 (s, .sub.C=C), 1463 (m), 1410 (m), 1383 (m), 1353 (m), 1297 (m), 1237 (s), 1181 (s), 1127 (s), 1105 (s) cm.sup.1;

(20) MALDI-TOF MS: m/z.sub.found: 631.1 [M+Na.sup.+]; m/z.sub.calculated: 631.13 [M+Na.sup.+].

b) Synthesis of 2,2-bis[4-(2,3-dimercaptopropoxy)phenyl]propane

(21) ##STR00018##

(22) 14.92 g (24.50 mmol) 2,2-bis[4-(2,3-diactylmercaptopropoxy)-phenyl]propane was dissolved in 40 mL THF in a 250-mL two-necked flask and continuously rinsed thoroughly with nitrogen. The dropwise addition of 60 mL of a potassium methoxide solution (25 wt.-%) took place in an ice bath at 0 C. After addition was complete, the solution was stirred for a further 30 min in an ice bath and then added to 100 mL of a 1N ice-cold HCl solution. The suspension was transferred to a separating funnel and shaken out three times with dichloromethane. The combined organic phases were washed with 100 mL saturated sodium chloride solution, dried over MgSO.sub.4 and freed from the solvent. The crude product was purified by column chromatography over silica gel in order to obtain 6.5 g (14.7 mmol, 60% theoretical) 2,2-bis[4-(2,3-dimercaptopropoxy)-phenyl]propane as a colourless solid. Melting point: 85 C.;

(23) .sup.1H NMR (300 MHz, CDCl.sub.3, [ppm]): 7.13 (d, .sup.3J.sub.HH=8.9 Hz, 4H, ArH), 6.80 (d, .sup.3J.sub.HH=8.9 Hz, 4H, ArH), 4.17 (dd, .sup.3J.sub.HH=4.7 Hz/.sup.2J.sub.HH=9.6 Hz, 2H, ArOCHH), 4.02 (dd, .sup.3J.sub.HH=7.3 Hz/.sup.2J.sub.HH=9.6 Hz, 2H, ArOCHH), 3.32-3.20 (m, 2H, CH), 3.00-2.92 (m, 4H, CH.sub.2SH), 1.95 (d, .sup.3J.sub.HH=9.2 Hz, 2H, 1.65-1.56 (m, 8H, C(CH.sub.3).sub.2 and CH.sub.2SH);

(24) .sup.13C NMR (75 MHz, CDCl.sub.3, [ppm]): 156.23 (ArC4), 143.91 (ArC1), 128.01 (ArC2,C6), 114.21 (ArC3,C5), 70.19 (ArOCH.sub.2), 41.93 (C(CH.sub.3).sub.2), 41.70 (CH), 31.21 (C(CH.sub.3).sub.2) 29.98 (CH.sub.2SH);

(25) FTIR: =3060 (w), 3036 (w), 2962 (m), 2932 (m), 2866 (m), 2557 (m, .sub.SH), 1607 (m), 1581 (w), 1508 (s), 1455 (s), 1414 (m), 1378 (m), 1362 (m), 1300 (s), 1232 (s), 1180 (s) cm.sup.1;

(26) MS (EI) m/z (%): 440 (3) [M.sup.+], 228 (32), 214 (15), 213 (100), 135 (12), 73 (13).

Example 3

Synthesis of a Thiol Resin by Addition of a Trithiol-Functional Precursor on 1,4-butanediol diacrylate or tricyclo-[5.2.1.0(2.6)]decanedimethylol-diacrylate (TCD-DA)

a) Synthesis of 1,3,5-tris(3-acetylmercaptopropyl)-1,3,5-triazine-2,4,6-trione

(27) ##STR00019##

(28) In a 500-mL three-necked flask, 37.39 g (150 mmol) 1,3,5-triallyl-1,3,5-triazine-2,4,6-trione, 41.10 g (540 mmol) thioacetic acid and 3.69 g (22.5 mmol) 2,2-azobis(2-methylpropionitrile) were dissolved in 250 mL tetrahydrofuran analogously to U.S. Pat. No. 4,266,055. The reaction solution was rinsed thoroughly with nitrogen for 30 min and then heated under nitrogen atmosphere for 16 hours at 65 C. After cooling of the reaction solution in an ice bath to 0 C., 100 mL of a one molar sodium carbonate solution was added dropwise. After extraction with dichloromethane three times, the combined organic phases were washed with 80 mL of a one molar sodium hydroxide solution as well as saturated sodium chloride solution, dried over magnesium sulphate and freed from the solvent on a rotary evaporator under reduced pressure. The crude product was recrystallized three times from 200 mL methanol in order to obtain 1,3,5-tris(3-acetylmercaptopropyl)-1,3,5-triazine-2,4,6-trione (48.0 g, 100.5 mmol, 67% theoretical) as a colourless and odourless solid. Melting point: 66-67 C.;

(29) .sup.1H NMR (300 MHz, CDCl.sub.3, [ppm]): 3.89 (t, .sup.3J.sub.HH=7.1 Hz, 6H, NCH.sub.2), 2.83 (t, .sup.3J.sub.HH=7.1 Hz, 6H, CH.sub.2S), 2.26 (s, 9H, CH.sub.3), 1.87 (quint., .sup.3J.sub.HH=7.1 Hz, 6H, CH.sub.2);

(30) .sup.13C NMR (75 MHz, CDCl.sub.3, [ppm]): 195.45 (S(CO)CH.sub.3), 149.03 (CO), 42.07 (NCH.sub.2), 30.68 (CH.sub.3), 28.03 (CH.sub.2), 26.27 (CH.sub.2S);

(31) FTIR: =3024 (w), 2977 (m), 2945 (w), 2923 (w), 1692 (s, .sub.C=O), 1676 (s, .sub.C=O), 1508 (w), 1457 (s), 1425 (s), 1373 (m), 1352 (m), 1338 (m), 1327 (m), 1307 (m), 1296 (w), 1283 (w), 1242 (w), 1135 (s), 1107 (s), 1045 (w), 955 (m), 763 (s, .sub.C-S) cm.sup.1;

(32) MS (EI) m/z (%): 519 (4) [M+], 477 (16), 476 (32), 444 (12), 434 (14), 402 (26), 400 (12), 390 (11), 360 (24), 358 (22), 348 (42), 326 (12), 314 (12), 306 (50), 272 (40), 184 (16), 130 (23), 96 (10), 87 (19), 56 (15), 55 (17), 43 (100), 41 (10).

b) Synthesis of 1,3,5-tris(3-mercaptopropyl)-1,3,5-triazine-2,4,6-trione

(33) ##STR00020##

(34) In a 500-mL three-necked flask, 44.89 g (94 mmol) 1,3,5-tris(3-acetylmercaptopropyl)-1,3,5-triazine-2,4,6-trione was dissolved in a mixture of 190 mL methanol and 60 mL 1,4-dioxane. This solution was rinsed thoroughly with nitrogen for 30 min and then 29.43 g concentrated hydrochloric acid solution (37 wt.-%) was added. The reaction solution was stirred under a nitrogen atmosphere for 20 hours at 60 C. After cooling to room temperature, 200 mL distilled water was added and the aqueous phase was extracted three times with dichloromethane. The combined organic phases were washed with two times 100 mL saturated sodium hydrogen carbonate solution as well as sodium chloride solution, dried over magnesium sulphate and freed from the solvent after filtration on a rotary evaporator under reduced pressure. 32.2 g (91.6 mmol, 97% theoretical) 1,3,5-tris(3-mercaptopropyl)-1,3,5-triazine-2,4,6-trione was obtained as a low-odour, colourless oil (zero shear viscosity at 25 C.: approx. 5 Pa*s). A further reduction in odour was possible by filtration over silica gel.

(35) .sup.1H NMR (300 MHz, CDCl.sub.3, [ppm]): 4.01 (t, .sup.3J.sub.HH=7.0 Hz, 6H, NCH.sub.2), 2.56 (dt, .sup.3J.sub.HH=6.9 Hz/.sup.3J.sub.HH=8.0 Hz, 6H, CH.sub.2S), 1.97 (quint., .sup.3J.sub.HH=7.0 Hz, 6H, CH.sub.2), 1.54 (t, .sup.3J.sub.HH=8.0 Hz, 6H, CH.sub.2SH);

(36) .sup.13C NMR (75 MHz, CDCl.sub.3, [ppm]): 149.10 (CO), 41.91 (NCH.sub.2), 31.94 (CH.sub.2), 22.03 (CH.sub.2SH);

(37) FTIR: =2963 (w), 2933 (w), 2857 (w), 2568 (w, .sub.SH), 1671 (s, .sub.C=O), 1502 (w), 1454 (s), 1422 (s), 1374 (m), 1334 (m), 1318 (m), 1288 (m), 1258 (m), 762 (s, .sub.C-S) cm.sup.1;

(38) MS (EI) m/z (%): 351 (22) [M.sup.+], 319 (19), 318 (85), 317 (34), 286 (17), 284 (100), 244 (20), 224 (25), 210 (49), 170 (27), 127 (21), 84 (29), 70 (41), 56 (77), 47 (22), 41 (35);

(39) Elemental Analysis

(40) calculated for C.sub.12H.sub.21N.sub.3O.sub.3S.sub.3: C, 41.00; H, 6.02; N, 11.95; S, 27.37.

(41) found: C, 41.02; H, 5.92; N, 11.84; S, 27.48.

c) Thiol-Michael Addition of 1,4-butanediol diacrylate and 1,3,5-tris(3-mercaptopropyl)-1,3,5-triazine-2,4,6-trione

(42) ##STR00021##

(43) In a 10-mL microwave pressure vial with a septum, 1.05 g (3 mmol) 1,3,5-tris(3-mercaptopropyl)-1,3,5-triazine-2,4,6-trione and 148.5 mg (0.75 mmol) 1,4-butanediol diacrylate were homogenized under an argon atmosphere. 50 mg triethylamine was added as catalyst, and the reaction mixture was stirred at 50 C. for 24 hours. The triethylamine was entrained out by multiple dissolution in dichloromethane. The addition product was obtained as a colourless oil without a perceptible odour. The odour signature did not change even after storage in a refrigerator over a period of 6 months. Gel permeation chromatography tests in tetrahydrofuran as mobile solvent showed, in addition to the still present monomer 1,3,5-tris(3-mercaptopropyl)-1,3,5-triazine-2,4,6-trione (n=0), the dimer (n=1) and trimer (n=2) as main products in addition to a small proportion of higher homologues.

d) Thiol-Michael Addition of tricyclo[5.2.1.0(2.6)]decanedimethyloldiacrylate (TCD-DA) and 1,3,5-tris(3-mercapotopropyl)-1,3,5-triazine-2,4,6-trione

(44) ##STR00022##

(45) In a 100-mL Schlenk flask, 12.02 g (34.20 mmol) 1,3,5-tris(3-mercaptopropyl)-1,3,5-triazine-2,4,6-trione, 2.60 g (8.55 mmol) tricyclo[5.2.1.0(2.6)]decanedimethyloldiacrylate (TCD-DA) were dissolved in 25 mL tetrahydrofuran. The solution was rinsed thoroughly with nitrogen for 30 min, then 2 mL (1.46 g) triethylamine was added. The reaction solution was stirred at 40 C. for 17 hours and then added to 100 mL of a one molar hydrochloric acid solution. The aqueous phase was extracted three times with dichloromethane. The combined organic phases were then washed with in each case two times 100 mL of a one molar hydrochloric acid solution and a saturated sodium chloride solution, dried over magnesium sulphate, filtered and freed from the solvent on a rotary evaporator under reduced pressure. The addition product was obtained in quantitative yields as an almost odourless, colourless oil, which displayed no change in odour after storage in a refrigerator over a period of 4 months. Gel permeation chromatography tests in tetrahydrofuran as mobile solvent showed, in addition to the still present monomer 1,3,5-tris(3-mercaptopropyl)-1,3,5-triazine-2,4,6-trione (n=0), the dimer (n=1) and trimer (n=2) as main products in addition to a small proportion of higher homologues. (Zero shear viscosity at 25 C.: approx. 113 Pa*s).

Example 4

Filling Composite Based on Thiol-Ene Cross-Linkers

(46) Composite material A and reference A and B (values in mass-%) were prepared according to the Table 1 given below. For this, the reactive components (thiol and ene components) were homogenized together with the stabilizer and the initiator in a Speedmixer centrifugal mixer (from Hauschild) at 1000 RPM for 60 s. The quantity of filler was added to the homogeneous liquid in several portions with decreasing portion size. After each addition, a homogenization took place at 1000 RPM for 60 s in each case. The mixture should become lukewarm but not hot. The final composite paste was achieved after 6-8 additions of filler. A final mixing at 600 RPM for approx. 5 min ensured a bubble-free homogeneous mass.

(47) TABLE-US-00001 TABLE 1 Composition of the composite Ingredient Material A Reference A*) Reference B*) TATATO.sup.1) 10.4 12.9 Product of Ex. 3d.sup.2) 21.5 PETMP.sup.3) 19.0 Bis-GMA 22.4 TEGDMA 9.6 Glass filler G018-053 67.9 67.7 67.8 UF1.5 sil.sup.4) Stabilizer.sup.5) 0.1 0.2 0.1 Photoinitiator.sup.6) 0.1 0.3 0.1 Total 100.0 100.0 100.0 *)comparison example .sup.1)triallyl-1,3,5-triazine-2,4,6-trione .sup.2)Michael addition of tricyclo[5.2.1.0(2.6)]-decanedimethyloldiacrylate (TCD-DA) and 1,3,5-tris(3-mercaptopropyl)-1,3,5-triazine-2,4,6-trione .sup.3)pentaerythritol tetrakis (3-mercaptopropionate) .sup.4)silanized BaAl-borosilicate glass filler with an average particle size of 1.5 m .sup.5)BHT .sup.6)radical-forming blue-light-sensitive photoinitiator: TPO

(48) Starting from the composite pastes, the test pieces were prepared beginning with carefully filling the respective test piece moulds in several portions, wherein air bubbles were prevented by plugging. The test piece moulds are described in the respective standard tests and the specialist literature. For photopolymerization, the samples were exposed to blue light in the wavelength range around 460 nm. In the examples, dental light devices with a light intensity >850 mW/cm.sup.2 (Translux Energy model, from Heraeus Kulzer GmbH) were used in order to irradiate the samples in the exposure range for in each case 20 s. The exposure took place on both sides according to the method descriptions in the specialist literature and in EN ISO 4049:2009 (Dentistry-Polymer-based restorative materials).

(49) Compared with the commercially available cross-linker PETMP with the typical mercaptan odour (reference A) and methacrylate-based dental composites (reference B), the composite material A according to the invention displayed much lower shrinkage stress and polymerization shrinkage. The double bond conversions were comparable to the PETMP composite and higher than in the case of methacrylate-based dental composites.

(50) TABLE-US-00002 TABLE 2 Properties of the composite Material properties Material A Reference A*) Reference B*) Bending strength 110 106 106 [MPa].sup.1) Modulus of elasticity 7.7 7.4 6.3 [GPa].sup.2) Double bond conversion 59 60 48 [%].sup.3) Polymerization 2.1 4.1 3.0 shrinkage [vol.-%].sup.4) Shrinkage stress 4.6 6.8 6.2 [MPa].sup.5) *)comparison example .sup.1)according to EN ISO 4049:2009 after 24 h water storage at 37 C. .sup.2)according to EN ISO 4049:2009 after 24 h water storage at 37 C. .sup.3)measurement by means of FTIR-ATR after 10 min (20 sec exposure, blue light) .sup.4)measurement after 10 min (deflecting disc method according to Watts & Cash) .sup.5)measurement after 24 h (photoelastic method according to Ernst)