(5,7-Dimethyl-4,6-dioxo-4,5,6,7-tetrahydro[1,2]thiazolo[3,4-(/]pyrimidin-3- yl)acetic acid

(5,7-Dimethyl-4,6-dioxo-4,5,6,7-tetrahydro[1,2]thiazolo[3,4-(i]pyrimidin-3-yl)acetic acid

Step 1 : Methyl 6-amino-l,3-dimethyl-2,4-dioxo-1,2,3,4-tetrahydropyrimidine-5- carbodithioate: 
¹H NMR (300 MHz, CF₃COOD) δ 2.73 (s, 3H), 3.51 (s, 3H), 3.62 (s, 3H).

Step 2: 5,7-Dimethyl-3-(methylsulfanyl)[1,2]thiazolo[3,4-ύT|pyrimidine-4,6(5H,7H)- dione: 

¹H NMR (300 MHz, DMSO-^₆) δ 2.67 (s, 3H), 3.18 (s, 3H), 3.40 (s, 3H). 

Step 3: 5,7-Dimethyl-3-(methylsulfonyl)[1,2]thiazolo[3,4-(/]pyrimidine-4,6(5H,7H)- dione:  

 ¹H NMR (300 MHz, DMSO-(Z₆) δ 3.26 (s, 3H), 3.49 (s, 3H), 3.71 (s, 3H).

Step 4: Diethyl (5,7-dimethyl-4,6-dioxo-4,5,6,7-tetrahydro[1,2]thiazolo[3,4-d]pyrimidin- 3-yl)propanedioate:  ¹H NMR (300 MHz, DMSO-(Z₆) δ 1.32 (t, J = 7.2 Hz, 6H), 3.40 (s, 3H), 3.64 (s, 3H), 4.24-4.37 (m, 4H), 6.05 (s, 1H).

Step 5: Ethyl (5,7-dimethyl-4,6-dioxo-4,5,6,7-tetrahydro[1,2]thiazolo[3,4-d]pyrimidin-3- yl)acetate:; ¹H NMR (300 MHz, DMSCM₆) δ 1.34 (t, J = 6.9 Hz, 3H), 3.40 (s, 3H), 3.63 (s, 3H), 4.30 (q, J= 6.9 Hz, 2H), 4.50 (s, 2H)

Step 6: (5,7-Dimethyl-4,6-dioxo-4,5,6,7-tetrahydro[1,2]thiazolo[3,4-(/]pyrimidin-3- yl)acetic acid: The title compound was prepared according to same procedure as described for Intermediate 1, Step 5 by using above Step 5 intermediate (9.0 g, 31.8 mmol), 6 N H₂SO₄ (80 ml) and dioxane (80 ml) to give 5.8 g of the product as yellow solid; 

 ¹H NMR (300 MHz, DMSO-^₆)
δ 3.22 (s, 3H),
3.46 (s, 3H),
4.51 (s, 2H),
13.45 (br s, 1H).  -0H

Interpretation

 

http://www.google.com/patents/EP2411397A1?cl=en 

(5,7-Dimethyl-4,6-dioxo-4,5,6,7-tetrahydro[1,2]thiazolo[5,4-(i]pyrimidin-3-yl)acetic acid

 

¹H NMR (300 MHz, DMSO-<4) δ 3.22 (s, 3H), 3.46 (s, 3H), 3.96 (s, 2H), 12.57 (br s, 1H).

2-(5,7-Dimethyl-4,6-dioxo-4,5,6,7-tetrahydro[1,2]thiazolo[3,4-ύT|pyrimidin-3-yl)-N-{4- [3 -fluoro-4-(trifluoromethyl)phenyl] - 1 ,3 -thiazol-2-yl } acetamide

 ¹H ΝMR (300 MHz, DMSO-^₆) δ 3.23 (s, 3H), 3.48 (s, 3H), 4.83 (s, 2H), 7.86-8.07 (m, 4H), 12.96 (br s, 1H); APCI-MS (m/z) 500.06 (M+H)⁺.

2-(5,7-Dimethyl-4,6-dioxo-4,5,6,7-tetrahydro[1,2]thiazolo[3,4-ύT|pyrimidin-3-yl)-N-{4- [3 -(trifluoromethy l)pheny 1] -1,3 -thiazol-2 -y 1 } acetamide

 ¹H NMR (300 MHz, DMSO-^₆) δ 3.23 (s, 3H), 3.48 (s, 3H), 4.82 (s, 2H), 7.67- 7.72 (m, 2H), 7.96 (s, 1H), 8.20-8.26 (m, 2H), 12.93 (br s, 1H); APCI-MS (m/z) 482.07 (M+H)⁺.

Ethyl (5,7-dimethyl-4,6-dioxo-4,5,6,7-tetrahydro[1,2]thiazolo[5,4-ύT|pyrimidin-3- yl)acetate

 ¹H NMR (300 MHz, CDCl₃) 
δ 1.28 (t, J= 7.2 Hz, 3H), -CH2CH3
3.39 (s, 3H), 
3.56 (s, 3H), 
4.12 (s, 2H), -CH2CH3
4.21 (q, J= 6.9 Hz, 2H).