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Part-IIExperimental34. Synthesis of ethyl 4-chloro-2-chloromethyl-5-methylthieno[2,3-d]pyrimidine 6-carboxylate (VIiv)A mixture of ethyl 2-chloromethyl-5-methyl-4-oxothieno[2,3-d]pyrimidine 6-carboxylate (Viv, 5.7 gm; 0.02 mole) and phosphorus oxychloride (6.0 gm; 0.04 mole)were reacted under microwave irradiation (6 min) as per procedure described for thecompound VIi. The crude product on recrystallization from hexane that yielded ethyl 4-chloro-2-chloromethyl-5-methylthieno[2,3-d]pyrimidine 6-carboxylate (VIiv).M.P. : 135-137 o C (135-137 o C) 3 ; Yield: 75%Mol. Formula : C 11 H 10 Cl 2 N 2 O 2 S; Mol. Wt. 305.2IR (KBr) cm -1 : 2984(γ C-H ), 1718(γ C=O ), 1534(γ C=C ).1 H NMR (CDCl 3 )δppm : 1.43 (3H, t, CH 2 CH 3 , J = 7.2 & 6.9), 3.06 (3H, s, CH 3 ), 4.42(2H, q, CH 2 CH 3 , J = 6.9 & 7.2), 4.78 (2H, s, CH 2 Cl).MS m/e : 304 (M + ), 289, 276.35. Synthesis of 4-chloro-2-chloromethyl-5,6,7,8-tetrahydro-3H-benzo[4,5]thieno-[2,3-d]pyrimidine (VIv)A mixture of 2-chloromethyl-5,6,7,8-tetrahydro-3H-benzo[4,5]thieno[2,3-d]pyrimidin-4-one (Vvii, 5.0 gm; 0.02 mole) and phosphorus oxychloride (6.0 gm; 0.04 mole) werereacted under microwave irradiation (4 min) as per procedure described for the compoundVIi. The crude product on recrystallization from hexane that yielded 4-chloro-2-chloromethyl-5,6,7,8-tetrahydro-3H-benzo[4,5]thieno[2,3-d]pyrimidine (VIv).M.P. : 80-82 o C (80-82 o C) 3 ; Yield: 70%Mol. Formula : C 11 H 10 Cl 2 N 2 S; Mol. Wt. 273.2IR (KBr) cm -1 : 2941(γ C-H ), 1447(γ C=C ), 736(γ C-Cl )1 H NMR (CDCl 3 )δppm : 1.99 (4H, s, CH 2 at 6 & 7), 2.57 (3H, s, CH 3 ), 2.95 (3H, s, CH 3at 5), 3.12 (3H, s, CH 3 at 8), 4.80 (2H, s, CH 2 Cl).MS m/e : 275(M + ), 244, 237, 209.377