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Part-IExperimentalUV(MeOH): 312 nm12. Synthesis of ethyl 2-amino-5,6,7,8-tetrahydro-4H-cyclohepta[b]thiophene-3-carboxylate (Ixii) (Method B)This compound was prepared in two steps by reacting cycloheptanone (11.2 gm; 0.1mole), ethyl cyanoacetate (11.3 gm; 0.1 mole) and sulfur (2.6 gm; 0.08 mole) as per theprocedure described for compound (Iv). The crystalline product separated was filtered,washed with 50% aq. ethanol and dried. The product, (8.0 gm; 71% yield) of m.p. 88-90 o C (88-90 o C) 6 was characterized as ethyl 2-amino-5,6,7,8-tetrahydro-4H-cyclohepta-[b]thiophene-3-carboxylate (Ixii).Mol. Formula : C 12 H 17 NO 2 S; Mol. Wt. 239.1IR (KBr) cm -1 : 3453, 3337(γ NH ), 3112, 2895(γ C-H ), 1723(γ COOEt ).UV(MeOH) : 310 nm4.2 Synthesis of starting materials (Ixiii-xvii) of other condensed pyrimidines (Ixiiixvii)13. Synthesis of 3-amino-2-carbethoxy-4, 6-dimethylthieno[2,3-b]pyridine (Ixiii)a. Synthesis of thiocyanoacetamideTo a solution of malononitrile (6.6 gm; 1 mole) in ethanol (20 ml); triethylamine (0.5 ml)was added and the mixture was stirred while H 2 S gas was bubbled into the solution for 3-4 hrs at room temperature. Three crops of crystals were isolated and recrystallization fromethanol to yield 7.84 gm (80%) of a crystalline product. m.p. 114-115 o C (116-117 o C) 7 .Mol. Formula : C 3 H 4 N 2 S; Mol. wt. 100b. Synthesis of 4, 6-dimethyl-3-cyano-2-mercaptopyridineTo a suspension of thiocyanoacetamide (9.8 gm; 0.1 mole) in ethanol (100 ml), wasadded acetylacetone (10 gm; 0.1 mole) followed by triethylamine (1 ml) dropwise, whilestirring the solution. Thereafter, the solution was allowed to stand at room temperature for1 hr. The solid separated out was filtered washed with cold ethanol and dried.171