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5. Synthesis of ethyl 2-amino-4-phenylthiophene-3-carboxylate (Iv) (Method B)Step-IPart-IExperimentalAcetophenone (12.0 gm; 0.1 mole), ethyl cyanoacetate (11.3 gm; 0.1 mole), glacial aceticacid (4.8 gm; 0.08 mole), anhydrous ammonium acetate (1.54 gm; 0.02 mole) and drybenzene (50 ml) were refluxed in a round bottomed flask, fitted with a Dean-Starkcondenser until the total water removed in the side arm was slightly excess than thecalculated value. Benzene was distilled out thereafter and reaction mixture was dissolvedin dichloromethane (50 ml) and given washings of aq. NaHCO 3 (20 ml; 10% w/vsolution), aq. NaCl (20 ml; 10% w/v solution) and water (20 ml). The organic layer wasseparated, dried (Na 2 SO 4 ) and dichloromethane was distilled out. The solid productalkylidene ethyl cyanoacetate obtained (24.2 gm) was used as such for the second step,without purification.Step-IIThe alkylidene ethyl cyanoacetate was thereafter dissolved in methanol (50 ml) and sulfur(2.6 gm; 0.08 mole) was added, the reaction mixture was then stirred and maintained at50-60 o C. Then, diethylamine (7.39 gm; 0.1 mole) was added dropwise over 30 min. at atemperature around 60 o C. The reaction mixture was stirred further at 50 o C for 6-8 hrs &cooled overnight. The crystalline product separated was filtered, washed with 50% aq.ethanol and dried. The product, (9.0 gm; 75% yield) melting at 95-97 o C, (97-99 o C) 5 , wascharacterized as ethyl 2-amino-4-phenylthiophene-3-carboxylate (Iv).Mol. Formula : C 13 H 13 NO 2 S; Mol. Wt. 247.3IR (KBr) cm -1 : 3435, 3320(γ NH ), 3163, 2980(γ C-H ), 1722(γ COOEt ).UV(MeOH) : 298.4 nm6. Synthesis of ethyl 2-amino-4-(4-methoxyphenyl)thiophene-3-carboxylate (Ivi)(Method B)This compound was prepared in two steps by reacting 4-methoxyacetophenone (15.0 gm;0.1 mole), ethyl cyanoacetate (11.3 gm; 0.1 mole) and sulfur (2.6 gm; 0.08 mole) asdescribed for compound (Iv). The crystalline product separated was filtered, washed with50% aq. ethanol and dried. The product, (11 gm; 73.3% yield) melting at 205-208 o C,(208-210 o C) 5 was characterized as ethyl 2-amino-4-(4-methoxyphenyl)thiophene-3-carboxylate (Ivi).168