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Part-IIResults and Discussion4.1 Synthesis of Starting Materials:4.1.1 Synthesis of o-aminothiophenes (The Gewald reaction)4.1.2 Synthesis of other o-amino esters substrate4.1.1 Synthesis of o-Aminothiophenes (The Gewald reaction)The starting material used for the synthesis of 2-substituted condensed pyrimidines wassynthesized using classical Gewald reaction, which is explained in Part-1 of this thesis.Table-36: Physical data of 2-amino-3-carbethoxythiophenes (Ii-xii)OR 1OR 2 NH 2SSr. No R 1 R 2 Mol.For.Sol. of recrystIi -(CH 2 ) 4 - C 11 H 15 NO 2 S(E)Iii -CH 3 -COOCH 3 C 10 H 13 NO 4 S(E)Iiii -CH 3 -COOC 2 H 5 C 11 H 15 NO 4 S(B)Iiv -CH 3 -CH 3 C 9 H 13 NO 2 S(E)Iv -C 6 H 5 H C 13 H 13 NO 2 S(E)Ivi 4-CH 3 OC 6 H 4 H C 14 H 15 NO 3 S(E)Ivii 4-CH 3 C 6 H 4 H C 14 H 15 NO 2 S(E)Iviii 4-BrC 6 H 4 H C 13 H 12 BrNO 2 S(E)Iix 4-ClC 6 H 4 H C 13 H 12 ClNO 2 S(E)Ixi -(CH 2 ) 5 - C 12 H 17 NO 2 S(E)Ixii -(CH 2 ) 2-N-(CH 2 C 6 H 5 )CH 2 - C 17 H 16 ClN 3 OS(E-C)E =Ethanol, B = BenzeneYield M.P. Time Route(%)o C (hrs.)80 110-112 3 A70 80-82 2-3 A50 103-105 2 A50 92-93 3 A75 95-97 15-18 B73 96-99 15-18 B89 102-104 15-18 B76 78-80 15-18 B80 102-104 15-18 B71 75-77 15-18 B78 232-234 15-18 B321