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Part-IExperimental4. Reaction of 2-amino-3-carbethoxy-4,5-dimethylthiophene with chloroacetonitrilein the presence of dry hydrogen chloride gas (IIiv)A stream of dry hydrogen chloride gas was bubbled through an ice-cold mixture of 2-amino-3-carbethoxy-4,5-dimethylthiophene (Iiv, 11.9 gm; 0.06 mole) and chloroacetonitrile(6.8 gm; 0.09 mole) in dry dioxane (60 ml) for 6-8 hrs. The reaction mixture wasworked up as for IIi. The crude product on recrystallisation from dioxane yielded fineneedles (15 gm; 83%), m.p 252-254 o C (253-255 o C) 3 , characterized as 2-(chloromethyl)-5,6-dimethylthieno[2,3-d]pyrimidin-4(3H)-one (IIiv).Mol. Formula : C 9 H 9 ClN 2 OS; Mol. Wt. 228.7IR(KBr)/cm -1 : 2917(γ C-H ), 1662(γ CONH ), 1211(γ CH2 ), 769(γ C-Cl ).NMR (CDCl 3 )δppm : 2.39 (3H, s, CH 3 ), 2.47 (3H, s, CH 3 ), 4.51 (2H, s, CH 2 ), 10.03(1H, s, br, NH).MS m/e : 229(M + ).5. Reaction of ethyl 2-amino-4-phenylthiophene 3-carboxylate with chloroacetonitrilein the presence of dry hydrogen chloride gas (IIv)A stream of dry hydrogen chloride gas was bubbled through an ice-cold mixture of ethyl2-amino-4-phenylthiophene 3-carboxylate (Iv, 14.8 gm; 0.06 mole) and chloroacetonitrile(6.8 gm; 0.09 mole) in dry dioxane (60 ml) for 6-8 hrs. The reaction mixture was workedup as for IIi. The solid separated was filtered, washed with water and dried. The crudeproduct on recrystallisation from dioxane yielded fine needles (18 gm; 80%), m.p 220-222 o C (221-223 o C) 3 , characterized as 2-(chloromethyl)-5-phenylthieno[2,3-d]pyrimidin-4(3H)-one (IIv).Mol. Formula : C 13 H 9 ClN 2 OS; Mol. Wt. 276.7IR (KBr) cm -1 : 2855(γ C-H ), 1663(γ CONH ), 1294(γ CH2 ), 1046 and 748(γ C-Cl ).NMR (CDCl 3 )δppm : 4.58 (2H, s, CH 2 ), 7.31-7.52 (5H, m, Ar-H and 1H at 6 position),12.69 (1H, s, br, NH).MS m/e : 276(M + ).179