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4.2 Synthesis of condensed 2-substitutedpyrimidinesPart-IIResults and DiscussionFor the first time a rapid, microwave assisted green chemical synthesis of condensed 2-substitutedpyrimidin-4(3H)-ones involving the condensation of a variety of nitriles witho-aminoesters of thiophene, benzene, dimethoxybenzene, pyridothiophene, 4-methoxybenzothiopheneand quinazolinone in the presence of catalytic amount of HCl alone orwith the Lewis acid, AlCl 3 under solvent free conditions is reported, herein (Scheme 1).OOONVxxv-xxxNHCH 3 CN OC 2 H 5aNH 2Ic ClCH 2 CNbNNNHVxviii-xxivClONHNVi-xviiwhere,R 1=R 2ClMeO, , ,SN N,NMeOS,SOOCH 3R 1 , R 2 = -(CH 2 ) 4 -; R 1 , R 2 = CH 3 ; R 1 = 4-CH 3 -C 6 H 4 , R 2 = H;R 1 = CH 3 , R 2 = COOC 2 H 5 ; R 1 = C 6 H 5 , R 2 = H.Scheme 1: Reaction conditions a: Under microwave irradiation; 350W, 20-75 min (60-94%), b: Under microwave irradiation; 350W, 20-50 min (83-99%), c: Undermicrowave irradiation; 350W, 10-40 min (66-95%).These reactions under microwave irradiation at 350W were accomplished by usingcatalytic amount of concentrated HCl (33%w/v) in very short time periods. The reactiontime varied depending upon the type of the nitrile used. The reactions with acetonitrilewere completed in 40-75 min to obtain the condensed 2-methylpyrimidin-4(3H)-ones(Vxxv-xxx) with isolated yields ranging from 68-94%. The reactions with acrylonitrilewere completed in 20-50 min time and afforded the condensed 2-chloroethylpyrimidin-323