Investigation the chemical reactivity of positions N-3, C-5 and C-6-methylgroup in Biginelli type compounds and synthesis of new dihydropyrimidine derivatives

The compounds 5-ethoxycarbonyl-1,6-dimethyl-4-(3-nitrophenyl)-3,4-dihydropy rimidin-2(1H)-one (5) and 5-ethoxycarbonyl-1-phenyl-6-methyl-4-(3-nitrophen yl)-3,4-dihydropyrimidin-2(IH)-one (1) were prepared by the Biginelli conde nsation method and they converted to eight N-3 substituted dihydropyrimidin es using NaH and various electrophiles (ClCO2Et, TsCl, AC(2)O, AcCl and PhC OCl). Compound (1) was mono-brominated at the C-6-methyl group using bromin e solution. Reaction of the bromo derivative with amino nucleophiles such a s methyl amine and cyclohexyl amine produced two pyrrolo-pyrimidine derivat ives. All the compounds except 5-ethoxycarbonyl-1-phenyl-6-methyl-4-(3-nitr ophenyl)-3,4-dihydropyrimidin-2(1H)-one (4) were purified by recrystallizat ion methods. The structure of all the new compounds was confirmed using FT- ir, H-1 nmr, C-13 nmr spectral and elemental analyses methods.