Synthesis, aromatization and crystal structure of diether 4-(3,4-methylene dioxylphenyl)-2,6-dimethyl-1,4-dihydropyridine-3,5-dicarboxylate under microwave irradiation

Diether 4-(3,4-methylene dioxylphenyl)-2,6-dimethyl- 1,4-dihydropyridine-3,5-dicarboxylate 1 (C20H23NO6) has been synthesized by the reaction of 3,4-methylenedioxylbenzaidehyde, ethyl acetoacetate and ammonium acetate under microwave irradiation without solvent. Diether 4-(3,4-methylene dioxylphenyl)-2,6-di methyl-3,5-dicarboxylate 2 was obtained by the reaction of 1 with NDC under microwave irradiation without solvent. Their structures were determined by single-crystal X-ray diffraction. The crystal of 1 is monoclinic, space group P2(1)/c with a =14.864(3), b =9.830(1), c =14.517(3)Angstrom, beta = 115.25(1)degrees, V =1918.6(6) Angstrom(3), Z=4, M-r =373.3 D-c = 1.293g/cm(3), mu(MoKalpha)=0.096mm(-1), F(000)=792. The structure was solved by direct methods and refined by full-matrix least squares method to the final R=0.0496 and wR=0.1368. The crystal of 2 is triclinic, space group P (1) over bar with a = 8.915(l), b=10.575(l), c=11.904(1)Angstrom, alpha =102.19(l), beta=109.43(l), gamma =108.94(l)degrees, V=934.8(2) Angstrom(3), Z = 2, M-r=371.38, D-c =1.319g/cm(3), mu(MoKalpha) = 0.098mm(-1), F(000) = 392, R = 0.0412 and wR = 0.1011.