Gema Mikulskiene

Synthesis and Cyclizations of N-(2,3-, 3,4- and 3,5-Dimethylphenyl)-β-alanines

A series of 1-aryl substituted dihydro-, 5-methyldihydro- and 6-methyl-dihydro-2,4(1H,3H)pyrimidinediones and their 2-thio analogues were obtained by reaction of the corresponding β-alanines or α-methyl- and β-methyl-β-alanines with urea or potassium thiocyanate. The reaction of N-(2,3- and 3,5-dimethylphenyl)-α-methyl-β-alanines with ethyl acetoacetate gave 1-(2,3- or 3,5-dimethylphenyl)-2,5-dimethyl-1,4,5,6-tetrahydro-4(1H)pyridones. The combined spectral data obtained by 1H-, 13C-, 1H/13C (HETCOR) NMR and IR provided useful information about the structure of the products synthesized in this work.

Reactions of 9-Alkyl-3-aminocarbazoles with Ethyl-3-oxo-butanoate and Identification of the Products Obtained

The reactions in benzene of 9-alkyl-3-aminocarbazoles with ethyl-3-oxobutanoate yielded ethyl-3-[(9-alkyl-9H-carbazol-3-yl)amino]but-2-enoate condensation products or N-(9-ethyl-9H-carbazol-3-yl)-3-oxobutanamide acylation products. The condensation products were cyclized to the corresponding 4,7-dihydro-pyrido[2,3-c]-carbazol-1-ones upon heating in mineral oil at 240-250 degrees C. The structures of the synthesized compounds were investigated by IR, mass spectrometry, (1)H- and (13)C-NMR spectroscopy and MM2 molecular mechanics and AM1 semi-empirical quantum mechanical methods.