SYNTHESIS OF ACYL DERIVATIVES N-SUBSTITUTED AROMATIC CARBAMATES AND THEIR SOME TRANSFORMATIONS
By acylation of N-methyl 3 (4)[(methoxycarbonyl)amino] phenylcarbamates with acetic anhydride in the presence of Mg(ClO4)2 1 mol % for 1 h heating at 70 °C obtained N-methyl 2-acetyl-5 (4)-[(methoxycarbonyl) amino]phenylcarbamates in high yield. Acylation under similar conditions corresponding ortho-isomer occurs regioselectively and leads to the formation of 4-acyl substituted dicarbamate. Acylation of methyl N-(4-hydroxyphenyl)carbamate with acetic anhydride in the presence of magnesium perchlorate, and concentrated sulfuric acid occurs as O-acylation. By heating of 4-[(methoxycarbonyl)amino]phenylacetate for 3 hours in dichloroethane in the presence of anhydrous aluminum chloride was obtained methyl N-(3-acetyl-4-hydroxyphenyl) carbamate which upon condensation with veratric aldehyde under basic catalysis formed methyl N-{3-[(E)-3-(3,4-dimethoxyphenyl)-2-propenoyl]-4-hydroxyphenyl}carbamate, which when heated in DMSO in the presence of I2 converted to the corresponding chromone. The structure of the novel compounds was confirmed by IR, 1H NMR spectroscopy and mass spectrometry.