Synthesis of quinazoline derivatives containing veratrole and benzo-15-crown-5 moieties

Abstract

The condensation of (benzo-15-crown-5

Anomalous behavior of the amides of benzo-and dibenzocrown thiocarboxylic acids under the conditions of methylation

“…Such fragmentation is typical of crown ethers, and we have observed it before in other derivatives [6,7]. In the 1 H NMR spectrum of the nitriles there are signals for the protons of the benzene ring in the form of a doublet, a singlet, and a doublet in the region of 6.8-7.2 ppm, characteristic of 1',2',4'-trisubstituted benzene, and a multiplet for the macrocycle in the region of 3.7-4.2 ppm.…”

Thioamides as Useful Synthons in the Synthesis of Heterocycles

“…Analogous condensation−cyclization reactions of primary aromatic thioamides with anthranilic acid were reported by Walther and Pawlewski a century ago. Recently, the same reaction path was used to obtain several new derivatives of quinazolin-4-(3 H )-one 197 . − All of these reactions require high-temperature conditions (135−140 °C) (Figure ).

6

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“…Recently, the same reaction path was used to obtain several new derivatives of quinazolin-4-(3H)-one 197. [121][122][123] All of these reactions require high-temperature conditions (135-140 °C) (Figure 6). 124 The crucial step here is the intramolecular cyclization, which proceeds through a nucleophilic attack of the amine group on the S-alkylated thiocarbonyl function.…”