Synthesis of N-aryl- and N,N-diethyl-9-methyl-11-sulfanylidene-8-oxa-10,12-diazatricyclo[7.3.1.02,7]trideca-2,4,6-triene-13-carboxamides

Three-component condensation of N-aryl- and N,N-diethyl-3-oxobutanamides with salicylaldehyde and thiourea in ethanol in the presence of sodium hydrogen sulfate afforded N-aryl- and N,N-diethyl-9-methyl-11-sulfanylidene-8-oxa-10,12-diazatricyclo[7.3.1.0^2,7]trideca-2,4,6-triene-13-carboxamides. Reaction of the same compounds in the absence of a catalyst under solvent-free conditions gave N-aryl-6-(2-hydroxyphenyl)-4-methyl-2-sulfanylidene-1,2,3,6-tetrahydropyrimidine-5-carboxamides.