Glycylglycine and Its Morpholide Derivatives Containing 5-( p -Tolyl)isoxazole and 4,5-Dichloroisothiazole Moieties

The acylation of glycylglycine and its morpholide with 4,5-dichloroisothiazole-3-carbonyl chloride gave the corresponding N -(4,5-dichloroisothiazole-3-ylcarbonyl) derivatives. N -[5-( p -Tolyl)isoxazole-3-car­bonyl] analogs were synthesized by acylation of glycylglycine and its morpholide with 5-( p -tolyl)isoxazole-3-carbonyl azide since treatment of the same substrates with 5-( p -tolyl)isoxazole-3-carbonyl resulted in the formation of mixtures of products. The reactions of glycylglycine and its morpholide with phenyl N -(4,5-di­chloroisothiazol-3-yl)- and N -[( p -tolyl)isoxazol-3-yl]carbamates afforded derivatives containing an urea fragment. Some of the synthesized compounds showed antitumor activity and enhanced the antitumor effect of doxorubicin.