Synthesis of substituted thiobenzoxazoles/benzothiazoles: inhibition of cellular respiratory and monoamine oxidase activities and anticonvulsant property.

Several 2-(substituted alkoxy/hydrazinocarbonyl acetanilidothio)benzoxazoles/benzothiazoles were synthesized and characterized by their sharp melting points, elemental analyses, and IR spectra. All thiobenzoxazoles/benzothiazoles possessed low anticonvulsant activity, which was reflected by the 10-40% protection afforded by these compounds against pentylenetetrazol-induced convulsions. All thiobenzoxazoles/benzothiazoles inhibited selectively the nicotinamide adenine dinucleotide (NAD)-dependent oxidation of pyruvate, DL-isocitrate, and alpha-ketoglutarate by rat brain homogenates. NAD-independent oxidation of succinate remained unaltered. All 2-(substituted hydrazinocarbonyl acetanilidothio)benzoxazoles/benzothiazoles inhibited monoamine oxidase activity of rat brain homogenates. Greater monoamine oxidase inhibition was observed with thiobenzothiazoles than with the corresponding thiobenzoxazoles/benzothiazoles was found to be unrelated with their ability to inhibit cellular respiratory and monoamine oxidase activities of rat brain homogenates.