Efficient Synthesis and Biological Properties of New Benzopentathiepins

Abstract

New 6,7-dimethoxybenzopentathiepin and 6-(2-aminoethyl)benzopentathiepin, which are partial structures of varacin, were synthesized from 1.2-dimethoxybenzene and 1,2-benzenedithiol respectively.Recently, the characteristic chemical properties of cyclic polysultides have amacted wide attention in the field of organosulfur chemistry.'We have also reported new methods for the synthesis of benzopentathiepins2 and the related compound^.^Furthermore, we have found many reactions for providing some heterocycles from such cyclic p ~l ~s u l f i d e s .~On the basis of these findings, our interests were directed to the synthesis of new biologically active benzopentathiepin, for example, varacin and lissoclin~toxins,~ which were found in marine natural products and the total syntheses have been recently reported.6In this paper, we wish to report an efficient synthesis and the biological properties of two novel benzopentathiepins, 6,7-dimethoxybenzopentathiepin (A) and 6-(2-aminoethyl)benzopentathiepin (B), which are partial structures of varacin, using our original method with elemental sulfur and gaseous ammonia.2