The (1H-Tetrazol-1-yl)arenediazonium Salts as Convenient Reagents for Quinones Arylation: Synthesis of 1,3-Benzoxathiol-2-ones and Naphtho[2,1-d][1,3]oxathiol-2-ones Bearing (1H-Tetrazol-1-yl)phenyl Motif

Abstract

A convenient two-step method for the synthesis of novel 1,3-benzoxathiol-2-ones and naphtho[2,1-d][1,3]oxathiol-2-ones bearing (1H-tetrazol-1-yl)phenyl motif was developed. As a key step of the synthesis, an arylation of quinones (1,4-benzoquinone, 1,4-naphtho-quinones) with the (1H-tetrazol-1-yl)arenediazonium salts was studied and efficient protocols were elaborated to obtain a variety of substituted ((1H-tetrazol-1-yl)phenyl) benzo/naphtho-1,4-quinones in good to excellent yields. An alternative synthesis of ((1H-tetrazol-1-yl)phenyl) naphtho-1,4-quinones via Diels-Alder reaction of tetrazolylphenyl-1,4-benzoquinones was demonstrated. The prepared benzo/naphtho-1,4-quinones readily react with thiourea at room temperature in the presence of a strong mineral acid to form intermediate isothiuronium salts, which cyclize with high yields to condense 1,3-oxathiol-2-ones under heating.