Synthesis of Triphenodithiazines and Triphenodiselenazine Having Ester Groups

Abstract

Starting from diethyl 2, 6-dioxo-1, 4-cyclohexanedicarboxylate [1] three routes to diethyl triphenodithiazine-6, 13-dicarboxylates [4] were examined, and it was found that the following route was the best. The reaction of 2-aminobenzenethiolates [2] with diethyl 3, 6dibromo-1, 4-benzoquinone-2, 5-dicarboxylate [5] which was prepared from [1] gave directly four derivatives of [4] in 35-, 55% yields.[4 a-d] were green needles showing the absorption maxima in the visible region of 560-586 nm. The introduction of ester groups at 6 and 13 positions to triphenodithiazine resulted in a lower melting point and higher solubility in organic solvents as compared with triphenodithiazine.
Reduction of diethyl triphenodith iazine-6, 13-dicarboxylate [4a] with phenylhydrazine afforded diethyl 7, 14-dihydrotriphenodithiazine-6, 13-dicarboxylate[8].
Furthermore, diethyl triphenodiselenazine-6, 13- dicarboxylate [11] was synthesized by the reaction of zinc 2-aminobenzeneselenolate [9] with [5] and its reaction mechanism was discussed.