INTERACTION OF 1,3λ⁴δ</sup>2</sup>,2,4-BENZODITHIADIAZINES WITH NEUTRAL AND CHARGED S-ELECTROPHILES: SCl₂, C₆F₅SCl, AND NS2⁺

Abstract

Reactions of 1,3λ⁴δ²,2,4-benzothiadiazines with SCl₂, C₆F₅SCl, and [NS₂][SbF₆] leading to 1,2,3-benzodithiazolium salts (Herz salts) were investigated. The relative rate of reaction with SCl₂ significantly depends on the nature of the substituent and its position in the carbocycle. Halogen substituents Cl, Br, and I slow down the reaction, especially if located closely to the heterocycle (positions 5 and 8). In the case of C₆F₅SCl and R = H, chlorination of the carbocycle and opening of the heterocycle also takes place with the formation of 7chloro-1,3λ⁴δ²,2,4-benzothiadiazine аnd C₆F₅–S–N=S=N–Ar (Ar = 2-Cl-6-F₅C₆SC₆H₃), respectively. In the reaction with NS₂⁺, along with contraction of the heterocycle, also its expansion occurs with the formation of 1,2,4λ⁴δ²,3,5-benzotrithiadiazepine.

Authors: Alexander Yu. Makarov*, Irina Yu. Bagryanskaya, Vladimir V. Zhivonitko