Self-Neutralizing Carbonic Acidic Catalyzed Synthesis of Benzothiazole Derivatives from Disulfides and Aldehydes in Water

摘要

abstract_textpAn environmental friendly method was developed for preparing benzothiazole derivatives via the reaction of ortho-anilino disulfides with aldehydes promoted by Na2S.9H(2)O in a reversible CO2-H2O system without any other acid additive or organic solvent. Thus, this reaction system greatly simplifies post-processing and allows for disposal without waste. The highly selective protocol affords the corresponding benzothiazoles from the reaction of disulfides and aldehydes with electron-donating or withdrawing groups in good yields. More-over, the dynamic equilibrium relationship between Na2S and the CO2 pressure had been explored by (CNMR)-C-13 in highpressure NMR tube, which firstly demonstrated the carbonic acid was converted into CO32-or HCO3-promoted by Na2S in low or high CO2 pressure. Furthermore, the mechanism of Schiff base formation catalyzed by acid was confirmed by 1HNMR, and the process of benzothiazole formation from disulfide mediated by Na2S in CO2-H2O system was also proposed./p/abstract_text