Convenient synthesis of arylazo derivatives of quinoxaline, 1,4‐benzothiazine, and 1,4‐benzoxazine

Abstract

Arylazo derivatives of quinoxaline (1,4‐benzodiazine), 1,4‐benzothiazine, and 1,4‐benzoxazine have been prepared by condensation of hydrazidoyl halides with o‐phenylenediamine, o‐aminothiophenol, and o‐aminophenol, respectively (Table I). This method seems to be more general than the approach using coupling of reactive diazonium salts with, e.g., 277–1,4‐benzothiazine. Both the spectral data and the results of HMO calculations of bonding energies of the azo compounds obtained in this study indicate that they exist predominantly in the hydrazone tautomeric form.

A One-Pot Synthesis of [1,2,4]Triazino[4,3-b]-[1,2,4,5]tetrazines

“…Similar results were obtained when 2 was refluxed with 6 under the same reaction conditions. At first, it was anticipated that such reactions would yield the respective [1,2,4]-triazino [4,3-b] [1,3,4]thiadiazine derivatives by analogy to the reactions of 6 with 2-aminothiophenols, which were reported to give benzothiadiazine derivatives [6]. Surprisingly, however, the products isolated from the reactions of 6a -l with 1 and 2 were free of sulfur.…”

A convenient one‐pot synthesis and antimicrobial activity of pyrimido[1,2‐b][1,2,4,5]tetrazines

“…Refluxing of 1 with 2 in ethanol in the presence of triethylamine until hydrogen sulfide ceased to evolve and working up the reaction mixture gave, in each case, one product as evidenced by tlc analysis. At first, it was anticipated that such reactions would yield the respective pyrimido [4,3-b] [1,3,4]thiadiazine derivatives by analogy to the reactions of 1 with 2-aminothiophenols which were reported to give benzothiadiazine derivatives [7]. Surprisingly, however, the products isolated from the reactions of 1a-i with 2 were found to be free of sulfur.…”

Reactions with Naphthoylhydroxlmoyl Chlorides: Synthesis of Derivatives of Isoxazole, Pyrrolidino[3,4‐d]isoxazoiin‐4,6‐dione, lmidazo[1,2‐a]pyridine, lmidazo[1,2‐a]pyrimidine, Benzotriazine and Benzothiadiazine

“…Compound 24 was readily converted to 3-naphtboyI-1 ,3,4-benzotriazine ZS by oxidation with hydrogen peroxide in acetic acid 13 at 25 "C. Structure 18 was eliminated because no absorption line in the region 1650-1800 em" due to the CO group in the IR spectrum of the reaction product."…”