Synthesis of a novel fused tricyclic heterocycle, pyrimido[5,4-e][1,4]thiazepine, and its derivatives

Abstract

Sequential treatment of 5-bromo-2,4-dichloro-6-(chloromethyl)pyrimidine with 2-aminothiophenol and secondary amines afforded a series of 2-[(5-bromo-2-chloro-6-aminopyrimidin-4-yl)methylthio]aniline derivatives. Reaction of the latter compounds with secondary amines in ethanol gave a family of new 5,7-diamino-5,11-dihydropyrimido[5,4-e][1,4]benzothiazepines.

Pure Water-Induced Dehalogenation of 2,4-Di-tert-amino-6-substituted-5-halogenopyrimidines

“…As illustrated in Scheme , 5-bromo-2,4-dichloro-6-(chloromethyl)­pyrimidine ( 4 ) which was synthesized by an established method, was reacted with 4-amino-5-methyl-4 H -1,2,4-triazole-3-thiol ( 5 ) at −20 °C to give the substituted product 6 . Reaction of 6 with various secondary amines afforded compounds 7a – e .…”

An Efficient Route to Pyridazino[4, 3‐e][1, 3, 4]thiadiazines

“…Prompted by these findings and in continuing our synthetic studies on bioactive heterocycles and fused [1,3,4]thiadiazines we now exhibit a general and convenient procedure for the synthesis of a host of pyridazino[4,3‐ e ][1,3,4] thiadiazines in a single step via heterocyclization of 4‐bromo‐3,6‐dichloropyridazine with alkyl‐2‐phenylhydrazinecarbodithioates in the presence of triethylamine in boiling acetonitrile.…”

An Alternative Approach to the Synthesis of New Pyrimido[5′,4′:5,6][1,4] Thiazino[2,3-B]Quinoxaline Derivatives

“…15 It is well known that pyrimidine and fused pyrimidines are of great biological interest, especially as antiviral, antitumor and antimicrobial agents. 16 As a continuation of our work on the synthesis of biologically active heterocyclic compounds, [17][18][19] we became interested in the synthesis of pyrimido[5′,4′:5,6] [1,4] thiazino [2,3-b]quinoxalines. A literature survey revealed that there is only one reference dealing with the synthesis of this heterocyclic system, employing 4,5-diaminopyrimidine-6(1H)thione and 2,3-dichloroquinoxalines as the starting materials.…”