Synthesis and reactivity of cyanomethyl 2-amino-4-methylthiazolyl ketone. A facile synthesis of novel pyrazolo[5,1-c]1,2,4-triazine, 1,2,4-triazolo[5,1-c]1,2,4-triazine, 1,2,4-triazino[4,3-a]benzimidazole, pyridazine-6-imine and 6-oxopyridazinone derivatives

✍ Scribed by Samia M. Sayed; Mohamed A. Raslan; Mohamed A. Khalil; Kamal M. Dawood

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 168 KB
• Volume: 10
• Category: Article
• ISSN: 1042-7163
• DOI: 10.1002/(sici)1098-1071(1999)10:5<385::aid-hc8>3.0.co;2-o

✦ Synopsis

The novel and versatile cyanomethyl 2amino-4-methylthiazolyl ketone (5) was prepared by treatment of bromomethyl 2-amino-4-methyl thiazolyl ketone (4) with potassium cyanide. Reaction of 5 with heterocyclic diazonium salts 6a,b and 10 afforded the corresponding hydrazones 7a,b and 11, respectively. Refluxing of the hydrazones in pyridine afforded the corresponding pyrazolo [5,1- 2,4-triazine, and 1,2,4-triazolo[4,3a]benzimidazole derivatives 8a,b and 12, respectively, via intramolecular cyclization. Compound 5 coupled also with benzenediazonium chloride to afford the corresponding hydrazone 14, which is an excellent precursor for the synthesis of pyridazine-6-imine 17a and pyridazinone 17b. The pyridazine derivatives 17a,b were also prepared by an independent route, that is, the condensation with malononitriles and coupling with benzenediazonium chloride, followed by intramolecular cyclization.