title: Acylation of heteroaromatic amines: facile and efficient synthesis of a new class of 1,2,3-triazolo[4,5-b]pyridine and pyrazolo[4,3-b]pyridine derivatives.
abstract: 1,2,3-Triazolo[4,5-b]pyridines and pyrazolo[4,3-b]pyridines can be readily prepared via cyanoacetylation reactions of 5-amino-1,2,3-triazoles 1a,b and 4-amino- pyrazole 2 followed by subsequent cyclization of the formed cyanoacetamides. Reactions of amines 1a,b with a mixture of p-nitrophenylacetic acid and acetic anhydride under microwave irradiation conditions afforded the corresponding amides 15a,b that underwent cyclization to form 1,2,3-triazolo[4,5-b]pyridines 16a,b upon heating in DMF solutions containing sodium acetate. Reactions of 1a,b with active methylene compounds, including 17a-c, in the presence of zeolites as catalyst also afforded 1,2,3-triazolo[4,5-b]pyridine derivatives 20a-f via the intermediacy of triazole derivatives 19 and not 18.
authors.affiliation: Chemistry Department, Faculty of Science, Kuwait University, P.O. Box 5969, Safat 13060, Kuwait. hbehbehani@live.com
authors.forename: Hamada Mohamed
authors.initials: HM
authors.lastname: Ibrahim
authors.forename: Haider
authors.initials: H
authors.lastname: Behbehani
authors.forename: Saad
authors.initials: S
authors.lastname: Makhseed
authors.forename: Mohamed H
authors.initials: MH
authors.lastname: Elnagdi
mesh_terms: D000085:Acetates / Q000737:chemistry*; D000215:Acylation; D000588:Amines / Q000737:chemistry*; D015394:Molecular Structure; D009570:Nitriles / Q000737:chemistry*; D009596:Nitrophenols / Q000737:chemistry; D011725:Pyridines / Q000138:chemical synthesis* / Q000737:chemistry*; D014230:Triazoles / Q000737:chemistry*; D017641:Zeolites / Q000737:chemistry
chemical_list: D000085:Acetates; D000588:Amines; D009570:Nitriles; D009596:Nitrophenols; D011725:Pyridines; D014230:Triazoles; D017641:Zeolites; C008642:4-nitrophenyl acetate; C007170:cyanoacetic acid; C031594:2-cyanoacetamide