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

作者：Ibrahim Hamada Mohamed; Behbehani Haider^*; Makhseed Saad; Elnagdi Mohamed H

来源：Molecules, 2011, 16(5): 3723-3739.

DOI：10.3390/molecules16053723

• cyanoacetic acid
• cyanoacetamides
• triazolo[4,5-b]pyridine
• pyrazolo[4,3-b]pyridine
• p-nitrophenylacetic acid
• zeolite

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.

• 出版日期2011-5