ISSN:
1434-193X
Keywords:
Heteroarenes
;
Carbanions
;
Pyran-2-ones
;
Regioselectivity
;
Ring transformation reaction
;
Chemistry
;
General Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Pyrazolo[1,5-a]pyridines (3) and pyrano[4,3-d]pyrazolo[1,5-a]pyridines (4) have been synthesized from the reaction of pyran-2-one (1) and 5-aryl-3-cyanomethyl-1H-pyrazole (2) through carbanion-induced ring transformation reactions. A regioselective synthesis of highly functionalized polysubstituted pyrazolo[1,5-a]pyridines (6, 7) has also been achieved from the reaction of 2 with polarised ketene dithioacetals (5) and arylidenemalononitrile, respectively. An analogous reaction of 1 with 2-cyanomethyl-1H-benzimidazole (8) has also afforded the fused heterocycles 9 and 10. The cyano function in 9 has been exploited for acid-catalysed cyclization with thiosemicarbazide to obtain 11 in high yield.
Type of Medium:
Electronic Resource
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