Friedländer condensation of 5‐aminopyrazole‐4‐carbaldehydes with reactive α‐methylene ketones: Synthesis of pyrazolo[3,4‐ b ]pyridines | Zendy

Jachak Madhukar N. | Zendy; Avhale Appasaheb B. | Zendy; Tantak Chanda D. | Zendy; Toche Raghunath B. | Zendy; Reidlinger Claudia | Zendy; Stadlbauer Wolfgang | Zendy

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Friedländer condensation of 5‐aminopyrazole‐4‐carbaldehydes with reactive α‐methylene ketones: Synthesis of pyrazolo[3,4‐ b ]pyridines

Author(s) -

Jachak Madhukar N.,

Avhale Appasaheb B.,

Tantak Chanda D.,

Toche Raghunath B.,

Reidlinger Claudia,

Stadlbauer Wolfgang

Publication year - 2005

Publication title -

journal of heterocyclic chemistry

Language(s) - English

Resource type - Journals

SCImago Journal Rank - 0.321

H-Index - 59

eISSN - 1943-5193

pISSN - 0022-152X

DOI - 10.1002/jhet.5570420710

Subject(s) - chemistry , pyridine , potassium hydroxide , diethyl malonate , methylene , condensation , catalysis , medicinal chemistry , acetone , piperidine , organic chemistry , physics , thermodynamics

A series of 1,3,6‐trisubstituted and 1,3,5,6‐tetrasubstituted pyrazolo[3,4‐ b ]pyridines 5 has been synthesized by Friedlander condensation of 5‐arninopyrazole‐4‐carbaldehydes 3 with α‐methylene ketones such as acetone (4a) or acetophenones 4b‐f with potassium hydroxide as basic catalyst. Condensation of 5‐aminopyrazole‐4‐carbaldehydes 3 and unsymmetric dialkylketones 6 yielded mixtures of isomeric pyra‐zolo[3,4‐ b ]pyridine derivatives 7 and 8 . Condensation of 5‐aminopyrazole‐4‐carbaldehydes 3 with CH‐acidic acylacetonitriles 9 and acylacetates 11 with piperidine as basic catalyst yielded pyrazolo[3,4‐ b ]pyri‐dine‐5‐carbonitriles 10 and pyrazolo[3,4‐ b ]pyridine‐5‐carboxylates 12 ; with diethyl malonate 13 as CH‐acidic component, pyrazolo[3,4‐ b ]pyridin‐6‐ones 14 were obtained.

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