Intramolecular 1,5-cyclization of ylides : Synthesis of pyrazolo-[1,5-a]pyridines and indolizines
β Scribed by Y. Tamura; N. Tsujimoto; Y. Sumida; M. Ikeda
- Book ID
- 103393688
- Publisher
- Elsevier Science
- Year
- 1972
- Tongue
- French
- Weight
- 473 KB
- Volume
- 28
- Category
- Article
- ISSN
- 0040-4020
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π SIMILAR VOLUMES
A few syntheses of indolizinea by intramolecular l,5-cyclization have been reported1'2q3\*4q5 . Dihydroindolizine intermediates were not obtained due to rapid oxidation to indolizinea, except in special CEEWJ~ 3,4 . l,&Cycloaddition
## Abstract While 3(5)βaminopyrazole reacts with enaminonitrile to yield pyrazolo[1,5β__a__]pyrimidines, 3βaminoβ5βpyrazolone reacts with the same reagents to yields pyrazolo[3,4β__b__]pyridines.
## Abstract The pyridinium salts **2a,b** reacted with dimethyl acetylenedicarboxylate (DMAD) to give the indolizine derivatives **6a,b**. Pyridinium salts **2a,b** also reacted with pyrazoleβ5βdiazonium salt to afford the hydrazonoyl bromides **8a,b**, which on treatment with aqueous ethanolic sod