학술논문
Cycloadducts of phenylethynyl trifluoromethyl sulfone with diphenyldiazomethane and 9-diazofluorene and their transformations under conditions of van Alphen-Hüttel rearrangement.
Document Type
Article
Author
Source
Subject
*SULFONES synthesis
*RING formation (Chemistry)
*BENZENE
*METHANOL
*PYRAZOLES
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Language
ISSN
1070-4280
Abstract
Diphenyldiazomethane and 9-diazofluorene react with phenylethynyl trifluoromethyl sulfone in diethyl ether at 20°C to give 1,3-dipolar cycloaddition products according to the von Auwers rule, the corresponding 3 H-pyrazoles. The adduct with diphenyldiazomethane undergoes thermal van Alphen-Hüttel rearrangement to 4,4,5-triphenyl-3-(trifluoromethanesulfonyl)-4 H-pyrazole on heating in boiling benzene. Under analogous conditions, the adduct with 9-diazofluorene is converted into 3′-phenylspiro[fluorene-9,4′-pyrazol]-5′(1′ H)-one, whereas 3a-phenyl-2,3a-dihydro-3 H-dibenzo[ e, g]indazol-3-one is formed in boiling methanol. The structure of 3′-phenylspiro[fluorene-9,4′-pyrazol]-5′(1′ H)-one was determined by X-ray analysis. [ABSTRACT FROM AUTHOR]