Bibliographic Details
| Title: |
Synthesis of 3,3-diphenyl-3 H-pyrazoles applying vinyl sulfones as chemical equivalents of acetylenes in reaction of 1,3-dipolar cycloaddition to diphenyldiazomethane. |
| Authors: |
Vasin, V.1 vasin@mrsu.ru, Razin, V.2, Bezrukova, E.1, Korovin, D.1, Petrov, P.1, Somov, N.3 |
| Source: |
Russian Journal of Organic Chemistry. Aug2015, Vol. 51 Issue 8, p1144-1154. 11p. 1 Diagram, 2 Graphs. |
| Subject Terms: |
*PYRAZOLES, *HETEROCYCLIC compounds synthesis, *DIPHENYL, *ACRYLONITRILE, *ETHER (Anesthetic), *METHOXYCARBONYL group, *CYANO group |
| Abstract: |
Vinyl phenyl sulfone, methyl ( E)-3-(phenylsulfonyl)- and methyl ( E)-3-( p-tosyl)acrylates, ( E)-3-(phenylsulfonyl)- and ( E)-3-( p-tosyl)acrylonitriles react in ethyl ether at 20°C with diphenyldiazomethane leading to the formation of the corresponding 5,5-diphenyl-3-(arylsulfonyl)- Δ-pyrazolines. Products containing a methoxycarbonyl or cyano group at treating with DBU in dichloromethane at 0°C suffer a dehydrosulfonation and are converted into 4-substituted 3,3-diphenyl-3 H-pyrazoles. The oxidation of the mentioned Δ-pyrazolines with activated manganese dioxide in benzene at 20°C leads to the formation of 4-methoxycarbonyl- and 4-cyano-substituted 5-arylsulfonyl- 3,3-diphenyl-3 H-pyrazoles respectively. The reactions of α-bromovinyl phenyl sulfones and a-bromovinyl methyl sulfones with diphenyldiazomethane afforded the corresponding 3-bromo- 5,5-diphenyl-3-sulfonyl-Δ-pyrazolines. The first among them at 20°C suffered spontaneous elimination of molecular nitrogen and converted into 1-bromo-2,2-diphenyl-1-(phenylsulfonyl)cyclopropane whose structure was established by X-ray diffraction analysis. The action of DBU on another Δ-pyrazoline resulted in the formation of the product of the Ramberg-Bäcklund reaction, 5-methylene-3,3-diphenyl-Δ- pyrazoline together with the product of hydrodebromination-isomerization, 5,5-diphenyl-3-(methylsulfonyl)- Δ-pyrazoline. [ABSTRACT FROM AUTHOR] |
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