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Chlorodiazaphospholines as intermediates in the synthesis of 1,2-dihydro-2-alkenyl-3H-pyrazol-3-ones and 2-pyrrolylacetates

✍ Scribed by Graziano Baccolini; Daniele Biondi

Publisher
John Wiley and Sons
Year
1993
Tongue
English
Weight
574 KB
Volume
4
Category
Article
ISSN
1042-7163

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✦ Synopsis

New derivatives of 1,2-dihydro-2-alkenyl-3H-pyrazoC 3-ones 6 and 7 have been synthesized at room temperature by a one-pot two-step reaction of PCZ,, a ketone methylhydrazone, and a f3-keto ester. With ketone methylhydrazones bearing at least a phenyl group in the a-positions to the C=N bond and in the second step p-keio esters, such as propionyl-or butyrylacetates, we obtained 2-pyrrolylacetates 8 as unexpected products together with pyrazolones 7. The ratio of the two products depends on the nature of the groups in the a-positon to the C=N bond. A chlorodiazaphospholine 1 is the key intermediate of this new reaction, and a plausible mechanism of f o m ation of the azaheterocycles is reported.

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