| Abstract: | Chlorination of the 4‐chloro(diisopropylamino)phosphino]pyrazole 1 leads to the dichlorophosphonium chloride 2 , which immediately after its formation transforms into the dichloro(diisopropylamino)phosphonio5(4)oxopyrazol‐4‐ylide‐5‐one] 3 , as a result of dealkylation through loss of ethyl chloride. Reactions of 3 with various nucleophilic reagents were studied. The partial hydrolysis of 3 in the presence of nitriles, resulting in new phosphorus‐containing cyclic systems, is of particular interest. It was demonstrated that chlorination of the P‐dichloropyrazolylphosphine A leads to the stable tetrachlorophosphorane 12 . The C P bond of 12 is broken upon heating. An X‐ray structure determination of compound 11b revealed a planar central heterocycle (mean deviation 0.029 Å). © 2003 Wiley Periodicals, Inc. Heteroatom Chem 14:452–458, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10177 |
