Reaction of 1,2-Diaza-1,3-butadienes with Aminophosphorus Nucleophiles: A Practical Access to New Phosphorylated Pyrazolones

✍ Scribed by Orazio A. Attanasi; Graziano Baccolini; Carla Boga; Lucia De Crescentini; Gianluca Giorgi; Fabio Mantellini; Simona Nicolini

• Publisher: John Wiley and Sons
• Year: 2008
• Tongue: English
• Weight: 234 KB
• Volume: 2008
• Category: Article
• ISSN: 1434-193X
• DOI: 10.1002/ejoc.200800856

✦ Synopsis

Abstract

The reaction of 1,2‐diaza‐1,3‐butadienes with dibenzyl diisopropylphosphoramidite, methyl tetraisopropylphosphorodiamidite or tris(dimethylamino)phosphane under solvent‐free conditions gave stable α‐phosphoranylidene‐hydrazones that, in turn, were transformed into the corresponding 5‐oxo‐4‐phosphoranylidene‐4,5‐dihydro‐1__H__‐pyrazoles. X‐ray diffraction analysis of one of these derivatives is reported. α‐Phosphoranylidene‐hydrazones, derived from the reaction between 1,2‐diaza‐1,3‐butadienes with dibenzyl diisopropylphosphoramidite, were converted by hydrolytic cleavage into (E)‐hydrazono‐phosphonates, which are useful for the preparation of the corresponding (3‐oxo‐2,3‐dihydro‐1__H__‐pyrazol‐4‐yl)phosphonamidates.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)