" Reactions of Organophosphorus Reagents with Active Centers in Some Organic Compounds"

Abstract

Part (1) : Reactions of Active and Stabilized Phosphonium Ylides with Isothiocyanate and Isocyanate Derivatives. Synthesis of Phosphoranylidene, Thietane, Thiazinane, Azetidine, Acid ester and Amide Compounds as Potent Chemo Preventative Agents. Phosphonium ylides have proved to be extremely useful reagents in the field of organophosphorus chemistry. They are nucleophilic reagents and their electronic structure is generally described as a resonance hybrid (a→b). Their reactivity varies according to the

substituent attached to the carbon end of the dipole. They have been classified as either active or stable. Active ylides must be prepared and handled under an inert gas. So the aim of this work can be presented according to the following sequences: 1- Synthesis of the active phosphacumulenes, namely, (2-oxovinylidene)- (2a) and (N-phenyliminovinylidene)- triphenyl-phosphorane (2b). Which are represented by the resonance structures 2A and 2B. 2- Preparation of the stable ylides, namely, methoxycarbonyl- (11a), ethoxycarbonyl-(11b) and acetyl- methylenetriphenyl-phosphorane (11c).