Synthesis of Methylene Bisphosphonates from Carbon Disulfide and Phosphites via Desulfurization: A Mechanistic Study

Abstract

The reaction of carbon disulfide with an excess of sodium dialkylphosphite in an aprotic solvent led to the formation of the carbanion of methylene bisphosphonate and sodium thiophosphate. The mechanistic study of this unexpected reaction, using both ³¹ P NMR and ESR spectroscopy, suggests the formation of a radical intermediate able to abstract a hydrogen atom from the solvent.

Keywords:

• Dialkylphosphite
• desulfurization
• methylene bisphosphonate
• phosphonodithioformate
• thiocarbonyl radical

Dedicated to Professor Marian Mikołajczyk from the CBMiM PAN in Łódź, Poland, on the occasion of his 70th birthday.

Authors thank the “Ministère de la Recherche et des Nouvelles Technologies”, CNRS (Centre National de la Recherche Scientifique), the “Région Basse-Normandie,” and the European Union (FEDER funding) for financial support.

Notes

^a Not isolated.