Facile Preparation of Oxodiperoxymolybdenum(Pyridine)(Hexamethylphosphoric Triamide) (MoOPH)

Abstract

The title compound is known and used as an oxidizing agent. The most useful application of it is the oxidation of the carban-ions obtained from esters, lactones, ketones, nitriles, aldehydes, sulphones and amides in order to obtain the hydroxy derivatives. The known method of synthesis of MoOPH involves the oxidation of MOO₃ obtain to MOO₅ with 30% hydrogen peroxide. We tried to MOO₅ according to procedure described by Vedejs and unfortunately about 50% of the unreacted MOO₃ had t o be filtered off from the MOO₅ solution after 3.5 h. stirring at 40°C, so the yield of MOO₅ HMPTH 0 was about 30%. We needed a bigger amount of title reagent and we started from molybdic acid monohydrate instead of MOO₃ and 30% hydrogen peroxide. The reaction appeared slightly exotherrnic and took place in half an hour at 4O°c. All molybdic acid was dissoled and gave a yellow clear solution of Moo₅. Addition of equimolar amount of HMPT gave the required MOO₅HMPTH₂O complex as a fine yellow crystalls in 61.9% yield. The complex after water removed in vacuum dessicator and the addition of pyridine according to the literature afforded Mo0₅PyHMPT, which was used succesfully in our hydroxylation reactions.