IMPROVED PREPARATIONS OF THIOPHOSPHITES AND THIOPHOSPHONATES

摘要

Improved methods for converting phosphite or phosphonate esters into corresponding thiophosphites or thiophosphonates and for synthesizing specif ic thiophosphite and thiophosphonate compounds so produced are disclosed and claimed. The methods start from phosphite diesters using P4S10 as the thionation reagent. The reaction mixture is refluxed until the reaction is complete and may be followed by separation and chloroformate ester phosphonation steps to produce pure thiophosphonocarboxylate triesters. Alternatively, these esters may be prepared directly by action of P4S10 on t he corresponding phosphonocarboxylate esters. The former method was used to prepare dimethyl thiophosphite and thence trimethyl thiophosphonoformate, a key intermediate in synthesis of salts of thiophosphonoformic acid, which ha ve anti-viral properties.