Process for the preparation of O,O-dialkylthionophosphoric acid chlorides
AssigneeCiba-Geigy Corporation
InventorZdenek Mazour
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Abstract
Preparation of O,O-dialkylthionophosphoric acid chlorides of the formula ##STR1## in which R.sub.1 and R.sub.2 independently of one another are each an alkyl group having 1-6 carbon atoms, by reacting a dialkyl phosphite-chloride of the formula ##STR2## with sulfur in an inert solvent in the presence of a catalytic amount of titanium tetrachloride. The O,O-dialkylthionophosphoric acid chlorides of the above formula are valuable intermediates for the preparation of insecticidal active compounds.
Claims14
A process for the preparation of an O,O-dialkylthionophosphoric acid chloride of the formula I ##STR5## in which R.sub.1 and R.sub.2 independently of one another are each an alkyl group having 1-6 carbon atoms, by reacting a dialkyl phosphite-chloride of the formula II ##STR6## in which R.sub.1 and R.sub.2 are as defined above, with sulfur, which comprises carrying out the reaction of the dialkyl phosphite-chloride of the formula II with sulfur in an inert solvent in the presence of a catalytic amount of titanium tetrachloride.
Dependencies are inferred from the claim text.