| 摘要 |
1303841 Preparing thiophosphonic acid esters STAUFFER CHEMICAL CO 15 Jan 1970 [27 Jan 1969] 2024/70 Heading C2P A pesticidal ester of the formula in which R is C 1 -C 6 alkyl, X is O or S and A is phenyl or substituted phenyl, wherein the substituents are selected from Cl, C 1 -C 4 alkyl, C 1 -C 4 alkoxy, NO 2 or CN is obtained by reacting a compound of the formula with phosphorus pentasulphide in an organic solvent, e.g. toluene, at 90-130‹ C. at atmospheric pressure in the presence of a catalyst selected from aniline, dimethyl aniline, 2À, 3- or 4-picoline, pyridine and diammonium hydrogen phosphate. The compound ROP(O)(XA)R is prepared by a stepwise process which comprises (1) isomerizing a trialkyl phosphite of the formula (RO) 3 P in the presence of an iodine-containing catalyst, e.g. iodine or an alkyl iodide to form a phosphonate (RO) 2 P(O)R, (2) reacting the latter with COCl 2 to form a chloridate (RO)(R)P(O)Cl and (3) reacting the chloridate with an alkali metal salt of the formula MXA wherein M is an alkali metal. Step (2) may be effected in the presence of a catalyst such as dimethyl formamide or under increased pressure without the use of a catalyst and step (3) is suitably effected in the presence of a solvent such as toluene and can be carried out batchwise or continuously. |
