.alpha.-Hydroxyethylphosphinates, and their use as fungicides

#The present invention relates to .alpha.-hydroxyethylphosphinates, and their production and use.

#The said .alpha.-hydroxyethylphosphinates are representable by the formula: ##STR2## wherein X is a hydrogen atom, a chlorine atom or a bromine atom and R is an alkyl group, a lower haloalkyl group, a lower cycloalkyl group, a lower alkoxy(lower)alkyl group, a lower alkylthio(lower)alkyl group, a phenoxy(lower)alkyl group, a phenylthio(lower)alkyl group, a phenyl(lower)alkoxy(lower)alkyl group, a phenyl(lower)alkylthio(lower)alkyl group, a lower cycloalkyl(lower)alkyl group, a lower alkyl(lower)cycloalkyl group, a halo(lower)cycloalkyl group, a lower alkylthio(lower)cycloalkyl group, a lower alkoxy(lower)cycloalkyl group, a lower cycloalkyl(lower)cycloalkyl group, a lower alkoxy(lower)alkoxy(lower)alkyl group, a phenyl(lower)alkyl group, a halophenyl(lower)alkyl group, a lower alkylphenyl(lower)alkyl group, a lower alkoxyphenyl(lower)alkyl group, a phenoxyphenyl(lower)alkyl group, a phenylphenyl(lower)alkyl group, a dihalophenyl(lower)alkyl group, a di(lower)alkylphenyl(lower)alkyl group, a di(lower)alkoxyphenyl(lower)alkyl group, a tri(lower)alkoxyphenyl(lower)alkyl group, a naphthyl(lower)alkyl group or an anthracenyl(lower)alkyl group.

#In the above significances, the number of carbon atoms in the alkyl group is not more than 13. The term "lower" is generally intended to have not more than 8 carbon atoms, and the term "halo" is intended to mean chlorine, bromine, fluorine and iodine, inclusively. Preferred examples of R include C.sub.1 -C.sub.10 alkyl, C.sub.2 -C.sub.3 haloalkyl, C.sub.5 -C.sub.6 cycloalkyl, C.sub.1 -C.sub.3 alkoxyethyl, C.sub.1 -C.sub.2 alkylthioethyl, phenoxyethyl, phenylthioethyl, phenylmethoxyethyl, phenylmethylthioethyl, C.sub.3 -C.sub.6 cycloalkylmethyl, methylcyclohexyl, chlorocyclohexyl, methylthiocyclohexyl, methoxycyclohexyl, cyclohexylcyclohexyl, methoxyethoxyethyl, benzyl, halobenzyl, C.sub.1 -C.sub.4 alkylbenzyl, C.sub.1 -C.sub.4 alkoxybenzyl, phenoxybenzyl, phenylbenzyl, dichlorobenzyl, dimethylbenzyl, dimethoxybenzyl, trimethoxybenzyl, phenyl(C.sub.2 -CHD 3)alkyl, chlorophenethyl, methoxyphenethyl, methylphenethyl, naphthyl(C.sub.1 -C.sub.2)alkyl and anthracenylmethyl.

#Practical and presently preferred embodiments for production of the .alpha.-hydroxyethylphosphinates (I) are shown in the following Examples.

#A solution of .alpha.-hydroxyethylphosphinic acid (2.2 g) and 1-butanol (5.0 g) in benzene (30 ml) was heated for 3 hours with removal of water through a Dean-Stark apparatus. After cooling, the reaction mixture was washed with water, dried over magnesium sulfate and concentrated in vacuo to give 2.71 g (81.6%) of n-butyl .alpha.-hydroxyethylphosphinate (Compound No. 5).

#A 10% solution of diazomethane in ether was gradually added to a stirred and ice-cooled solution of .alpha.-hydroxyethylphosphinic acid (3.0 g) in tetrahydrofuran (10 ml) until the color of the solution turned to yellow. After 10 minutes, the solvent was evaporated in vacuo. The residue was distilled to give 2.28 g (67.3%) of methyl .alpha.-hydroxyethylphosphinate (Compound No. 1).