Patent GB-1244910-A (GB)
Title: Preparation of (cis-1,2-epoxypropyl)phosphonic acid, derivatives thereof and intermediates therefor
Inventor: CHRISTENSEN BURTON GRANT
IPC: A01N57/24
Filed: 1969-05-12
Abstract: 1,244,910. [cis - 1,2 - Epoxypropyl)phosphonic acid derivatives and intermediates therefor. MERK & CO. Inc. 12 May, 1969 [15 May, 1968], No. 23983/69. Heading C2C. (Cis - 1,2 - epoxypropyl)phosphonic acid or an ester, halide or salt thereof is obtained by oxidizing (cis - 1,2 - epoxypropyl)phosphonous acid or an ester, halide or salt thereof. The latter may be the () phosphonous compound in which case the phosphonic product is in the () form or the () phosphonous compound may first be separated (e.g. by use of an optically active amine) into its (+) and (-) enantiomers which are then separately oxidized to give the ( + ) or (-) phosphonic product respectively. The invention also includes as novel compounds (cis - 1,2 - epoxypropyl) - phosphonous and -thiophosphonous compounds of the formula in which X is O or S, X<SP>1</SP> is halogen, OH, SH or - OR and Y is halogen, OH or -OR where R is an aliphatic, cycloaliphatic, aromatic, or aromatictype heterocyclic group or an equivalent of an inorganic or organic salt-forming cation. Where X<SP>1</SP> is OH or SH the compounds exist essentially in the tautomeric form of Formula 1A. The phosphonous compounds I and IA may be obtained by either (1): treating a compound of the formula CH 3 CH = CH.P(X<SP>1</SP>)(Y) or CH 3 CH=CH-P(X)(Y)(H) with an acylating agent e.g. acetyl-, propionyl- or butyrylchloride, to obtain a compound of the formula wherein Q is an acyl group, e.g. an alkanoyl or aroyl group, epoxidizing the product e.g. with hydrogen peroxide and sodium tungstate to give a novel compound of the formula which is then deacylated, e.g. by alkaline hydrolysis; (2) by acidic hydrolysis of a diester of cis - 1 - propenyl phosphonous acid, e.g. di-nbutyl phosphonite, neutralizing with benzylamine to form cis - 1 - propenylphosphonous acid benzylammonium salt, and epoxidizing the latter e.g. with H 2 O 2  and sodium tungstate to form ()(cis - 1,2 - epoxypropyl) phosphonous acid benzylammonium salt or (3) by reduction of O,S - dialkyl - (cis - 1,2 - epoxypropyl) phosphonothioate, e.g. by contacting a () or (-) O,S - dialkyl (cis - 1,2 - epoxypropyl) phosphonothioate with Raney nickel in dioxane an alkyl () or (-) (cis - 1,2 - epoxypropyl) phosphonite is obtained and the solution thereof is basified with NaOH to yield sodium () or (-) cis - 1,2 - epoxypropyl) phosphonite. The oxidation of the phosphonous compound I or IA to the phosphonic compound may be carried out in water or other suitable solvent and a large number of suitable oxidizing agents are specified, the preferred agents being H 2 O 2 , iodine in the presence of water, silver oxide, or a mixture of H 2 O 2  and sodium tungstate. when the oxidation product is a halide of the phosphonic acid it may be converted to a salt of the acid by alkaline hydrolysis and when the product is an ester it may be converted to the acid or salt thereof by various methods, e.g. acid and/or base hydrolysis, photochemical reaction, hydrogenolysis, or conversion to a trimethylsilyl derivative followed by hydrolysis. Dibutyl cis-trans mixture -1-propenyl phosphonite is obtained by reacting 1 - propenyl magnesium bromide [prepared from 1 - bromopropene (cis/trans ratio 2 : 1) with magnesium] with dibutyl chlorophosphite in tetrahydrofuran. The phosphonite product may be separated into the cis and trans isomers by fractional distillation.