GB820401A - Improvements in and relating to heterocyclic phosphorus-containing carboxylic esters - Google Patents

Abstract

Heterocyclic phosphorus - containing carboxylic esters having the structure <FORM:0820401/III/1> wherein R, R1, R2, R3, R4 and R5 are hydrogen atoms or alkyl radicals, n is 0 or 1, R6 and R7 are hydrogen atoms or lower alkyl or alkenyl radicals having 1 to 4 carbon atoms or C6H5-, -CN, -Cl, -COOR9 or -CH2COOR9 radicals wherein R9 is an alkyl, cycloalkyl, alkoxyalkyl, aralkyl, aryl, or alkaryl radical and R8 is a hydrogen atom, a lower (C1-C4) alkyl radical, monocyclic aromatic hydrocarbon radical or a -Cl, -CN, -COOR9 or -CH2COOR9 radical wherein R9 is as defined above or is a hydrogen atom (see Group IV (b)), may be used as corrosion inhibitors or petroleum additives.ALSO:Heterocyclic 1,3 - dioxa - 2 - thiono - 2 - phosphacyclo - alkylthio carboxylic esters containing phosphorus in the heterocyclic ring are obtained by reacting a heterocyclic dithiophosphoric acid of the formula <FORM:0820401/IV (a)/1> wherein R, R1, R2, R3, R4 and R5 designate a hydrogen atom or an alkyl group and n is 0 or 1 with an ester of an alpha,beta-olefinically unsaturated carboxylic acid at a temperature between -20 DEG C. and 150 DEG C. The invention also comprises heterocyclic phosphorus-containing esters having the formula <FORM:0820401/IV (a)/2> wherein R, R1 to R5 and n are as defined above, R6 and R7 designate a hydrogen atom or an alkyl radical, or a lower (C1-C4) alkyl or alkenyl radical or a phenyl, -CN, -Cl, -COOR9 or -CH2COOR9 radical wherein R9 is an alkyl, cycloalkyl, alkoxyalkyl, aralkyl, aryl, or alkaryl radical, and R8 is a hydrogen atom, a lower (C1-C4) alkyl radical, a monocyclic aromatic hydrocarbon radical or a -Cl, -CN, -COOR9 or -CH2COOR9 radical, wherein R9 is as defined above or is a hydrogen atom. These products are obtained by a process as defined above in which the unsaturated ester reactant has the formula CR6R7=CR8COOR9, wherein R6, R7, R8 and R9 are as defined above. The process is usually carried out in the presence of an inert distillable organic solvent and an aliphatic tertiary amine such as triethylamine, or an alkali metal hydroxide or carbonate may be used as catalyst. A polymerization inhibitor, e.g. hydroquinone may also be present. Specified solvents which may be used are ethyl acetate, amyl acetate, 2-ethylhexyl acetate, methyl propionate, methyl and ethyl butyrates, acetone, methyl isobutyl ketone, dioxane benzene, toluene, xylenes, chlorobenzene, nitrobenzene, carbon tetrachloride, chloroform, trialkyl phosphates, e.g. triethyl and tri-(2-ethylhexyl) phosphates, acetonitrile and propionitrile. The products can be recovered from the reaction mixture by fractional distillation under vacuum to remove any unreacted starting material solvent and by-products, but the mixture is preferably first washed with dilute sodium bicarbonate and then with water prior to the distillation step, the product remaining as still residue. Specified unsaturated ester starting materials are the methyl, ethyl, butyl, hexyl, 2-ethylhexyl, octyl, decyl, tetradecyl, octadecyl, phenyl, benzyl, cyclohexyl, ethoxyethyl, and butoxyethyl esters of acrylic, methacrylic, alpha-ethacrylic, crotonic, tiglic, alpha-ethylcrotonic, sorbic, alpha-methyl sorbic, cinnamic, 2-chloroacrylic, 2-cyano-3-phenyl acrylic, 2-chlorocrotonic, and 2-cyano-3-phenylcrotonic acids and the corresponding mono- and diesters of alpha, beta-unsaturated di- and polycarboxylic acids such as maleic, fumaric, methylenemalonic, methylenesuccinic, benzylidenemalonic, aconitic, citraconic, ethylenetetracarboxylic, mono- and dichloromaleic, monocyanomaleic and 2,3-dicyanomaleic acids. Examples are given for the production of (1) diethyl 1,3-dioxa - 5 - ethyl - 4 - propyl - 2 - thiono - 2 - phosphacyclohexylthiosuccinate; (2) diethyl 1,3-dioxa - 4,4,5,5 - tetramethyl - 2 - thiono - 2 - phosphacyclopentylthiosuccinate; (3) diethyl 1,3 - dioxa - 2 - thiono - 4,4,6 - trimethyl - 2 - phosphacyclohexylthiosuccinate; (4) diethyl 1,3-dioxa - 4 - methyl - 2 - thiono - 2 - phosphacyclophenylthiosuccinate; (5) 2 - (2 - carbethoxy - ethylmercapto) - 5,5 - diethyl - 2 - thiono - 1,3,2-dioxaphosphorinane; (6) 2 - (2 - carbomethoxy-2 - methylethylmercapto) - 5,5 - diethyl - 2 - thiono - 1,3,2 - dioxaphosphorinane; and (7) 2 - (2 - carbobutoxy - 1 - methylethylmercapto)-5,5 - diethyl - 2 - thiono - 1,3,2 - dioxaphosphorinane. The specified products of Examples (1) to (4) are obtained by reacting diethyl maleate, with the appropriately substituted heterocyclic dithiophosphoric acid and those of Examples (5) to (7) by reacting ethyl acrylate, methyl methacrylate and n-butyl crotonate respectively with the appropriately substituted heterocyclic dithiophosphoric acid. The products are useful as pesticides, as plasticisers for synthetic resins, as corrosion inhibitors, flotation agents and petroleum additives. Specification 759,334 is referred to.ALSO:Heterocyclic phosphorus - containing carboxylic esters having the structure <FORM:0820401/VI/1> wherein R, R1, R2, R3, R4 and R5 respectively is a hydrogen atom or an alkyl radical, n is 0 or 1, R6 and R7 respectively is a hydrogen atom or a lower alkyl or alkenyl radical having 1 to 4 carbon atoms or a C6H5-, CN-, Cl-, COOR9-, or -CH2COOR9 radical wherein R9 is an alkyl, cycloalkyl, alkoxyalkyl, aralkyl, aryl, or alkaryl radical and R8 is a hydrogen atom, a lower (C1-C4) alkyl radical, a monocyclic hydrocarbon radical, a Cl-, CN-, COOR9- or -CH2-COOR9 radical wherein R9 is as defined above or is a hydrogen atom (see Group IV (b)) may be used as pesticides, e.g. in the form of aqueous suspensions.