CA1058631A - Process for the preparation of the o,o-dimethyl-o-(2,2-dichlorovinyl) ester or the o,o-diethyl-o-(2,2-dichloro-vinyl) ester of thionophosphoric acid - Google Patents

Abstract

PROCESS FOR THE PREPARATION OF THE O,O-DIMETHYL-O-(2,2-DICHLOROVINYL) ESTER OR THE O,O-DIETHYL-O-(2,2-DICHLORO-A b s t r a c t The present invetion relates to an unobvious process for the preparation of the 0,0-dimethyl-0-(2,2-di-chlorovinyl) ester or the 0,0-diethyl-0-(2,2-dichloro-vinyl) ester of thionophosphoric acid, which esters are known as insecticides.
It has already been disclosed in the literature that the 0,0-dimethyl-0-(2,2-dichlorovinyl) ester of thiono-phosphoric acid can be obtained when the 0-(2,2-di-chlorovinyl) ester of thionophosphoric acid dichloride is reacted with methanol.

Description

105863~

~ype IVa The present invention relates to an unobvioue proceee ior the preparation oi the 0,0-dimethyl-0-(2,2-dlchloro-vinyl) ester or the 0,0-diethyl-0-(2,2-dichlorovinyl) ester oi thionophosphorio acid, which e~ter~ aro known as insecticides It has already been discloeed in the literaturo that the 0,0-dimethyl-0-(2,2-dichlorovinyl) ester Or thiono-phosphoric acid oan be obtained when the 0-(2,2-diohloro-vinyl) e~ter oi thionophosphori¢ acid dichloride i8 reaCtea with methanol However, this procees has a ~u~bor Or disadvantages ~hus, the 0-(2,2-dichlorovinyl) eoter Or thionophoephoric acid dichlorlde which ie required ae tho starting material is obtained in poor ylelds (less than ~0%
oi theory) irom the oorresponding o~ygen compound by ro-action with phosphorus penta~ulphide only at very high temporaturos (about 150C) Moreover, the iurthor r-action oi the dichloride with methanol can b~ carrlod out oDly with a yield oi 50~ oi theory, 80 that the total yiold ior both stagos ie about 15% The ueeiulnese oi this procoss le thereioro llm1tod (eee D~-0~ (~erman Published 9p-ciiicatlo~)

2,150,108) It ie aloo knoxn that the compouDds prep ro~ aooor~
to the prooooe oi DT-~ (O-rma~ Publlehea 9p ciil~tlon) 1,058,046 aO not have tho etructuro oi 0,0~ lk~l-0-(2,2-dichlorovinyl) ~et-re oi thlonophoephoric-aci~ (eo~ D~-OB
(oermsn Publieh~ ~p-ciiication) 2,133,199) Moreo~or, it i8 etatoa in tho literature that lt l- not po~eiblo to propare the O,O-~imethyl-0-(2,2-di~hlorovinyl) e~tor o~ thlo~opho~phoric acid etarting ~rom di~ethyl thiol-~e ~ 16 253 - 2 - ~

105~631 phosphite and chloral since the reaction takeQ another course (see ~elgian Patent Specification 623,551 and Pelchowicz, J.Chem.Soc. 1961, page 241 et sea.). The isomeric compound oi the iormula O
(CH30)2P-S-CH=ccl2 (I) is obtained as the end product.
It i~ known, ~rom DT-OS tGerman Published Specl-ficatlon) 2,150,108, pages 3 and 4, that the customary method~ for obt~ining vinyl phosphates and cortain thio-phosphatee fail in the caee of the preparation of the correspondin~ thiono compound of the ~ormula S

(C~ O)2P-O-CE CC12 (II).

According to that epecification, the claesiaal Perkov reaction, which ie employed for tho preparation oi ~inyl phosphatee, does not lead to the corr-sponding vinyl thio-phosphatee. When a trialkyl thiophosphit- (tri~kyl phos-phorothioite) ie reacted with ahloral the produ¢t which reeult~ irom thie reaction ie an O,~-dialkyl-O-halogono-vinyl thiolphosphate. Other auetom~ry prooe~eos are aleo etated to be unsuitabl~.
It ie also known that the aompound oi the iormula (II) iB obtained, acaording to DT-O~ (~erman Publlshed ~peol-fication) 2,238,921, by ~llowing ahloral and an alkali metal alcoholate to act on dimethyl thiophoephit- in the preaenca o~ a baee as the ¢atalyet. This proaeee alBO
entails aerta~n dliiiaultie~, einae it ie known that 0,0-dlalkyl eet-re o~ thlophoephoroue aold iorm alka1i metal 105863~
salts in lnert solvents, which salts are saponified by moisture or by treatment wlth w~ter in a short time to give salts of 0-monoalkyl esters of thiophosphorous acid. The alkali metal salts also form in excess alcohol on the addition of alcoholate (see Houben ~eyl, Volume XTI /2, page 97).
In all cases part of the 0,0-dialkyl ester of thiophosphorous acid is withdrawn from the actual reaction by this side reaction of alternative reaction.
There is therefore great interest in a process which possesses none of these defects and which eliminates the existing difficulties.
The present invention provides a process for the preparation of the 0,0-dimethyl-0-(2,2-dichlorovinyl) ester or 0,0-diethyl-0-(2,2-dichloro-vinyl) ester of thionophosphoric acid, in which the 0,0-dimethyl ester or the 0,0-diethyl ester, respectively, of 1-hydroxy-2,2,2-trichloroethane-thionophosphonic acid, of the general formula S

(RO)2P-CH-CC13 (III) OH
in which both R groups represent either a methyl radical or ethyl radical, is treated at -20 to 100C with a solution tà) of an equivalent amount of an alkali metal alcoholate or (b) of an alkali metal hydroxide or alkali metal carbonate in an alcohol.
The reaction is preferably carried out with methanol or ethanol in order to avoid trans-esterification.
It is to be regarded as extremely surprising that the process according to the invention leads to the desired ester because, in view of the state of the art, a product ~ .
~ ~ - 4 -105~9Ui31 corresponding to the formula (Ij, or ite O,O-diethyl analogue, would have been expected.
The proces~ according to the invention hae a number of advantages and represents a new route, which w~ not hitherto known and which also wae not regardod ae being capable oi realisation, to the desired O,O-dimethyl-0-(2,2-dichloro-vinyl) eeter and the O,O-diethyl-0-(2,2-di¢hlorovinyl) estor of thionophosphori-c acid. The new process dispenses with the u~e of expeneive cryet~1line (solid) sodium alcoholate (compare DT-OS (German Published 8peciiication) 2,150,108, page 10). The O,O-dimethyl ester or O,O-diethyl estor oi 1-hydroYy-2,2,2-trichloroethane thionophoephonic a¢id, which i~
required a~ tho starting material, can be propared in a high yield in a technically eimple mannor, whereae the inter-mediate required according to DT-O~ (oorman Publiehed Speciiication) 2,150,108 is obtai~Pb}e only in about 30%
yield and by meane oi a procees which indw trislly can be ¢ontrolled only with diiiiculty. The a¢ceseibility oi the intermediate used in the prosont invention ie thoreiore much better than that o~ the intormediate roguired according to DT-O~ (~orman Publiehed ~peciiication) 2,150,108.
Moreo~or, the prooese a¢cording to thie imontion has the advantage that it ie poeeiblo to diepenee ~ith the use of e~poneiv eolid eodium alcoholato and to uee lnetead a solution of eodlum methglato or eodium ethylato in methanol or ethanol, roepoctively. Moreo~er, 2 molee oi aodium mothylate are requirod por mole oi tho intermediate aocording to D~-OS (~orman Publlehod ~p-ciilcatlon) 2,150,108, ~hereas only 1 mole of eodlum alcoholate die-solved in methanol or ethanol ie roquirod aecording to the ~e A 16 253 - 5 -~058631 invention, which signifiee a con~iderable ~aving.
A further advantage of the proce~s according to the invention is that, according to one variant, the use of sodium alcoholate is completely dispensed with and a ~olution of an alkali metal hydroxide or alkali metal carbonate in methanol or ethanol may be employed with equal suc¢e~s.
If the 0,0-dimethyl ester of 1-hydroxy-2,2,2-trichloro-ethane-thionopho~phonic acid i~ used as the starting material and a solution of an alkali metal hydroxide or P1kali metal carbonate in methanol is used, the course of reaction can be represented by the following equ~tion:
S
(CH30)2P-C,H CC13 (III) alkali metal hydroxide S
or alkali metal "
carbonate in methanol (¢~ 0)2P-0-CH--¢Cl2 (II) The 0,0-dimethyl ester and-0,0-diethgl ester of 1-hydro~y-2,2,2-trichloroethane-thionophosphonic acid, which are to be ueed ae the atarting materials, ha~e not yet been described hitherto in the literature but can be obtained irom dimethyl thiolphosphite or diethyl thiolphosphite reepectively and chloral according to a proposal which doo~ not conetltute part o~ the state o~ the art and which i~ couLter to current teaching (Pelchowicz; J.ahem.~oc. 1961, page 241 et ~gL).
~he process according to the inv-ntlon can bs carried out without or with the additional use of colvents. Solvonte which can be used are all inert orgP~c ~olvents, especially hydrocarbon~, ~uch as benz1ne, ben~ene and toluene; ethers, ~e A 16 253 - 6 -such a~ diethyl ether and dioxane; chlorinated hydro-carbons, ~uch as methylene chloride and ethylene chloride;
ketonee, euch as acetone and butanone; and nitriles,euch as acetonitrile and benzonitrile. CertQin alcohols, such a~
methanol, ethanol, propanol and butanol, can aleo be used as ~olvente. Appropriately, preference i8 given to methanol or ethanol since, in thi~ way, tran~-esteri~ications are excluded.
The reaction is carried out at a temperature between -20 and +100C, preierably between +10 and ~20C; it is also generally ei~ected under normal preseure.
When carrying out the proces~ according to the invention, 1 mole of alkali metal hydroxide or ~ mole o~ alkali metal carbonate ie preierably employed per mole oi the 0,0-dimethyl ester or 0,0-diethyl ester oi 1-hydro~y-2,2,2-trichloroethane-thionophoephoric a¢id. Relati~ely large deviatione from thie ratio result in ~n impure product and a high loee in yield.
~e already mentioned, the 0,0-dimethyl-0-(2,2-di-chlorovingl) ester ~n~ 0~ 0-diethyl-0-(2,2-dichlorovingl) eeter o~ thionophosphoric acid, which can be prepared according to the procese, are ueed, beoau6e o~ thelr properties in theso fields, as pest control agente, above all as ineecticides, especially ior plant protection and in the iield oi hygiene ~n~ the protection oi stored proaucts.
~o the sucking ineecte there belong, in the main, aphide (~æ~didae) euch as the green peach aphid (MYzue per~icao), the bean aphid (Doralis fabae), the bird cherry a~hid ( ho~aloai~hum adi~, the pea aphid ( acrosi~hum isi) and the potato aphid (Nacrosi~hum ~olaniiolii), the currant ~all aphid (~rv~to~v~u~ korschelti), the roey appl~ aphid ~9 ~ 16 253 _ 7 _ (Sa~saPhis mali) the mealy plum aphid (~Yalo~terus ~rundinis) and the cherry black-ily (~YZU8 cerasi); in addition, ~calee and mealybugs (Coccina), for example the ole~nder scale (~nidiotus hederae) and the soit scale (Lecanium hesneridum) as well a3 the grape mealybug (Pseudococcus maritimu~);
thrips (ThvsanoPtera), such as ercinothriPs emorali~, and bugs, ~or example the beet bug (Piesma auadrata), the red cotton bug (DYsdercu~ intermediu~), the bed bug (Cimex lectularius), the a~sassin bug (Rhodnius ProlisNs) and Chaga~' bug (?riatoma infestans) and, further cicadas, such as Eusceli~ bilobatus and NePhotettix bi~unctatus.
In the case oi the biting insects, above all there should be mentioned butterily caterpillars (~eidoDtera) such as the diamond-back moth (Plutella macullnennis), the gip~y moth (~mantria disnar), the brown-tail ~oth (EuDroctis ¢hr~sorrhoea) and tent caterpillar (~laco~oma neustria);
iurther, the cabbage moth (Mamestra bra~sicae) and the cut-worm ( rotis se~etum), the large white butterily (Pieris bras~icae), the small winter moth (Cheimatobia brumsta), the green oak tortrix moth (Tortris viridana), tho iall army~orm ( anhY~ma fru~inerda) and cotton worm (Prodenia itura), tho ermine moth (~nonomeuta Dadella), the Mediterranean ilour moth (~nhestia kuhniella) and gr;eater wa~ moth (~alleria mello~ella).
The active compounds prepared acoording to the present invention oan bo converted into th- w ual iormNlations, suoh ae solutlons, emulsione, suepension~, powder~, paetoe and granulates. Theso may be produced in known m~nner, ior example by mixing the activo compounde with estendor~, that i~, liquid or ~olid or liqueiied gaseou~ diluonts or ~e ~ 16 253 - 8 -carriers, optionally with the use of suriace-active agents, that is, emulsi~ying agents and/or dispersing agent~ and/or foam-forming agents. In the case of the use of water as an extender, organic ~olvent~ can, for example, al~o be used as auxiliary solvents.
A~ liquid diluents or carriers, there are preierably used aromatic hydrocarbons, such as xylenes, toluene, benzene or alkyl naphthalenes, chlorinated aromatic or aliphatic hydrocarbons, such as chlorobenzenes, chloroethylenes or methylene chloride, aliphatic hydrocarbons, such as cyclo-he~ane or paraffins, for example mineral oil fractione, alcohols, such as butanol or glycol as well as theirethers and esters, ketones, such as acetone, methyl ethyl ketone, methyl isobutyl ketone or cycloheganone, or strongly polar sol~ents, such as dimethyl formamide, dimethyl sulphoside or acetonitrile, as well as water.
~y liqueiied gaseous diluents or carriers are meant llquids which would be gaseous at normal temperatures and preesures, for egample aerosol propellants, such as halo-genated hgdrocarbons, ior example freon.
As solid diluents or carriers, there are preierably w ed ground natural minerals, such as kaolins, clay~, talc, chal~, quartz, attapulgite, montmorillonite or diatomaceous earth, or ground synthetic minerals, such as highly-dispersed silicic acid, alumina or silicates.
Preierred egamples of emulsiiying and ioam-iorming agents include non-ionic and anionic emulsi~iers, such as polyosyethylene-iatty acid esters, polyogyethylene-iatty aclohol ethers, for e~ample alkylarylpolyglycol ethers, al~yl sulphonates, alkyl ~ulphates and aryl sulphonates as ~e A 16 253 ~ 9 ~

105863~

well as albumin hydrolyzation products; and preferred examples of disper~ing agents include lignin sulphite wa~te liquor~ and methyl cellulose.
The active compounds according to the invention can be present in the formulations as a mi~ture with otner active compounds.
In general, the formulations contain from 0.1 to 95 per cent by weight of active compound, preferably from 0.5 to 90 per cent.
The active compounds can be employed as such, in the form of their formulations or in the use forms prepared therefrom, such as ready-to-use solutions, emulsions, fo~ms, suspension~, powders, pastes, soluble powder~, dusting agents and granules. They may be used in the customary manner, for example by squirting, spraying, atomising, dusting, scatter-ing, fumigating, gas~ing, watering, dressing or encrusting.
~he active-compound concentrations in the ready-to-w e preparation3 can be varied within fairly wide ranges. In general, they are between 0.0001 and 10%, preferably between 0.01 and 1%,by weight.
The active compounds can also be used with good succes~
in the ultra-low-volume (ULV) method where it is possible to apply formulations of up to 95% active compound or even to use the active compound by itself.
The present invention therefore also provides an in~ecticidal composition containing ae active ingredient a compound prepared according to the present invention in admixture with a solid or liquefied ga~eous diluent or carrier or in admixture with a liquid diluent or carrier containing a sur~ace-active agent.

~e A 16 253 - 10 -The present invention also provides a method oi combating insects which comprises applying to the inseets or an insect habitat a compound prepared according to the present invention alone or in the form oi a compositlon containing as active ingredient a compound prepared according to the present invention in admi~ture with a diluent or carrier.
The present invention further provides crops protected irom damage by insects by beig grown in areas in which immediately prior to and/or during the time oi the growing a compound prepared according to the present invention was applied alone or in admisture with a diluent or carrier.
It will be seen that the u9u31 methods oi providing a ~arvested crop m y be improved by the present invention.
The esamplee which iollow illuetrate the procees according to the present in~ention.
~am~le 1 (CH30)2P-0-C~=aal2 (II) 2.3 g oi eodium dieeol~ed in methanol were added drop-wiee at 10 to 20C to a solution oi 27.3 g (0.1 mole) oi the 0,0-dimethyl eeter oi 1-hydrosy-2,2,2-triehloroethsne-thionophoephonic a¢id in 50 ml of methsnol. The bateh wae etirred ior 15 minutes at 30C, ¢ooled and stirred into i¢e water. The aqueou~ solution was estraeted twice with methylene ¢hloride and the eombined methylene ¢hloride estracts wero wsehed once with wster and then drled. ~iter distilling oii the eol~ent under redu¢ed pre~eure, 23.5 g oi an oil, which, aceording to gss ehromatogrsphi¢ de-termination, eontained 92.4% oi the 0,OLdimethyl-0-(2,2-~e ~ 16 253 - 11 -~058631 dichlorovinyl) ester of thiophosphoric acid, were obtained.
The ¢rude product could be distilled. It boiled at 76 to 80C
under a pressure of 2 mm Hg; the refractive index ~2 wae 1.4964. The _tructure of the compound wae verified by NMR
spectro~copy.
Exam~le 2 S
(C~ 0)2P-0-C~=CCl2 (II) A ~olution eon~isting of 6.9 g of potassium carbonate, 20 ml of methanol and 20 ml of water wae added dropwi~e at 30C to a Rolution o~ 27,3 g (0.1 mole) of the 0,0-dimethyl eQter of 1-hydroxy-2,2,2-trichloroethane-thionophoephonic acid in 30 ml o~ methanol. The ~urther procedure was then as described in Example 1. 23.6 g o~ an oil, which, accord~ng to gas chromatographic determination, contained 58% oi theory of the 0,0-dimethyl-0-(2,2-dichloro~inyl) ester o~ thlophosphori¢ acid, were obtained.
~xam~le 3 (CH30)2P-0-C~=acl2 (II) A solution oi 21.6 g (0.54 mole) oi eodium hydrosido in 100 g o~ methanol was added dropwiee, whllet ~tirring and with e~ternal ooolin~, in the oourse oi 20 minutoe to a mixture of 137.0 g (0.5 mole) o~ 0,0-dimethyl 1-hydro~y-2,2,2-trichloroethane-thiophosphonate and 200 ml oi toluene, the internal temperature be$ng kept at between 15 and 20C.
~ter etirring for 1 hour at 20C, the reaotion misture wa~
extracted by ~h~king with ~our to ~i~e times 200 to 250 ml o~ water and the organio phase wae then dried with 25 g oi sodium sulphate and freed ~rom solvent in a rotary Le A 16 253 - 12 -~058631 evaporator under reduced pressure. On fraction~1 distillation the residue gave 95.5 g (80.5% oi theory) oi the O,O-dimethyl 0~2,2_dichlorovinyl)ester oi thiophoephori¢ acid as a colourless liquid with a boiling point oi 78C/2 mm Hg. The refractive index n19 was t.4990. Content according to gae ¢hromatogram : 99.2%.
~xamle 4 (C2H50)2P-o-aH=acl2 (IV) An ethanolic #olution containing 5 molee oi eodium ethylate was allowed to ilow, in the ¢ouree of one hour, into a solution of 1,508 g ( 5 moles) of O,O-diethyl 1-hydro~y-2,2,2-trichloroethane-thionopho~phonate in 2 1 of toluene, whilst stirring and with e~ternal cooling, at an internal temperature oi 15 to 20C. ~iter stirring 15. the mixture ior 1 hour, it was washed with water and dried and the eolvent was stripped ofi under roduced preeeure.
99~.1 g (75.0% oi theory) oi the O,O-diethyl,O-S 2,2-dlohloro-~inyl)eeter oi thionophoephori¢ a¢id remain ae a pale yellowieh ¢oloured liquid with a boillng point oi 89C/
2 mm Hg and a reira¢tive inde~ ~ 8 oi 1.4875.

~e ~ 16 253 _ 13 _

Claims (8)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A process for the preparation of the 0,0-dimethyl-0-(2,2-dichloro-vinyl) ester or 0,0-diethyl-0-(2,2-dichlorovinyl) ester of thionophosphoric acid, in which the 0,0-dimethyl ester or the 0,0-diethyl ester, respectively, of l-hydroxy-2,2,2-trichloroethane-thionophosphonic acid, of the general formula (III), in which both R groups represent either a methyl radical or ethyl radical, is treated at -20° to 100°C with a solution (a) of an equivalent amount of an alkali metal alcoholate or (b) of an alkali metal hydroxide or alkali metal carbonate in an alcohol.

2. A process according to claim 1, in which solution (b) is employed and methanol is used as the alcohol.

3. A process according to claim 1, in which solution (b) is employed and ethanol is used as the alcohol.

4. A process according to claim 1, 2 or 3 in which alkali metal hydrox-ide or alkali metal carbonate is treated with the 0,0-dimethyl ester or 0,0-diethyl ester of l-hydroxy-2,2,2-trichloroethane-thionophosphonic acid, one mole of alkali metal hydroxide or half a mole of alkali metal carbonate being employed for each mole of the hydroxy ester.

5. A process according to claim 1, in which the ester (III) is treated with a solution of sodium methylate in methanol or with a solution of sodium ethylate in ethanol,

6. A process according to any of claims 1,2 or 3, in which the reaction is carried out at temperatures between +10° and +20°C.

7. A process according to claim 1, 2 or 3 in which alkali metal hydroxide or alkali metal carbonate is treated at +10° to +20°C with the 0,0-dimethyl ester or 0,0-diethyl ester of 1-hydroxy-2,2,2-trichloroethane-thionophosphonic acid, one mole of alkali metal hydroxide or half a mole of alkali metal carbonate being employed for each mole of the hydroxy ester.

8. A process according to claim 1 in which the ester (III) is treated at +10° to +20°C with a solution of sodium methylate in methanol or with a solution of sodium ethylate in ethanol.