Process for the production of (plus)-cis-, (plus)-trans-mixed chrysanthemic acid
United States Patent [1 1 Yoshioka et al.  
 [73] Assignee: Sumitomo Chemical Company,  
 Limited, Osaka, Japan [22] Filed: Oct. 17, 1972 [21] Appl. No.: 298,247  
 [30] Foreign Application Priority Data Oct. 19, 1971 Japan 46-83120 [52] US. Cl. 260/514 H; 260/468 H; 424/306 [51&#39;] Int. Cl. C07c 51/42 [58] Field of Search 260/514 H, 468 H, 468 CA [56] References Cited UNITED STATES PATENTS 3.739.019 6/1973 Veda 260/514 FOREIGN PATENTS OR APPLICATIONS 2.043.173 411971 Germany &#39;260/5I4 [111&#39; 3,879,451 [451 Apr. 22, 1975 OTHER PUBLICATIONS Eliel, Sterochemistry of Carbon Compounds, pp. 49-53 (1962).  
 Primary Examiner-Robert Gerstl Attorney, Agent, or FirmStevens, Davis, Miller &amp; Mosher [57] ABSTRACT An optical resolution process for preparation of optically active (+)-cis-, (+)-tr&#39;ans-mixed chrysanthemic acid which comprises resolving a mixture of (i) -cisand (i)-trans-chrysanthemic acids by using as a resolution agent an optically active organic amine having the formula,  
 l NH2- wherein R and R are individually a hydrogen atom or a lower alkyl.  
 4 Claims, No Drawings PROCESS FOR THE PRODUCTION OF (PLUS)-ClS-, (PLUSl-TRANSMIXED CHRYSAN THEMIC ACID This invention relates to a process for preparation of (+)-cis-. (+)-trans-mixed chrysanthemic acid. More particularly, the invention pertains to a process for preparing (+)-cis, (+)-trans-mixed chrysanthemic acid with commerical advantages by subjecting a mixture of (i)-cisand (i)-trans-chrysanthemic acids to optical resolution using as a resolution agent optically active organic amine represented by the formula (l).  
 wherein R and R are individually a hydrogen atom or a lower alkyl.  
  Heretofore. the optical resolution of chrysanthemic acids has chiefly been carried out according to any of processes in which (i)-transand (i)-cischrysanthemic acids are individually treated with an optically active amine to obtain optically active forms of the respective acids. as disclosed in the following referential literature materials:  
 1. Campbell and Harper: Journal of the Science of Food and Agriculture. 3. 189. (1952) 2. French Patent No. 1,536,458  
 3. Japanese Patent Publication No. 20.382/71 4. Japanese Patent Publication No. 30.832/71 On the other hand. chrysanthemic acid which is most economically produced is a mixture of (i)-cisand (i)-trans-chrysanthemic acids which can not be easily separated from each other. Some esters of (:t)-cischrysanthemic acid with specific alcohols can be used as insecticides which are less toxic to mammmals and more active in knock-down effect than the corresponding esters of (+)-trans-chrysanthemic acid.  
  Moreover, in specific examples a mixture which consists of specific alcohol esters of (+)-cis-chrysanthemic acid and (+)-trans-chrysanthemic acid exhibits more potensive insecticidal activities than those of the corresponding ester of (+)-trans-chrysanthemic acid or (+)-cis-chrysanthemic acid.  
  Accordingly, the present process for production of the mixture of (+)-cis-chrysanthemic acid and (+)-trans-chrysanthemic acid from the mixture of (i)- cisand (i)-trans-chrysanthemic acids is highly valuable from industrial point of view. However, there has been no precedent art which is capable of successfully dealing with this problems. For instance, in the example which is described in the referential literature (2). (i)cisand (i)-trans-chrysanthemic acid (cis trans ratio is 3 7) is subjected to the optical resolution with D(--)-threol-p-nitro-phenyl-Z-dimethylamino-1,3- propanediol and only (+)-trans-chrysanthemic acid is obtained. whereby no (+)-cis-chrysanthemic acid is found in the resolution product.  
  The present inventors have carried out a series of extensive studies on the process for obtaining the mixture of (+)-cis and (+)-trans-chrysanthemic acid. in which a number of available optically active amines were attempted for this purpose. Among them the aforesaid amines, in particular, (+)-l-phenyl-2-p-tolylethylamine which is used in theresolution process of (i)-trans-chrysanthemic acid to obtain the (+)-trans isomer in the referential literature (3) were found to be unique in that the amines could solve the subject problem with the following satisfactory results: when a mixture comprising (i)-cisand (i)-trans-chrysanthemic acids in a ratio within a specific range is subjected to optical resolution with one of the aforesaid amines, there are obtained as precipitation a saltconsisting of (+)-cisand (+)-trans chrysanthemic acids and the amine. and under proper conditions cis-trans ratios of the (+)-acids are essentially equal to the ratios in the (i)-acids which are submitted to the optical resolution.  
  More beneficially. the emphasis is put forth that the (+)-cisand (+)-trans-chrysanthemic acids whichlare obtained after single resolution procedure are often highly pure in optical grades so that these require no further purification. These advantages are good enough to develop the resolution method of the present invention into industrial process with a great deal ofeconomical merits and enable to have the mixture of (+)-cisand (+)-trans-chrysanthemic acids first industrially available.  
  The optically active organic amine having the formula (I) is conveniently prepared in the following manners: Friedel-Crafts acylation of benzene gives the corresponding benzyl-phenylketone, which is converted to the amine by the Leuckart reaction. The racemic amine thus obtained is resolved with aspartic acid to afford the optically active amine.  
  Examples of the amine used in the present invention include (+)-a-phenyl-B-p-tolyl-ethylamine. (+)-a-p-tolyl-B-phenyl-ethylamine and (+)-a-phenyl-B-phenyl-ethylamine.  
  It becomes effective to carry out the optical resolution of the mixture comprising.(i)-cisand (i)-transchrysanthemic acids when the content of :(il-cischrysanthemic acid is not less than 3%by weight and. as a rule, it is effectively carried out when the content of (i)-cis-chrysanthemic acid is 10 to 30% by weight and a suitable organic solvent such as. for example. an alcohol such as methanol. ethanol, propanol or isopropanol; a ketone such as acetone or methyl ethyl ketone;  
 an ether such as tetrahydrofuran or dioxane. dimethyl-&#39; formamide. dimethylsulfoxide, a mixture thereof. or an aqueous mixture thereof.  
  In carrying out the present process. (:)-cisand (i)- trans-chrysanthemic acids and the aforesaid amine are dissolved respectively in the aforesaid solvent according to the conventional procedure. for example. by heating, and the resulting solutions are mixed each other. The crystallization of the amine salts may be conducted by the conventional manner. for example. by utilizing the differences of the dissolving temperature and the crystallization temperature, or by using a solvent, which is different fromrthe solvent used for dissolving them and which hardly dissolves the amine salts. The aforesaid amine may be used in an almost equimolar amount to the (i)-cis-, (id-transchrysanthemic acids. The concentration of the (i)-cis-,  
 (i)-trans-chrysanthemic acids in the solvent is l to 20% by weight, preferably about 10% by weight. The resulting amine salts may be decomposed according to the conventional procedure, for example. by adding an aqueous alkaline solution.  
 &#39; The process of the present invention is illustrated below with reference to examples. which are only illustrative. but not limitative.  
 r EXAMPLE 1f Into a solution of.12.0 gofa 1 1:89 mixture of (i)cisand (i)-trans-chrysanthemic acids in 97ml of 85% methanol was dropped at 45 to 50C a solution of 11.31 g of (+)-a phenyl-l3-p-tolyl-ethylamine in 33 ml of 85% methanol, and a (+)-amine salt of (+)-trans acid was seeded into the mixed solution. Subsequently. the solution was cooled to 20C over a period of about 2 hours. while stirring the&#39;system vigorously. and then stirred for 5 hours to deposit crystals of the resulting amine salt/The deposited crystals were recovered by filtration and dried. and then the salt was decomposed with NaOH. Thereafter, free (+)-amine was removed by extraction with toluene. and the aqueous layer was acidified. extracted with petroleum benzine and then concentrated to obtain optically active chrysanthemic acid.  
  Yield 67% vs.  
 (+l-chrysanthemic acid (is/trans ratio 9.7/90.3  
 Optical purity 7271 In the above. the recovered salt was purified according to ordinary recrystallization and then subjected to the -&#39;above-men&#39;tioned isolation operation. whereby pure optically active=chrysanthemic acid could-be easily obtained.  
 &#39; i EXAMPLE 2 12.0 Grams of-a 15.285 mixture of (i)-cisand (i)- trans-chrysanthemic acids was treated in the same manner as in: Example 1. using 11.31 g of the same (&#39;-lr;)--amineas in Example 1 and a total of 122 ml of 85% methanol. tolobtain optically active chrysanthemic -acid. &#34;i 72% vs.  
  (+)-chrysanthemic acid (is/trans ratio 115/875 v 1 1 +2(1.73 (cHcn) Optical purity 78% Y EXAMPLE 3 12:0 Grams of a&#39; :80 mixture of (i)-cisand (i)- trans chrysanthemic acids was treated in the same manner as in Example 1, using 11.31 g of the same amine as in Example 1 and a total of 122 ml of 85% methanol, to obtain optically .active chrysanthemic .acid.  
 Yield (+lchrysanthemic acid .Cis/trans ratio ISM/ 82.0 1 1 +31 144 (CHCl Optical purity 84.29;  
  EXAMPLE 4 12.0 Grams of a 25:75 mixture of (i)-cisand (i)- trans-chrysanthemic acids was treated in the same manner as in&#39;Example ,1, using 11.31 g of the same (+)-amine as in Example 1 and a total of 122 ml of 85% methanol. to obtain optically active chrysanthemic acid.  
 Yield 68.2% \s.  
 . (+)-chrysanthemic acid Cis/trans ratio 25.9/74.l [01],. +35.86(CHC1;,) Optical purity 84. We  
 EXAMPLE 5 12.0 Grams of a 5:95 mixture of (i)-cisand (i)- trans-chrysanthemic acids was treated in the same manner as in Example 1. using 11.31 g of the same (+)-amine as in Example 1 and a total of 108.5 ml of 85% methanol to obtain optically active chrysanthemic acid.  
 Yield 96% vs.  
  (+l-chrysanthemic acid (is/trans ratio 17/973 [01],, +9.18 (CHCl Optical purity 32.3%  
 EXAMPLE 6 12.0 Grams of a 20:80 mixture of (i)-cisand (i)- trans-chrysanthemic acids was. treated in the same manner as in Example 1. using 11.31 g of the same (+)-amine as in Example 1 and a total of 1 11 ml of 85% methanol. The deposited crystals were washed with cold %methanol to obtain after the working-up described in Example 1 optically active chrysanthemic acid.  
 Yield 66% vs.  
  (+)-chrysanthemic acid (is/trans ratio l7.3/82.7 [01],, +36.()5 (CHCl Optical purity 3. A process according to claim 1, wherein the dextrorotatory organic amine is selected from the group consisting of (+)-a-phenyl-B-p-tolyl-ethylamine, (+)-a-p-tolyl-B-phenyl-ethylamine and (+)-a-phenyl-B-phenyl-ethylamine.  
 4. The mixture of (+)-cisand (+)-transchrysanthemic acids obtained according to claim 2.