Diarylmethylenes

#This invention relates to a new class of chemical compounds having utility as antilittering agents. The novel compounds are diarylmethylenyl cyclohexane carbinols and esters thereof and are typified by compounds having the following molecular structure: ##STR1## wherein R.sub.1 is hydrogen or --COR wherein R is lower alkyl of from 1 to 5 carbon atoms such as methyl, ethyl, propyl, isopropyl, butyl and the like; R.sub.2 is hydrogen, a lower alkyl group of from 1-5 carbon atoms or a lower alkynyl group of from 2-5 carbon atoms such as ethynyl, propynyl, butynyl and the like; R.sub.3 and R.sub.4 are hydrogen, a lower alkyl group of from 1-5 carbon atoms, a lower alkoxy group of from 1-5 carbon atoms such as methoxy, ethoxy, propoxy, isopropoxy, butoxy and the like or a lower alkanoyloxy group of from 2-5 carbon atoms such as acetoxy, propionyloxy and the like. Preferred among the compounds represented above are those wherein R is lower alkyl and R.sub.3 and R.sub.4 are each hydrogen, although those compounds wherein R.sub.3 and R.sub.4 are lower alkoxy and lower alkanoyloxy also show good activity. The most preferred compound of the present invention is 1-(diphenylmethylenyl)-2-methyl-3-ethyl-4 -acetoxy-cyclohexane.

#The novel diarylmethylenyl cyclohexane carbinol esters and derivatives of the present invention can be prepared by reacting an appropriately substituted, protected cyclohexanone with a Grignard reagent carrying the desired aryl moiety of the final compound. Suitable protecting groups for the cyclohexanone include ketals such as the cyclic ethylene ketal and thioketals such as the cyclic ethylene thioketal. The resulting condensation product is then dehydrated, preferably in a strong acid catalyzing system, to effect formation of the methylene bridge. Suitable acid catalysts include p-toluenesulfonic acid, hydrochloric acid, sulfuric acid and the like. The acid-catalyzed reaction has no stereochemical affect on the alkyl groups. The ketone protecting group is then removed and the cyclohexanone compound which forms is a useful intermediate which also possesses some antilittering activity. The preferred reagent for regenerating the ketone from the protecting group is a mixture of mercuric chloride and cadmium carbonate. The cyclohexanone intermediate is then reduced to the hydroxy compound with an appropriate reducting agent such as a complex metal hydride. Suitable complex metal hydrides are lithium aluminum hydride, sodium borohydride and the like. The final step is an esterification process whereby the hydroxy group is converted to the appropriate ester function using standard esterification techniques.

#The thioketals which are used as the starting materials in the preparation of the novel diamylmethylene cyclohexane carbinol esters are themselves novel compounds as are all of the compounds obtained during each step of the reaction sequence. The starting materials may be prepared in accordance with the procedures set forth in the Examples hereinafter presented.

#The following examples are given to illustrate specific and preferred embodiments of the present invention:

#To a stirred suspension of 1.0 g. of lithium aluminum hydride in 30 ml. of tetrahydrofuran is added, portionwise, a total of 2.0 g. of 1-diphenylmethylenyl-2-methyl-3-ethyl-4-ketocyclohexane. The resulting mixture is stirred at 25.degree. C. for 40 minutes, after which it is poured into a cold stirred mixture of 10 ml. of 20% aqueous sodium hydroxide, 10 ml. of saturated brine and 100 ml. of ethyl ether. The hydrolysis mixture is stirred at 25.degree. C. for 40 minutes, filtered to remove inorganic solids and the filtrate layers are separated. The ether phase is washed with water, dried over magnesium sulfate and upon evaporation 2.0 g. of 1-diphenylmethylenyl-2-methyl-3-ethyl-4-hydroxycyclohexane are obtained as a viscous oil. The crude carbinol is dissolved in a mixture of 25 ml. of pyridine and 3 ml. of acetic anhydride and the resulting solution is maintained at 90.degree. C. for 5 hours. The solution is then cooled to 15.degree. C., diluted with 100 ml. of water and extracted with 30 ml. of hexane. The hexane solution is successively washed with cold dilute hydrochloric acid, water and sodium bicarbonate, dried over magnesium sulfate and evaporated to an oily residue. The residue is chromatographed on neutral alumina, and the column is eluted with a 10% ether - 90% hexane solution. The eluates are combined and evaporated to yield 1.6 g. of crystalline material. Upon two recrystallizations from aqueous methanol 0.85 g. of the 2,3-cis-3,4-cis isomer of 1-diphenylmethylenyl-2-methyl-3-ethyl-4-acetoxycyclohexane, are obtained as fine white prisms, m.p. 91.degree.-92.degree. C.

#.lambda..lambda.max: 3.28, 3.31, 5.75, 7.28, 8.08, 9.20-9.30, 14.30.mu.(CCl.sub.4)