GB641026A - Improvements in or relating to the preparation of reduction products of n-phenyl-3, 5-diethyl-2-propyldihydropyridine - Google Patents

Abstract

N - phenyl - 3,5 - diethyl - 2 - propyldihydropyridine is hydrogenated at elevated temperatures, preferably 20 DEG to 150 DEG C., and pressures, preferably 3 to 100 atmospheres of hydrogen, and preferably in the presence of a hydrogenation catalyst such as Raney nickel, and metallic platinum and palladium. One, two or five mols. of hydrogen may be added by successively increasing the temperature, pressure and quantity of hydrogen used. In examples the dihydropyridine is hydrogenated in the presence of a Raney nickel catalyst and (1) and (2) ethanol at (1) 3 atmospheres, (2) 70 atmospheres and (3) 100 atmospheres of hydrogen with corresponding temperatures of room temperature, 100 DEG C. and 150 DEG C. and times of 3 hours, 10 hours and 20 hours and the following products isolated by fractionating at reduced pressure: (1) N-phenyl-3,5-diethyl-2-propyltetrahydropyridine; (2) N-phenyl-3,5-diethyl-2-propylpiperidine; and (3) N-cyclohexyl-3,5-diethyl-2-propylpiperidine. The dihydropyridine used as starting material is prepared by gradually adding aniline to commercial butyraldehyde dissolved in dilute acetic acid p solution at about 10 DEG C., refluxing for 5 hours, cooling, removing butyraldehyde and 2-ethylhexenal from the oil layer by steam distillation which is then dried and extracted in the cold with dilute hydrochloric acid and benzene to leave an oil layer from which the required product may be obtained by reduced pressure fractionation. N-Butylaniline and the reaction product of 2 mols. of butyraldehyde with 1 of aniline are obtained amongst the by-products.ALSO:N - phenyl - 3,5 - diethyl - 2 propyl - tetrahydropyridine, N-phenyl-3,5-diethyl-2-propylpiperidine and N-cyclohexyl-3,5-diethyl-2-propyl-piperidine are active insecticides, fungicides, bactericides and herbicides. Compositions containing 1 per cent of the above compounds are effective against cotton beetles and in fly sprays and when containing 10 p.p.m. are effective against mosquito larva. A kerosene composition containing about 5 per cent by weight of the compounds is effective in weed-killing.