GB556665A - - Google Patents

Abstract

556,665. De-alkylation of phenol ethers. LILLY & CO., E., and CORSE, J. April 14, 1942, No. 4923. [Class 2 (iii)] Compounds of the general formulae where R & R 2 are alkyl radicals having less than 5 carbon atoms, and R 2 and R 3 are alkyl or alkenyl radicals having less than 5 carbon atoms, are dealkylated by heating to a temperature above e 190‹C. with an alkali hydroxide dissolved in a solvent consisting of either a water soluble glycol having less than 5 carbon atoms or a water soluble polyalkylene glycol having less than 10 carbon atoms. Glycols mentioned include ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, and triethylene glycol. A clear or almost clear solution indicates the finish of the reaction. In examples (1) p - - p<SP>1</SP> dimethoxy - α - - # - diethyl stilbene is treated with potassium hydroxide dissolved in diethylene glycol at 215‹C. - 235‹C. for 3 hours. Acidification of the products yields the desired p - pl - dihydroxy - diethyl stilbene. (2) As in example (1) except that dipropylene glycol is used as the solvent. (3) As in example (1) but using as the starting material α - # - bis - (p - methoxyphenyl) - α - # - diethyl ethane. The corresponding dihydroxy compound is obtained. (4) As in example (1) using as the parent material p - p<SP>1</SP> - dimethoxy - cc - methyl - # - ethyl stilbene. (5) As in example (1) using as parent material p - p<SP>1</SP> - dimethoxy - α-#-di - n - butyl stilbene. (6) As in example (1) using as the parent material p - p<SP>1</SP> - dimethoxy - α - # - diallyl stilbene.