GB651653A - Improvements in or relating to marihuana-like compounds - Google Patents

Abstract

Compounds of the formula <FORM:0651653/IV (b)/1> where R is an alkyl group of 1-5 carbon atoms, one of R1 and R2 is hydrogen and the other is an alkyl group of 1-5 carbon atoms, and R3 is an alkyl group of 1-8 carbon atoms, are obtained by the methods of the parent Specification, i.e. cleaving the ether groups of a 3 : 5-dimethoxy -1-(R3-CHR2-CRR1)-benzene and condensing the resulting substituted resorcinol (1) with pulegone, or (2) with an alkyl 5-methylcyclohexanone-2-carboxylate and treating the resulting dibenzopyrone with an alkyl magnesium halide. The hydroxyl group in the products may be acylated or alkylated, e.g. to form the acetate or methyl ether, and the double bond in the left-hand ring may be reduced. The substituted resorcinol dimethyl ethers may be obtained as follows: in the case where R1 is hydrogen, 3 : 5-dimethoxy-benzamide is reacted with a sec.-alkyl magnesium halide to give a sec. - alkyl - (3 : 5 - dimethoxy - phenyl) - ketone, which is then reduced to the carbinol, dehydrated with sulphuric acid and catalytically hydrogenated; thus, 2-(3 : 5-dimethoxyphenyl)-3-methyl-pentane, 2-(3 : 5-dimethoxyphenyl)-3-methyl-octane and 3-(3 : 5-dimethoxyphenyl)-2-methyl-pentane are prepared. In the case where R1 is alkyl, the same treatment is applied to an alkyl-(3 : 5-dimethoxy-a a -dialkyl-benzyl)-ketone which can be obtained as follows: 3:5-dimethoxy-benzoic acid is converted into the acid chloride with thionyl chloride and heated with ethanol to give the ethyl ester; this is treated with hydrazine to form the acid hydrazide and acylated with p-toluene-sulphonyl chloride; the resulting sulphonyl-hydrazide is decomposed with glycerol and potassium carbonate yielding 3 : 5-dimethoxybenzaldehyde, which is then reduced to 3 : 5-dimethoxy-benzyl alcohol; this is converted into the chloride with thionyl chloride and then into the cyanide, which is alkylated to give the 3 : 5-dimethoxy-a a -dialkyl-benzyl cyanide; reaction of this with a p Grignard reagent yields the desired ketone. 2-Methyl-2-(3 : 5-dimethoxyphenyl)-3-pentanone and 2-methyl-2-(3 : 5-dimethoxy-phenyl)-3-octanone are thus prepared, and the keto group converted into a methylene group as described above. Specifications 558,554 and 564,827 are referred to.