Patent GB-765516-A (GB)
Title: Novel unsaturated alcohols and esters and a process for preparation of same
Filed: 1955-01-28
Abstract: The invention comprises alcohols and esters of general formula: <FORM:0765516/IV(b)/1> in which R is a hydrogen atom or methyl group and X is a hydrogen atom or an organic acyl group.  They may be manufactured by converting 3.7-dimethyl-octen(1)-ol(3) or its 6-methyl homologue into 1 - halogeno - 3.7 - dimethyl-octene (2) or its 6-methyl homologue respectively by treatment with a halogenating agent, exchanging the 1-halogeno substituent for an organic acyloxy group by treatment with an alkali metal salt of an organic monocarboxylic acid and, if desired, hydrolysing the resulting 1-ester to give the 1-alcohol which may be reesterified.  The products may be used as odourimparting agents in the making of perfumes.  The preferred substances comprise esters in which X represents an acyl radical having not more than 8 carbon atoms, e.g. acetyl, propionyl, isobutanoyl, cyclohexyl carbonyl, cyclopentyl carboxy, benzoyl and toluoyl.  3.7-dimethylocten - (1) - ol (3) is a known compound and the other starting material 3.6.7-trimethyl-octen(1)-ol(3) may be obtained by acetylene addition to 5.6-dimethylheptanone-(2) and subsequent partial hydrogenation of the triple bond.  In the examples: (a) 3.7-dimethyl-octen-(1)-ol-3 is treated with hydrobromic acid to give 1 - bromo - 3.7 - dimethyl - octene - (2) which is treated with anhydrous potassium acetate and acetone to give 1-acetoxy-3.7-dimethyl - octene - (2); (b) 3.7 - dimethyl-octen - (1) - ol - (3) is heated with hydrochloric acid to give 1-chloro-3.7-dimethyl-octene-(2) which is treated with anhydrous potassium acetate and acetone to give 1-acetoxy-3.7-dimethyl - octene - (2); (c) the 1 - acetoxy - 3.7-dimethyl - octene - (2), obtained as in (a) or (b), is treated with ethyl alcohol and potassium hydroxide solution to give 3.7-dimethyl-octen-(2) - ol - (1); (d) the 3.7 - dimethyl - octen - 2-ol - (1), obtained as in (c) is treated with isobutyric acid anhydride and pyridine to give 1-isobutyroxy - 3.7 - dimethyl - octene - (2); (e) 3.7 - dimethyl - octen - (2) - ol - (1), formic acid and petroleum ether and heated to give 1-formyloxy - 3.7 - dimethyl - octene - (2); (f) 3.7 - dimethyl - octen - (2) - ol - (1) is treated with pyridine and benzoyl chloride to give 1-benzoyloxy - 3.7 - dimethyl - octene - (2); (g) 3.6.7 - trimethyl - octene - (1) - ol - (3) and hydrobromic-acid are reacted to give 1-bromo-3.6.7-trimethyl-octene-(2) which is treated with acetone and potassium acetate to give 1-acetoxy-3.6.7.-trimethyl - octene - (2); (h) 3.6.7 - trimethyl-octen - (1) - ol - (3) is treated with hydrochloric acid to give 1-chloro-3.6.7-trimethyl-octene-(2) which is treated with acetone and potassium acetate to give 1 - acetoxy - 3.6.7 - trimethyl-octene - (2); (j) 1 - acetoxy - 3.6.7 - trimethyl-octene-(2) is treated with potassium hydroxide solution to give 3.6.7-trimethyl-octen-(2)-ol-(1); (k) 3.6.7-trimethyl-octen-(2)-ol-(1) is treated with (i) formic acid, (ii) isobutyric acid anhydride, and (iii) benzoyl chloride to give 1-formyloxy - 3.6.7 - trimethyl - octen - (2), 1 - isobutyroxy - 3.6.7 - trimethyl - octen - (2), and 1-benzoyloxy - 3.6.7 - trimethyl - octene - (2) respectively.