Patent GB-674059-A (GB)
Title: Improvements in or relating to the preparation of new unsaturated carbinols
Inventor: HEILBRON IAN MORRIS
IPC: C07C33/02
Filed: 1949-03-22
Abstract: The invention comprises compounds of the general formula <FORM:0674059/IV (b)/1> where R is either the group CH2=CH- or CH­C-, the compound of formula C9H14O having refractive index <FORM:0674059/IV (b)/2> = 1.5540, light absorption maxima 259, 268 and 279 mm , E1 per cent1 cm 2352,3040 and 2385, respectively, and e 32,500, 43,400 and 33,800, respectively, and the compound of formula C9H12O having refractive index <FORM:0674059/IV (b)/3> =1.5396,light absorption maximum 262 mm , E1 per cent1 cm. 1900 and e  26,000.  6 - Methylocta - 3 : 5 : 7 - trien - 2 - ol is prepared by treating 3-methylocta-1 : 4 : 6-trien-3-ol with an aqueous medium containing one or more inorganic and/or organic acids which do not have oxydizing properties, the pH of which medium is within the range of about 1-4.  6-Methylocta-3 : 5-dien-7-yn-2-ol is prepared by treating 3-methylocta-4 : 6-dien-1-yn-3-ol with an aqueous medium containing one or more inorganic and/or organic acids which do not have oxydizing properties, the pH of which medium is less than 4.  Acids mentioned are hydrochloric, sulphuric, phosphoric, oxalic and acetic acids or mixtures of two or more of these acids.  Acid-salt buffer mixtures may be used.  The starting material may be shaken directly with the aqueous medium or it may be dissolved first in a water-immiscible inert solvent such as benzene, ether or light petroleum.  Homogeneous conditions, produced by the addition of a water-miscible inert organic solvent, e.g. acetone, are preferred. The use of an inert atmosphere and an antioxidant such as hydroquinone or tocopherol are desirable.  In examples, 6 - methylocta - 3 : 5 : 7 - trien - 2 - ol is prepared by treating 3-methylocta-1 : 4 : 6-trien-3-ol with in (1) Clarke and Lubbs hydrochloric acid buffer pH 2; (2) dilute sulphuric acid; (4a) with pH 2 hydrochloric acid-potassium chloride buffer; (4b) the buffer employed in (4a), the starting material being dissolved in ether; (4c) N/10 hydrochloric acid, the starting material being dissolved in ether; (4d) the buffer employed in (4a), the reaction taking place in benzene; (4e) 28.5 per cent acetic acid; (6a) N/10 oxalic acid; (6b) N/10 phosphoric acid; (6c) N/10 potassium bisulphate, the starting material being dissolved in ether in (6a), (6b) and (6c); (7a) with hydrochloric acid, to produce a N/50 concentration, in aqueous dioxan; (7b) with hydrochloric acid to produce a N/100 concentration, in aqueous dioxan; (7c) with hydrochloric acid to produce N/50 concentration, in aqueous acetone.  6 - Methylocta - 3 : 5 : 7 - trien - 2 - ol is prepared by treating 3-methylocta-4 : 6-dien-1-yn-3-ol with, in examples (3) dilute sulphuric acid, in ether; (5a) N-hydrochloric acid, in benzene; (5b) N-oxalic acid solution, in ether; (8a) N/10 sulphuric acid, in aqueous dioxan; (8b) N/2 hydrochloric acid, in aqueous dioxan; (8c) N/2 potassium hydrogen sulphate, in aqueous acetone.  The products are obtained by either separating the solvent layer, or by extracting the reaction product with ether, washing and drying the solvent layer, evaporating the solvent and fractionating the residue.  A trace of hydroquinone is employed as antioxidant in most of the examples.  3-Methyl-4 : 6-dien-1-yn-3-ol may be prepared by the process of Specification 665,147.  3 - Methylocta - 1 : 4 : 6 - trien - 3 - ol may be prepared by hydrogenation of 3-methylocta-4 : 6-dien-1-yn-3-ol using a palladized calcium carbonate catalyst.