| 摘要 |
The invention comprises as new products acetylenic esters of the general formula: <FORM:0774621/IV(b)/1> wherein R1 is a hydrogen atom or a straight or branched chain alkyl radical containing up to ten carbon atoms, R2 is a straight or branched chain alkyl radical containing up to ten carbon atoms and R3 is an isoprenoid or hydrogenated isoprenoid radical of the formula: <FORM:0774621/IV(b)/2> <FORM:0774621/IV(b)/3> in which n is 1, 2, or 3. The products may be converted by selective hydrogenation into olefinic esters of the general formula: <FORM:0774621/IV(b)/4> wherein R1, R2 and R3 are as defined above. The acetylenic esters may be obtained by reacting an acetylenic tertiary carbinol of the general formula C CH.C(R2)(R3)OH, wherein R2 and R3 are as defined above with an anhydride of the formula: <FORM:0774621/IV(b)/5> wherein R1 is a hydrogen atom or a straight or branched chain alkyl radical containing up to 10 carbon atoms (at least one R1 being such an alkyl radical), in the presence of an acidic esterification catalyst. The reaction may be carried out at ordinary temperatures and with a slight molar excess of the anhydride. Specified esterification catalysts are phosphoric acid and p-toluene sulphonic acid. The various stereoisomeric forms of the acetylenic alcohols may be used to form the stereoisomeric forms of the acetylenic esters. The selective hydrogenation to form the olefinic esters may be carried out by treating the acetylenic esters with approximately a molar equivalent of hydrogen in the presence of a hydrogenation catalyst, e.g. a lead-palladium catalyst, which selectively catalyses the reduction of an acetylenic bond preferentially to an olefinic bond. The hydrogenation is preferably effected by treating a solution of the acetylenic ester in an inert organic solvent with hydrogen in the presence of a lead-palladium hydrogenation catalyst and quinoline at ordinary temperature and under slightly super-atmospheric pressure until about one mol. of hydrogen has been taken up. Examples are given for the production of the racemic acetate, propionate, n-butyrate, isobutyrate, and formate of 3,7-dimethyl - octen - (6) - in - ol - 3 and of 3,7,11-trimethyl - dodecadien - (6,10) - in - (1) - ol - 3 from the alcohol and appropriate acid anhydride and for their conversion to the corresponding olefinic esters. The formate esters are obtained by adding formic acid to acetic anhydride, maintaining the temperature below 30 DEG C. by cooling until the evolution of heat has ceased, and then adding aqueous phosphoric acid and the acetylenic alcohol. An example is also given for the production of the acetate of racemic 3,7,11,15 - tetramethyl - hexadecin - 1-ol-(3) and the corresponding olefinic ester. The acetylenic ester products are stated to be useful in the making of perfumes and scented compositions. Specification 711,010 is referred to. |
