| 摘要 |
The invention comprises compounds of the formulae <FORM:0834378/IV (b)/1> or <FORM:0834378/IV (b)/2> wherein R1 represents an alkyl group containing 1-5 carbon atoms, R2 represents the methyl group containing 1-5 carbon atoms, R2 represents the methyl group, or R1 and R2 together represent the pentane-ethylene radical, R3 represents an acyl group and R30 is an acyl radical; and a process for the manufacture of unsaturated ketones which process comprises treating an ester of the formula <FORM:0834378/IV (b)/3> or <FORM:0834378/IV (b)/4> (where R1, R2 and R3 are as above defined) or a derivative thereof containing a methyl group as a substituent on the fourth, fifth or sixth carbon atom (counting from the acetylenic end), with an acidic agent in the presence of a metal or metal compound of Group IA of the Periodic System and hydrolysing the reaction product in an alkaline medium in the presence of a lower aliphatic acyclic or cyclic ketone of the general formula <FORM:0834378/IV (b)/5> (wherein X is a hydrogen atom or a lower aliphatic group and Y is a lower aliphatic group or X and Y together represent a lower aliphatic divalent group as shown by the broken line) to give a ketone of the general formula <FORM:0834378/IV (b)/6> (wherein R1, R2, X and Y are as above defined), or a derivative thereof containing a methyl group as a substituent on the fifth, sixth or seventh carbon atom (counting from the carbon atom adjacent to the keto group). As acidic agents there may be used acetic propionic or butyric acids, sulphuric and phosphoric acid. As catalysts there may be used cupric oxide or the acetates, carbonates, oxalates, nitrates and sulphates of copper and silver. Examples describe the preparation of pseudoionone, methyl - pseudoionone, allyl - pseudoionone, n-methyl - isomethyl - pseudoionone and methyl-pseudoionone. |
