Patent GB-1233221-A (GB)
IPC: A23L27/20
Filed: 1968-05-23
Abstract: 1,233,221. α.#-Unsaturated carbonyl compounds. R. FIRMENICH, G. FIRMENICH, R. E. FIRMENICH, and F. H. FIRMENICH, [trading as FIRMENICH & CIE.]. 23 May, 1968 [26 May, 1967; 29 Sept., 1967; 10 May, 1968], No. 24656/68. Heading C2C. Olefinically α,#-unsaturated carbonyl compounds of general formula containing at least 7 carbon atoms and at least one group having the following carbon skeleton are prepared by heating in the presence of a condensing agent either (i) a butadienyl ether of the formula wherein Y = linear or branched C 1-4  alkyl, benzyl, p-nitrobenzyl or furfuryl, R 1 , R 2 , R 3  and R 4 = H, C 1-6  linear or branched alkyl; or (ii) a substance capable of generating such a butadienyl ether under the condensation conditions with (iii) an allyl alcohol, containing at least three carbon atoms and at least four carbon atoms less than the required end product, of the general formula wherein R 5 , R 6 , R 7  and R 8  = H or (a) C 1-8  linear or branched alkyl; or (b) C 1-8  linear or branched olefinically unsaturated hydrocarbon containing at most two double bonds; or (c) R 5 , R 6  and R 7  or R 8  have the meaning defined in (a) or (b) whereas R 7  or R 8  represent ethyl carrying on the terminal carbon atom an unsubstituted or a mono- or di-methyl substituted 5- or 6-membered olefinically unsaturated cycloaliphatic group containing at most 2 double bonds one of which is α to said terminal carbon atom, or ethyl carrying on the terminal carbon atom an unsubstituted or mono- or di-methyl substituted olefinically unsaturated bridged cycloaliphatic group containing a double bond α to the terminal carbon, or ethyl carrying on the terminal carbon atom or 2- or 3-furyl, or 2- or 3-thienyl group or wherein (d) two of the radicals represented by R 5 , R 6 , R 7  and R 8  can be linked to each other, except R 5  to R 6 , to form a 5- or 6-membered olefinically unsaturated cycloaliphatic ring which contains at most two double bonds and which can carry C 1-3  alkyl or alkenyl, or a 6- membered olefinically unsaturated bridged cycloaliphatic ring containing 1 double bond and which can carry 2 methyl groups, or a furan or thiophene ring which can carry a methyl group. As compounds capable of generating I under the conditions of the reaction may be used. Reduction of the carbonyl function by means of LiAlH, results in the corresponding allyl alcohol. 2,7,11-Trimethyl-2,6,10- dodecatrienal, 2 - methyl - 2,6 - octadienal, 2,6- dimefhyl - 2,6 - octadienal, 2,6,10 - triemthyl- 2,6,10 - dodecatrienal, 5 - (2 - furyl) - 2 - pentenal 2 - methyl - 5 - (3 - -furyl) - 2 - pentenal, 2 - methyl. 4 - (2 - thenyl) - 2 - butenal 2,7,11 - trimethyl- 2,6,10 - dodecatrianol, 2 - methyl - 2,6 - octadienol 2,6,10 - trimethyl - 2,6,10 - dodecatrienol, 2- methyl - 5 - (2 - furyl) - 2 - pentenol and 2- methyl - 5 - (3 - furyl) - 2 - pentenol are claimed per se and α - and # - sinensals, 2 - methyl - 5- (2 - -furyl) - 2 - pentenal, 2 - methyl - 5 - (3 - -furyl)- 2 - pentenal, 9 - (3 - -furyl) - 2,6 - dimethyl - 2,6- nonadienal, # - (4,8 - dimethyl - 3,7 - nonadienyl) furan, 2 - methyl - 4 - (8 - α - pinenyl) - 2 - butenal, 2 - methyl - 4 - (1 - methyl - 4 - isopropenyl - 1 - cyclohexen - 6 - yl) - 2 - butenal and 2,6 - dimethyl - 2,6 - octadienal are prepared. The dinitrophenylhydrazones of 2,7,11-trimethyl- 2,6,10 - dodecatrien - 1 - al - 2 - methyl - 2,6- octadien - 1 - al, 2,6 - dimethyl - 2,6 - octadienal, 2 - methyl - 5 - (2 - furyl) - 2 - pentenal and the semicarbazones of 2,6-dimethyl-2,6-octadienal and 2-methyl-5-(2-furyl)-2-pentenal are also isolated. The compounds of the invention are useful in the manufacture of perfumes and perfumed products and as flavouring agents for foodstuffs and beverages.