Improvements in the production of compounds of the beta-cyclogeranylidene series

• Main Authors: SARNECKI WILHELM, POMMER HORST
• Format: Patent
• Language: English
• Published: 13.09.1961
• Subjects: ACYCLIC OR CARBOCYCLIC COMPOUNDS; CHEMISTRY; FOODS OR FOODSTUFFS; FOODS, FOODSTUFFS, OR NON-ALCOHOLIC BEVERAGES, NOT COVERED BYSUBCLASSES A23B - A23J; HUMAN NECESSITIES; METALLURGY; ORGANIC CHEMISTRY; PRESERVATION OF FOODS OR FOODSTUFFS, IN GENERAL; THEIR PREPARATION OR TREATMENT, e.g. COOKING, MODIFICATION OFNUTRITIVE QUALITIES, PHYSICAL TREATMENT; THEIR TREATMENT, NOT COVERED BY OTHER CLASSES

Compounds containing the beta - cyclogeranylidene compound e.g. vitamin A acid and esters, b -ionylidene ethanol, b -ionylidene acetic acid ethyl ester, axerophthene, homoisopreno-vitamin A acid, dehydro-b -carotene and vitamin A acetate are prepared by replacing the oxygen of an oxo group in an oxo compound by the group <FORM:0877351/IV (b)/1> wherein n is 0, 1, 2, 3 or 4 and R is H or CH3 by combining the alcohol <FORM:0877351/IV (b)/2> with a triarylphosphine and a proton donor, for example by adding the hydrogen acid salt of the triaryl phosphine R3PH.X wherein R is an aromatic radical and X is an anion, and after adding a proton acceptor such as an inorganic or organic base or an organo-metallic compound, condensing with the oxo compound. The oxo compound may suitably be an aldehyde or dialdehyde, a ketone, or a formic acid ester, many being specified. The reaction is preferably carried out in a polar solvent such as dimethyl formamide, acetonitrile, methanol, an acetic ester or nitrobenzene and at a temperature of -20 DEG C. to 30 DEG C. Trans-b -formylcrotonic acid used as an oxo reactant in the above processes is made by alkaline saponification of the diethylacetal of formyl-crotonic acid ethyl ester and deacetalisation of the product. Specifications 784,628 and 822,865 are referred to.