Improvements in the production of compounds of the beta-cyclogeranylidene series
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...
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Main Authors | , |
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Format | Patent |
Language | English |
Published |
13.09.1961
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Subjects | |
Online Access | Get full text |
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Summary: | 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. |
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Bibliography: | Application Number: GB19590008735 |