| 摘要 |
All-trans C40-carotenoid are prepared by heating suspensions of 15,151-monocis C40-carotenoid compounds in an inert organic liquid e.g. pentanes, hexanes, cyclohexane, benzene, toluene, petroleum ethers and ethyl acetate. As the 15,151-monocis carotenoid compound there may be used lycopene, a -, b - and g -carotene and hydroxy and keto derivatives thereof. Examples describe the production of all-trans-b - carotene, all - trans - 3,4;31,41 - bisdehydro - b - carotene, all - trans - 3,4 - dehydro - b - carotene, all - trans - 4,41 - dihydroxy - b - carotene, and all-trans-lycopene. The starting compound 15,151-monocis lycopene is obtained by treating 2,7-dimethyl-octadiene-2,6-ine-4-diol-1,8 with MnO2 to produce 2,7-dimethyl-octadiene-2,6 - ine - 4 - dial - 1,8 which with ethanol yields 2,7 - dimethyl - octadiene - 2,6 - ine - 4 - tetraethyldiacetal - 1,8, which with ethyl vinyl ether yields 3,10-diethoxy-4,9-dimethyl-dodecadiene - 4,8 - ine - 6 - tetraethyldiacetal - 1,12 which by hydrolysis yields 4,9-dimethyl-dodecatetraene-(2,4,8,10)-ine-6-diol-1,12 which with ethanol yields 4,9 - dimethyl - dodecatetraene - (2,4,8,10) - tetraethyldiacetal-1,12, which with ethyl propenyl ether yields 3,14-diethoxy-(2,6,11,15)-tetramethylhexadecatetraene - (4,6,10,12) - ine - 8 - tetraethyldiacetal-1,16, which by hydrolysis yields 2,6,11,15 - tetramethyl - hexadecahexaene - (2,4,6,10,12,14) - ine - 8 - diol - 1,16, which with triphenyl - [3,7 - dimethyl - octadiene - 2,6 - ylidene-(1)] phosphine yields 15,151-dehydro-lycopene, which on hydrogenation yields the desired 15,151-monicis lycopene. The compound triphenyl - [3,7 - dimethyl - octadiene - 2,6 - ylidene - 1]-phosphine is obtained by treating 1-bromo-3,7-dimethyl-octadiene-2,6 with triphenyl phosphine to produce triphenyl-[3,7-dimethyl-octadiene - 2,6 - yl - 1] - phosphonium bromide which is subsequently treated with phenyl lithium. Specifications 788,266 and 790,614 are referred to.ALSO:All-trans C40-carotenoid compounds (see Group IV (b)) are useful as colouring materials for foodstuffs. Compounds exemplified are all-trans-b -carotene all-trans-3,4,31,41-bisdehydro-b - carotene, all - trans - 3,4 - dehydro - b - carotene, all - trans - 4,41 - dihydroxy - b - carotene and all-trans-lycopene. Specifications 788,266 and 790,614, [both in Group IV (b)], are referred to. |
