| 摘要 |
The invention comprises the phosphorus compounds triphenyl - [3,7 - dimethyl - 7 - methoxyoctadien - (2,4) - yl] - phosphonium halide, and triphenyl - [3,7 - dimethyl - 7 - methoxy - octen-(2)-yl-phosphonium halide on the one hand, and their conversion into spirilloxanthin, and also 1,11-dimethoxy-1,112,21-tetrahydro-lycopene as a novel intermediate in the latter conversion. The phosphonium halides are prepared by treating 6-methyl-heptan(5)one(2) with methanol in acidic medium to give 6 - methoxy - 6 - methyl-heptanone(2). To prepare the first-named phosphonium halide, the heptanone(2) is reacted with halo-acetic acid ethyl ester and Zn and the resulting 3-hydroxy-3,7-dimethyl-7-methoxy -octanoic - (1) - acid ethyl ester dehydrated to 3, 7 - dimethyl - 7 - methoxy - octanoic -(1)-acid ethyl ester. By reaction with N-bromo, succinimide followed by dehydrobromination this is converted to 3,7-dimethyl-7-methoxy-octadien-(2,4)-oic-(1) acid ethyl ester which is then reduced to 3,7-dimethyl-7-methoxy octadien-(2,4)-ol(1). The novel phosphonium halide is then prepared by reaction with triphenyl phosphonium halide. By reaction with crocetin dialdehyde and sodium methoxide, this halide is converted to spirilloxanthin. To prepare the second-named phosphonium halide, the heptanone(2) prepared as above is condensed with sodium acetylide, giving 3-hydroxy - 3,7 - dimethyl - 7 - methoxy - octyne-(1), which is hydrogenated catalytically to 3-hydroxy-3,7-dimethyl-7-methoxy-octene(1); this is reacted with triphenyl phosphonium halide to form triphenyl-[3,7-dimethyl-7-methoxy - octen(2)-yl]phosphonium halide, i.e. the second above-named novel phosphorus compound. In the case of this compound, spirilloxanthin is prepared by reaction of the compound with crocetin dialdehyde as before, but here, the third-named novel intermediate, 1,11-dimethoxy-1,11, 2,21-tetrahydrolycopene is first formed. This is reacted with N-bromo succinimide, and then dehydrobrominated to give spirilloxanthin. Two examples are given, of the alternative stepwise preparations of spirilloxanthin; this substance is stated to be useful as a colouring agent for foodstuffs. Specifications 999,252, 999,253, 999,254 and 999,255 are referred to. |
