| 摘要 |
The invention comprises cis-1,3-dihydroxy-2-nitro-octadec-4-ene in the form of its threo and erythro isomers and comprises also a process whereby threo and erythro isomers of 1,3-dihydroxy-2-amino-octades-4-ene are prepared by separating the corresponding 1,3-dihydroxy-2-nitro-alk-4-yne into its threo and erythro isomers by fractional crystallization, reducing the nitro group in the threo or erythro isomer with a metal in the presence of an acid which forms a salt with the metal, e.g. zinc and hydrochloric acid, and reducing the triple bond of the threo or erythro 1,3-dihydroxy-2-amino-alk-4-yne either with hydrogen and a catalyst, e.g. a Lindlar catalyst or a quinoline poisoned palladium catalyst, in which case a cis compound is obtained, or with an alkali metal and alcohol or a dimetal hydride, e.g. LiAlH4, in which case a trans compound is obtained. Alternatively, the nitro group and the triple bond may be reduced in one operation suitably by the use of lithium aluminium hydride or by hydrogenation in the presence of a catalyst to give a trans or a cis compound, respectively. If the latter process of reduction by hydrogenation in the presence of a catalyst is stopped after the uptake of 1 molecular equivalent of hydrogen, the intermediate cis-1,3-dihydroxy-2-nitro-alk-4-enes, which are claimed per se, are obtained.
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