The invention discloses a synthetic method of an all-trans
vitamin A acid medicament. The method comprises the following steps of: (1) preparing an intermediate: adding a
solvent and 2-5
equivalent weight of alkali into 5-hydroxy-4-methyl-2-furanone, reacting at the temperature of 35-40 DEG C for 1-3 hours, undergoing a ring opening reaction, cooling to between 5 DEG C below zero and 0 DEG C below zero, dropwise adding 0.75-1.0
equivalent weight of a C15-triphenyl
phosphine salt solution slowly for reacting for 3-4 hours, heating to the
room temperature for reacting for 6-10 hours, adding 40L of
ice water, extracting with a mixed
solvent consisting of
ethyl acetate and
petroleum ether in the ratio of 1:4, combining organic phases, washing with water for 2-3 times, and
drying with
anhydrous sodium sulfate to obtain a mixture of a 11cis,13contra-
vitamin A acid and a 11contra,13contra-
vitamin A acid compound; and (2) isomerizing: dissolving a 11cis,13contra and 11contra,13contra-
vitamin A acid mixture
solid obtained in the step (1) with a
solvent, adding 0.1-20 percent by mole of
iodine, and stirring and reacting at the temperature of 25-35 DEG C for 25-48 hours to obtain the all-trans
vitamin A acid medicament. The synthetic method has the advantages of easiness for operating, high yield, low cost, high product content and capability of avoiding
pollution of
heavy metals.