The invention relates to a preparation method for
progestin. 4-
androstenedione is used as a
raw material. The preparation method comprises the following steps: A, etherate is synthetized, wherein the 4-
androstenedione and
triethyl orthoformate perform an
acid catalyzed reaction in organic solvents of
dichloromethane, low-carbon
alcohol and the like to obtain the etherate 3-ethoxy-
androstane-3, 5-diolefin-17-
ketone; B, a nitro substance is synthetized, wherein the etherate in the organic solvents and
nitroethane perform 17-bit addition under the
catalysis of
ethylenediamine to obtain the nitro substance 3-ethoxy-20-nitro-
pregnane-3, 5, 17 (20)-triene; and C, the
progestin is synthetized, wherein the nitro substance is reduced by
zinc powder in organic solvents of acetic acids, low-carbon
alcohol and the like,
acid hydrolysis is performed, so that semi-finished products of the
progestin are obtained, the semi-finished products of the progestin are decolored and refined by
alcohol and
activated carbon to obtain the progestin, the content of HPLC is more than 99.5%, the
melting point is 128-131 DEG C, and the total yield of synthetized weight is 83-87%. When the method disclosed by the invention is used for producing the progestin, the yield is high, the degree of purity is good, the quality is stable, the
solvent recovering rate is high, and the method is economic and environment-friendly.