The invention relates to a preparation method of
tiamulin base. The preparation method includes: filtering pleuromulin
fermentation broth,
drying mycelium, performing leaching by using
methanol as
solvent, using
acetone to extract leach liquor after vacuum concentration, concentrating extract, transferring concentrate into a synthetic reactor, adding paratoluensulfonyl
chloride, allowing for synthetic reaction at pH of 11-12 and
reaction temperature of 20-30 DEG C, allowing for standing and layering after complete reaction, adding
tetrabutylammonium bromide and diethylaminoethyl mercaptide into
ketone phase respectively , allowing for full reaction at pH of 9-10 and the
reaction temperature of 50-60 DEG C, adding water for extraction, discarding aqueous phase, filtering the
ketone phase, and reducing the original volume to 60-70% by vacuum concentration to obtain
tiamulin base. The original process is improved, the salifying and
crystallization process is omitted, the
tiamulin base is used to produce preparations directly, and accordingly equipment
investment cost and production cost are lowered, product quality is improved, and the content of tiamulin base reaches 80-90%. Organic solvents used in the preparation method are recyclable, environmental
pollution is reduced, and the preparation method has promising development prospect.