Isoxepac is a non-steroidal anti-inflammatory with analgesic and antipyretic activity. It is more slowly absorbed and eliminated in the rat and rabbit after oral dosing than in the dog, rhesus monkey and man.It can be used to treat allergic rhinitis, urticaria, and skin diseases with itching symptoms.
Isoxic acid is an important intermediate in the synthesis of the new preferred anti-allergic drug, olopatadine hydrochloride, preparation method of isoxepac:
(1) condensation: prepare p-hydroxyphenylaceticacid 8-12 part, phthalide 6-12 part, sodium methylate 8-12 part by weight; Dissolve with DMAC and to add said sodium methylate behind said p-hydroxyphenylaceticacid and the phthalide; Be that 0.1-10Pa is heated to 80-170 ℃ of reaction 3-10h at pressure then; Regulate the pH value to 1-5,4-(2-carboxyl benzyloxy) toluylic acid is separated out in crystallization;
(2) cyclization: with Glacial acetic acid min. 99.5 dissolving step (1) gained 4-(2-carboxyl benzyloxy) toluylic acid, adding 3-52 weight part polyphosphoric acid again, is that 0.1-10Pa is heated to 30-100 ℃ of reaction 3-12h at pressure, and crystallisation by cooling gets the Isoxepac bullion then;
(3) purify: behind the said Isoxepac bullion of acetic acid ethyl dissolution, refining decolouring gets the Isoxepac product.
https://patents.google.com/patent/CN102838582A/en
