- Preparation method of pranlukast intermediate
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The invention relates to the field of medicine synthesis, and particularly discloses a preparation method of a pranlukast intermediate. The preparation method of the pranlukast intermediate comprisesthe following steps: taking 4-phenylbutoxy benzoic acid and 3-amino-2-hydroxyacetophenone as raw materials, adding a phosphotungstic acid catalyst into a reaction system, and carrying out amidation reaction to obtain a target product 3-[4-(4-phenylbutoxy)benzoylamino]-2-hydroxyacetophenone. The preparation method provided by the invention has the advantage of environmental protection on the premise of ensuring the yield and purity of the target product.
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Paragraph 0032-0042
(2020/12/08)
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- Preparation method of pranlukast intermediate
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The invention relates to a preparation method of a pranlukast intermediate. The method is carried out specifically according to the steps of: a. reacting a compound 2 with a compound 3 under the catalysis of alkali to generate a compound 4; b. under the c
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Paragraph 0043-0046
(2019/11/19)
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- New preparation method of Pranlukast
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The invention provides a new preparation method of drug Pranlukast for treating asthma. The new preparation method includes the specific steps that with 2-aminophenol-4-sulfonic acid as a starting material, a key intermediate 3-amino-2-hydroxyacetophenone is prepared by means of acylation, Fries rearrangement and deprotection, then reacts with 4-(phenylbutoxy)benzoic acid, and then is subjected to condensation with ethyl 1H-tetrazole-5-acetate, and finally preparation is achieved through ring closing under the acidic condition. Compared with the prior art, the raw material used for the new preparation method is low in price and easy to obtain, industrialization of a process can be achieved easily, and the obtained final product is high in purity; and no dangerous process exists, equipment is simple, and the route is novel.
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Paragraph 0019
(2017/05/27)
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- METHODS FOR PREPARING AMIDE DERIVATIVES
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The present invention provides a novel method for preparing an amide derivative. The method of the present invention enables to economically prepare various amide derivatives containing pranlukart by reacting a carboxylic acid derivative 5 and an amine derivative through a brief procedure compared with a conventional technology, and permits to obtain a final product at a high yield rate because it is feasible to eliminate by-products after termination of reactions. Accordingly, the present method is to be quite suitable for massive production.
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Page/Page column 29
(2010/04/03)
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- Process for the preparation of benzopyran compounds
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PCT No. PCT/EP97/04328 Sec. 371 Date Feb. 8, 1999 Sec. 102(e) Date Feb. 8, 1999 PCT Filed Aug. 5, 1997 PCT Pub. No. WO98/06718 PCT Pub. Date Feb. 19, 1998A process for preparing certain substituted benzopyran compounds is disclosed.
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- Process for preparing aromatic amide compound
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3-?4-(4-Phenyl-1-butoxy)benzoyl!amino-2-hydroxyacetophenone is prepared by reacting a benzoate ester with a halobutylbenzene in the presence of a basic compound and an aprotic polar compound in an aromatic hydrocarbon solvent to obtain a corresponding eth
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- Process for preparing tetrazol-5-yl substituted benzopyran compounds
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A process for preparing substituted benzopyran derivatives which comprises a final step cyclisation of the corresponding open-chain intermediates.
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