A kind of preparation method to the hydroxyl thiobenzamide
Technical field
The present invention relates to a kind of preparation method, belong to chemical industry, medical technical field the hydroxyl thiobenzamide.
Technical background
To the hydroxyl thiobenzamide is the crucial starting raw material of synthetic gout therapertics Febuxostat, and at present, the following method of the general employing of its preparation: 4-hydroxybenzonitrile is in organic solvent, and certain pressure feeds hydrogen sulfide down and makes; Perhaps make as the reaction of sulphur source with thioacetamide; Or shown in patent documentation WO2005012273, in water system, 4-hydroxybenzonitrile feeds the stink damp precursor reactant under the catalysis of Sodium sulfhydrate, and route
Obviously, this method exists safety and pollution hidden troubles such as hydrogen sulfide toxicity damage, and production cost is high.For fear of the potential safety hazard of using hydrogen sulfide to bring; Patent documentation US20120078013 discloses a kind of improved preparation method; Be specially, 4-hydroxybenzonitrile is the sulphur source with the Sodium sulfhydrate in the mixed system of organic solvent (like N or DMSO 99.8MIN.) and water; Under the effect of ammonium chloride, make the hydroxyl thiobenzamide, its preparation route is following:
In addition, patent documentation US3700664 also reported adopt the thioformamide analogue, with above-mentioned similar compound method.But used a large amount of organic solvents among the above two improved preparing methods, caused cost to rise, and difficult solvent recovery.
Given this, we design the preparation method to the hydroxyl thiobenzamide who has invented a kind of efficient, environmental protection.
Summary of the invention
The technical problem that the present invention will solve is to overcome that the preparation method to the hydroxyl thiobenzamide pollutes greatly in the prior art, and low, the ropy problem of yield provides a kind of do not have hydrogen sulfide contamination, yield is high, quality is high new-type preparation method.
In order to solve the problems of the technologies described above, the invention provides following technical scheme:
