CN104311544A

CN104311544A - Preparation method of benzoxazole derivative

Info

Publication number: CN104311544A
Application number: CN201410482468.9A
Authority: CN
Inventors: 陈芳军; 邓泽平; 李书耘
Original assignee: Hunan Huateng Pharmaceutical Co Ltd
Current assignee: Hunan Huateng Pharmaceutical Co Ltd
Priority date: 2014-09-22
Filing date: 2014-09-22
Publication date: 2015-01-28

Abstract

The invention discloses a preparation method of a benzoxazole derivative (1-(5-bromo[d] oxazole-2-yl) piperidine-4-yl) methylamine. A starting material 2-amino-4-bromophenol is subjected to cyclization, chlorination, nucleophilic substitution, aminolysis and reduction to obtain the target product. The compound is an important pharmaceutical intermediate.

Description

A kind of preparation method of benzoxazoles derivative

Technical field

The present invention relates to a kind of novel processing step of medicine intermediate, particularly a kind of preparation method of a kind of preparation method of (1-(5-bromobenzene is [d] oxazole-2-base also) piperidin-4-yl) methylamine.

Technical background

Compound (1-(5-bromobenzene is [d] oxazole-2-base also) piperidin-4-yl) methylamine, structural formula is:

This compound (1-(5-bromobenzene is [d] oxazole-2-base also) piperidin-4-yl) methylamine and relevant derivative have widespread use in pharmaceutical chemistry and organic synthesis.The synthesis of (1-(5-bromobenzene is [d] oxazole-2-base also) piperidin-4-yl) methylamine is comparatively difficult at present.Therefore, need exploitation raw material to be easy to get, easy to operate, reaction is easy to control, the synthetic method that overall yield is suitable.

Summary of the invention

The invention discloses the method that one prepares (1-(5-bromobenzene is [d] oxazole-2-base also) piperidin-4-yl) methylamine, with 2-amino-4-bromophenol for starting raw material, obtain target product 6 through the ring that reaches a standard, chloro, nucleophilic substitution, ammonia solution, reduction, synthetic route as shown in Figure 1.Synthesis step is as follows:

(1) with 2-amino-4-bromophenol for starting raw material, obtain 2 through ring closure reaction;

(2) carry out chlorination 2, obtain 3;

(3) carry out nucleophilic substitution reaction 3 and obtain 4;

(4) carry out ammonolysis reaction 4 and obtain target product 5,

(5) carry out reduction reaction 5 and obtain target product 6,

One preferred embodiment in, the reagent that described ring closure reaction prepares compound 2 used is selected from potassium ethyl xanthonate; The reagent that described chlorination prepares compound 3 used is selected from chlorine; The alkali that described nucleophilic substitution reaction prepares compound 4 used is selected from salt of wormwood; The reagent that described ammonolysis reaction prepares compound 5 used is selected from ammoniacal liquor; The reductive agent that described reduction reaction prepares compound 6 used is selected from lithium aluminium hydride.

One preferred embodiment in, the solvent that described ring closure reaction prepares compound 2 used is selected from pyridine; The solvent that described chlorination prepares compound 3 used is selected from trichloromethane; The solvent that described nucleophilic substitution reaction prepares compound 4 used is selected from DMF; The solvent that described ammonolysis reaction prepares compound 5 used is selected from tetrahydrofuran (THF); The solvent that described reduction reaction prepares compound 6 used is selected from tetrahydrofuran (THF).

One preferred embodiment in, described ring closure reaction prepares the reflux temperature that compound 2 temperature of reaction used is solvent; It is 0 DEG C ~ room temperature that described chlorination prepares compound 3 temperature used; Described nucleophilic substitution reaction prepares the reflux temperature that compound 4 temperature used is solvent; Described ammonolysis reaction prepare compound 5 used be room temperature; It is 0 DEG C ~ room temperature that described reduction reaction prepares compound 6 temperature used.

The present invention relates to the preparation method of one (1-(5-bromobenzene is [d] oxazole-2-base also) piperidin-4-yl) methylamine, there is no other Patents bibliographical informations at present.

Accompanying drawing explanation

Fig. 1 is the synthetic route chart of compound (1-(5-bromobenzene is [d] oxazole-2-base also) piperidin-4-yl) methylamine.

The present invention is further described by the following embodiment, and these descriptions are not be further limited content of the present invention.One skilled in the art will understand that the equivalent replacement that technical characteristic of the present invention is done, or improve accordingly, still belong within protection scope of the present invention.

Specific embodiment mode

Embodiment 1

(1) synthesis of 5-bromobenzene also [d] oxazole-2-mercaptan potassium

40g 2-amino-4-bromophenol is joined in 380ml pyridine, add 63g potassium ethyl xanthonate, reflux stirs 5 hours, the most of pyridine of concentrated removing, add dilute hydrochloric acid and ethyl acetate, separatory, collection organic phase, dry, concentrated, residuum upper prop is separated and obtains 51g 5-bromobenzene also [d] oxazole-2-mercaptan potassium.

(2) synthesis of the bromo-2-chlorobenzene of 5-also [d] oxazole

50g 5-bromobenzene also [d] oxazole-2-mercaptan potassium join in 1000ml chloroform, be cooled to 0 DEG C, pass into chlorine to saturated, keep 0 DEG C to stir 2 lab scales, then be warming up to room temperature continuation stirring 5 hours, concentrated, add water and ethyl acetate again, extraction separatory, collects organic phase, separatory, drying, concentrated, on residuum, silicagel column is separated to obtain the bromo-2-chlorobenzene of 36g 5-also [d] oxazole.

(3) synthesis of 1-(5-bromobenzene is [d] oxazole-2-base also) piperidines-4-carboxylic acid, ethyl ester

Bromo-for 35g 5-2-chlorobenzene also [d] oxazole join 160ml N, in dinethylformamide, then add 28g Anhydrous potassium carbonate, then add 26g 4-piperidine ethyl formate, be heated to return stirring 3 lab scale, be cooled to room temperature, add water and ethyl acetate, extraction separatory, collect organic phase, drying, concentrated, residuum is crossed post separation and is obtained 42g1-(5-bromobenzene is [d] oxazole-2-base also) piperidines-4-carboxylic acid, ethyl ester.

(4) synthesis of 1-(5-bromobenzene is [d] oxazole-2-base also) piperidines-4-methane amide

20g 1-(5-bromobenzene is [d] oxazole-2-base also) piperidines-4-carboxylic acid, ethyl ester is joined in 120ml tetrahydrofuran (THF), add 120ml ammoniacal liquor again, stirring at room temperature 18 hours, add extraction into ethyl acetate again, separatory, concentrated, on residuum, silicagel column is separated to obtain 14g 1-(5-bromobenzene is [d] oxazole-2-base also) piperidines-4-methane amide.

(5) synthesis of (1-(5-bromobenzene is [d] oxazole-2-base also) piperidin-4-yl) methylamine

12g 1-(5-bromobenzene is [d] oxazole-2-base also) piperidines-4-methane amide is joined in 160ml tetrahydrofuran (THF), be cooled to 0 DEG C, slowly add 5g Lithium Aluminium Hydride, naturally stirring at room temperature is risen to 7 hours, add 1M aqueous sodium hydroxide solution, filter, mother liquor concentrations, on residuum, silicagel column is separated to obtain 6.5g (1-(5-bromobenzene is [d] oxazole-2-base also) piperidin-4-yl) methylamine.

Claims

1. prepare the method for (1-(5-bromobenzene is [d] oxazole-2-base also) piperidin-4-yl) methylamine for one kind, with 2-amino-4-bromophenol for starting raw material, obtain target product 6 through the ring that reaches a standard, chloro, nucleophilic substitution, ammonia solution, reduction, synthetic route is as follows.

2. method according to claim 1, it is characterized by 5 described step reactions is,

(2) carry out chlorination 2, obtain 3;

(3) carry out nucleophilic substitution reaction 3 and obtain 4;

(4) carry out ammonolysis reaction 4 and obtain target product 5,

(5) carry out reduction reaction 5 and obtain target product 6,

3. according to the method for claim 1-2, it is characterized in that, the reagent that described ring closure reaction prepares compound 2 used is selected from potassium ethyl xanthonate; Described chlorination is prepared compound 3 reagent used and is selected from the mixture of one or more in sulfur oxychloride, chlorine, hydrogenchloride, phosphorus oxychloride, phosphorus pentachloride; Described nucleophilic substitution reaction is prepared compound 4 alkali used and is selected from the mixture of one or more in sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium carbonate, salt of wormwood, triethylamine, sodium bicarbonate, pyridine, triisopropylamine, saleratus; Described ammonolysis reaction is prepared compound 5 reagent used and is selected from one or both mixture in ammonia, ammoniacal liquor; Described reduction reaction is prepared compound 6 reductive agent used and is selected from the mixture of one or more in sodium borohydride, POTASSIUM BOROHYDRIDE, lithium borohydride, sodium cyanoborohydride, lithium aluminium hydride, borine, palladium carbon-hydrogen.

4. according to the method for claim 1-2, it is characterized in that, described ring closure reaction prepares compound 2 solvent selected from methanol used, ethanol, n-propyl alcohol, Virahol, tetrahydrofuran (THF), methylene dichloride, toluene, o-Xylol, p-Xylol, m-xylene, N, the mixture of one or more in dinethylformamide, N,N-dimethylacetamide, pyridine; Described chlorination is prepared compound 3 solvent used and is selected from methylene dichloride, trichloromethane, ethyl acetate, tetrahydrofuran (THF), toluene, tetrahydrofuran (THF), toluene, o-Xylol, p-Xylol, m-xylene, N, the mixture of one or more in dinethylformamide, N,N-dimethylacetamide, water; Described nucleophilic substitution reaction prepares compound 4 solvent selected from methanol used, ethanol, n-propyl alcohol, Virahol, tetrahydrofuran (THF), methylene dichloride, toluene, o-Xylol, p-Xylol, m-xylene, N, the mixture of one or more in dinethylformamide, N,N-dimethylacetamide, water; Described ammonolysis reaction prepares compound 5 solvent selected from methanol used, ethanol, n-propyl alcohol, Virahol, tetrahydrofuran (THF), methylene dichloride, trichloromethane, ethyl acetate, toluene, o-Xylol, p-Xylol, m-xylene, N, the mixture of one or more in dinethylformamide, N,N-dimethylacetamide, water; Described reduction reaction prepares compound 6 solvent selected from methanol used, ethanol, n-propyl alcohol, Virahol, tetrahydrofuran (THF), methylene dichloride, trichloromethane, ethyl acetate, toluene, o-Xylol, p-Xylol, m-xylene, N, the mixture of one or more in dinethylformamide, N,N-dimethylacetamide.

5. according to the method for claim 1-2, it is characterized in that, described ring closure reaction prepares the reflux temperature that compound 2 temperature of reaction used is 0 DEG C ~ solvent; It is 0 DEG C ~ room temperature that described chlorination prepares compound 3 temperature used; Described nucleophilic substitution reaction prepares the reflux temperature that compound 4 temperature used is 0 DEG C ~ solvent; Described ammonolysis reaction prepare compound 5 used be 0 DEG C ~ room temperature; It is 0 DEG C ~ room temperature that described reduction reaction prepares compound 6 temperature used.

6. according to the method for claim 1-2, it is characterized in that, described ring closure reaction prepares the reflux temperature that compound 2 temperature of reaction used is solvent; It is 0 DEG C ~ room temperature that described chlorination prepares compound 3 temperature used; Described nucleophilic substitution reaction prepares the reflux temperature that compound 4 temperature used is solvent; Described ammonolysis reaction prepare compound 5 used be room temperature; It is 0 DEG C ~ room temperature that described reduction reaction prepares compound 6 temperature used.