Method for preparing 3,4-dihydrobenzo[b][1,4]oxazine derivatives

A technology of dihydrobenzene and oxazine, which is applied in the field of preparing 3,4-dihydrobenzo[b][1,4]oxazine derivatives, can solve the problems of high metal catalyst price and difficult removal of metal residues, etc. Achieve the effect of large industrialization potential, high reactivity, and wide range of substrates

Active Publication Date: 2016-06-15
INST OF CHEM CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The reported synthetic methods have certain defects, the metal catalysts used are expensive and the metal residues are difficult to remove

Method used

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  • Method for preparing 3,4-dihydrobenzo[b][1,4]oxazine derivatives
  • Method for preparing 3,4-dihydrobenzo[b][1,4]oxazine derivatives
  • Method for preparing 3,4-dihydrobenzo[b][1,4]oxazine derivatives

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0081] Example 1. Synthesis of 3-(2-thiophene)-3,4-dihydrobenzo[b][1,4]oxazine (see structural formula I-a)

[0082] according to figure 1 The synthetic route shown to prepare the compound represented by formula I-a, the specific operation is as follows:

[0083] In the glove box, add 3-(2-thiophene)benzo[b][1,4]oxazine (shown in formula II-a) (0.086g, 0.4mmol), tris(pentafluoro Phenyl)borane (0.0051 g, 0.01 mmol), and 0.2 mL of toluene. Put the reaction sleeve into the autoclave and tighten the kettle, fill it with hydrogen 20bar, and react at 50°C for 6h; after the reaction is completed, remove the solvent, and the conversion rate measured by NMR is> 99%, column chromatography, the specific conditions are: the specification of the chromatography column is 20cm in diameter×200cm in height, the filler is 200-300 mesh silica gel, the column is packed with petroleum ether, and the eluent is ethyl acetate with a volume ratio of 1:10 The mixture of ester and petroleum ether, the flow ...

Embodiment 2

[0086] Example 2. Synthesis of 3-(1-naphthyl)-3,4-dihydrobenzo[b][1,4]oxazine (see structural formula I-b)

[0087] according to figure 2 The synthetic route shown to prepare the compound represented by formula I-b, the specific operation is as follows:

[0088] In the glove box, add 3-(1-naphthyl)benzo[b][1,4]oxazine (shown in formula II-b) (0.104g, 0.4mmol), three (5 Fluorophenyl)borane (0.0051 g, 0.01 mmol), and 0.2 mL of toluene. Put the reaction sleeve into the autoclave and tighten the kettle, fill it with hydrogen 20bar, and react at 50°C for 6h; after the reaction is completed, remove the solvent, and the conversion rate measured by NMR is> 99%, chromatography column, the specific conditions are: the specification of the chromatography column is 20cm in diameter×200cm in height, the filler is 200-300 mesh silica gel, the column is packed with petroleum ether, and the eluent is ethyl acetate with a volume ratio of 1:10 The mixture of ester and petroleum ether, the flow rat...

Embodiment 3

[0091] Example 3. Synthesis of 3-(3,4-dichlorophenyl)-3,4-dihydrobenzo[b][1,4]oxazine (see structural formula I-c)

[0092] according to image 3 The shown synthetic route prepares the compound represented by formula I-c, the specific operation is as follows:

[0093] In the glove box, sequentially add 3-(3,4-dichlorophenyl)benzo[b][1,4]oxazine (shown in formula II-c) (0.111g, 0.4mmol) into the sleeve , Tris(pentafluorophenyl)borane (0.0051 g, 0.01 mmol), and 0.2 mL of toluene. Put the reaction sleeve into the autoclave and tighten the kettle, fill it with hydrogen 20bar, and react at 50°C for 6h; after the reaction is completed, remove the solvent, and the conversion rate measured by NMR is> 99%, column chromatography, the specific conditions are: the specification of the chromatography column is 20cm in diameter×200cm in height, the filler is 200-300 mesh silica gel, the column is packed with petroleum ether, and the eluent is ethyl acetate with a volume ratio of 1:10 The mixtur...

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Abstract

The invention provides a method for preparing 3,4-dihydrobenzo[b][1,4]oxazine derivatives. The method comprises the following step: carrying out reduction reaction on [b][1,4]oxazines in the presence of hydrogen gas by using B(C6F5)3 as a catalyst to obtain the mixture containing the 3,4-dihydrobenzo[b][1,4]oxazines disclosed as Formula I. Benzo[b][1,4]oxazines in different structures are used as a substrate to synthesize the benzo[b][1,4]oxazines at high yield by using the B(C6F5)3 as the catalyst. The method has the advantages of cheap and accessible raw materials, high reaction activity, no participation of transition metals and wide substrate application range, and has huge industrialization potential.

Description

Technical field [0001] The invention belongs to the field of organic synthesis, and specifically relates to a method for preparing 3,4-dihydrobenzo[b][1,4]oxazine derivatives. Background technique [0002] The 3,4-dihydrobenzo[b][1,4]oxazines represented by formula I play a very important role in organic synthesis and have potential biological activities. The skeletons of these compounds are widely found in a variety of biologically active natural products. Among them, levofloxacin derived from 3,4-dihydrobenzo[b][1,4]oxazine compounds is a mature commercial drug. . [0003] [0004] In the formula I, R 1 Is any one of methyl, chlorine and bromine atoms; R 2 Any one selected from naphthyl, phenyl, substituted phenyl and thienyl; [0005] At present, the method for preparing 3,4-dihydrobenzo[b][1,4]oxazine in organic synthesis mainly uses transition metal to catalyze the hydrogenation of benzo[b][1,4]oxazine derivatives with hydrogen. It is obtained by reaction, and it is obtained ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D265/36C07D413/04
CPCC07D265/36C07D413/04
Inventor 杜海峰魏思敏
Owner INST OF CHEM CHINESE ACAD OF SCI
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