Preparation method of 2-methylthio-5-benzothiazole

A technology of bromobenzothiazole and mercaptobenzothiazole, which is applied in the field of synthesis of organic compounds, can solve the problems of large discharge of three wastes, long synthesis route, and low reaction yield, and achieve less discharge of three wastes, reduced corrosion, and high reaction yield high effect

Inactive Publication Date: 2011-04-13
ZHEJIANG UNIV
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Problems solved by technology

[0003] The above-mentioned method has the following disadvantages: the synthetic route is long, the nitrification and diazotization all have relatively large potential safety hazards, and the reaction yield is low, the discharge of three wastes is large, and the production cost is high

Method used

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  • Preparation method of 2-methylthio-5-benzothiazole
  • Preparation method of 2-methylthio-5-benzothiazole
  • Preparation method of 2-methylthio-5-benzothiazole

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Embodiment 1

[0025] Embodiment 1, a kind of preparation method of 2-ethylthiobenzothiazole, take 2-mercaptobenzothiazole as starting material, carry out the following steps successively:

[0026] A 1000mL three-neck round bottom flask was equipped with a mechanical stirring paddle, a spherical condenser, and a constant pressure dropping funnel. Add 250mL of industrial ethanol and 160mL of 20% (mass concentration) sodium hydroxide aqueous solution, and heat to reflux. 100 g of 2-mercaptobenzothiazole was thrown into the flask at one time, and stirred to obtain a pale yellow clear reaction liquid. Measure 50 mL of ethyl bromide and add it dropwise to the flask within 1 hour. After the dropwise addition, continue to react for 2 hours. It is found that the raw materials have been consumed by TLC monitoring. After the reaction solution was cooled to room temperature, it was separated into two phases. After the lower organic phase was separated, 50 mL of dichloromethane was added, washed with wa...

Embodiment 2

[0027] Embodiment 2, a preparation method of 2-ethylthio-5-bromobenzothiazole, using 2-ethylthiobenzothiazole as a starting material, the following steps are carried out in sequence:

[0028] Dissolve 2-ethylthiobenzothiazole (9.77 g, 50.0 mmol) in 100 mL CHCl 3 , transferred to a 250mL three-necked flask equipped with a mechanical stirring paddle, a thermometer, and a spherical condenser, started stirring, and refluxed at 60°C. Commercialized NBS (13.4 g, 75.0 mmol) was added into the flask at one time, and the reaction solution gradually turned yellow, orange, orange red until dark red. GC detection, 9h to stop the reaction. After the resulting reaction solution was cooled to room temperature, filter it to remove succinimide as a by-product, and wash the obtained filtrate with saturated sodium bicarbonate solution (30mL×3) until the reddish-brown color disappeared, and the organic phase was basically pale. Until it becomes yellow (that is, remove a small amount of bromine ...

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Abstract

The invention discloses a preparation method of 2-methylthio-5-benzothiazole, successively comprising the following steps: 1) mixing ethanol, a sodium hydroxide solution, 2-mercaptobenzothiazole and bromoethane to react until the 2-mercaptobenzothiazole is completely reacted; 2) cooling the product obtained by step 1) to room temperature, splitting phases, washing, and carrying out reduced pressure distillation and the like to obtain 2-methylthio benzothiazole; 3) dissolving the 2-methylthio benzothiazole into low-grade halohydrocarbon, and adding N-bromosuccinimide to react; and 4) after the reactive fluid obtained in step 3) is cooled to room temperature, successively filtering, washing, drying and carrying out reduced pressure distillation to obtain the wax-state solid product of the salmon 2-methylthio-5-benzothiazole. The 2-methylthio-5-benzothiazole prepared according to the method disclosed in the invention has the characteristics of simple technology, high yield, low cost, small three-waste discharge and the like.

Description

technical field [0001] The invention relates to a method for synthesizing organic compounds, in particular to a method for synthesizing 2-ethylthio-5-bromobenzothiazole (5-bromo-2-(ethylthio)benzo[d]thiazole). Background technique [0002] 2-Ethylthio-5-bromobenzothiazole, which has the formula C 9 h 8 BrNS 2 , the structural formula is shown in formula 1; it is an important intermediate for the synthesis of a new type of cancer treatment drug enzyme kinase inhibitor IGF-1R, in the patent WO2007056170, the synthetic method used is based on 2-mercapto-5-bromobenzothiazole The target product is obtained by reacting the starting material with a halogenated hydrocarbon. According to the literature (W.A.Boggust and W.Cocker, Journal of the Chemical Society (Resumed) 1949, 355-362.), the method of introducing the bromine atom at the 5-position of the benzothiazole ring: through nitration and reduction to obtain 5-amino Benzothiazole, and then diazotization and Sandmeyer reacti...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D277/74
Inventor 陈新志计立钱超
Owner ZHEJIANG UNIV
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