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A method of preparing cyclopenten/cyclohexen-1-yl-boronic acid pinacol ester

A technology of cyclopentane, alcohol ester, applied in the field of pharmaceutical intermediate synthesis, can solve the problems of high cost, unsuitable solvent for amplification, etc., and achieves the effects of simple operation, strong continuity and few by-products

Active Publication Date: 2015-07-22
CANGZHOU PURUI DONGFANG SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] The above synthetic methods have the disadvantages of high cost, unsuitable solvents for scale-up, and the need for ultra-low temperature.

Method used

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  • A method of preparing cyclopenten/cyclohexen-1-yl-boronic acid pinacol ester

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0017] Embodiment 1: a kind of method for preparing cyclopentene-1-boronic acid pinacol ester, comprises the following steps:

[0018] Add 126g (1mol) of methyl cyclopentene-1-carboxylate and 280mL of dichloromethane into the reaction flask, slowly add 500mL (1.5mol) of 3M KOH aqueous solution at room temperature, after the addition is complete, stir and react for 1-2 hours, After TLC detects that the raw materials disappear, add 2M hydrochloric acid to adjust the pH to 4-5, separate the organic layer, add 150mL dichloromethane to the aqueous layer, separate the layers again, combine the organic layers, and wash with saturated brine to obtain cyclopentene The dichloromethane solution of -1-carboxylic acid, with a purity of more than 98% (after deducting the solvent) as detected by GC, was directly used in the next reaction.

[0019] Add the dichloromethane solution of the above-mentioned cyclopentene-1-carboxylic acid in the reaction flask equipped with a dropping funnel, a re...

Embodiment 2

[0021] Embodiment 2: a kind of method for preparing cyclohexene-1-boronic acid pinacol ester, comprises the following steps:

[0022] Add 70g (0.5mol) of methyl cyclohexene-1-carboxylate and 200mL of dichloromethane into the reaction flask, slowly add 250mL (0.75mol) of 3M KOH aqueous solution at room temperature, and stir for 1-2 hours after the addition is complete , after the disappearance of the raw materials detected by TLC, 6M hydrochloric acid was added to adjust the pH to 4-5, the organic layer was separated, and 100 mL of dichloromethane was added to the aqueous layer. The dichloromethane solution of alkene-1-carboxylic acid has a purity of more than 97% (after deducting the solvent) as detected by GC, and is directly used in the next reaction.

[0023] Add the dichloromethane solution of the above-mentioned cyclohexene-1-carboxylic acid in the reaction flask equipped with a dropping funnel, a reflux condenser and a distillation device, and add bromine 76.8g (0.48mol)...

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Abstract

The invention discloses a method of preparing cyclopenten / cyclohexen-1-yl-boronic acid pinacol ester from methyl 1-cyclopentene / cyclohexene-1-carboxylate by three-step continuous operations. The method includes subjecting the raw material to alkaline hydrolysis to form the corresponding 1-alkylene carboxylic acid; performing addition with bromine; performing elimination and decarboxylation at the same time under the existence of DBU or DMAP to produce 1-bromo cyclopentene / cyclohexene; and allowing the 1-bromo cyclopentene / cyclohexene and methoxyboronic acid pinacol ester to form an ester under the existence of magnesium metal by a one-pot process to obtain the cyclopenten / cyclohexen-1-yl-boronic acid pinacol ester. The method is high in continuity, simple and convenient in operations, free of low-temperature reactions, and capable of obtaining the 1-bromo cyclopentene / cyclohexene intermediate with high purity and meeting market demands. The method adopts one-pot-process of Grignard reaction / esterification, so that the method is more convenient in operations and has less by-products, and the product is easier in rectification purification.

Description

technical field [0001] The invention relates to a method for preparing cyclopent(hex)ene-1-boronic acid pinacol ester, which belongs to the field of synthesis of pharmaceutical intermediates. Background technique [0002] The synthesis of cyclopent(hex)enyl borate has always been a difficult point in the research of boron chemistry. The existing synthetic methods mainly include: 1) Starting from a cyclic ketone, it becomes a cycloalkene- 1-Chloro / bromine / iodine / OTf, and then in ether with metal lithium and boron reagents (reference: WO2012 / 148511A1) or metal palladium catalyzed with biboronic acid pinacol ester coupling (reference: J.Am.Chem .Soc., 2002,124,8001); 2) Starting from cyclic ketones, under copper catalysis, addition with biboronic acid pinacol ester, followed by elimination in the presence of TsOH to obtain (reference: J.Org.Chem ., 2014, 79, 7199); 3) starting from cyclic ketones, first with TsNHNH 2 Dehydration reaction occurs, followed by reaction with meta...

Claims

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Application Information

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IPC IPC(8): C07F5/02
CPCC07F5/02
Inventor 冷延国桂迁张进余锦华
Owner CANGZHOU PURUI DONGFANG SCI & TECH
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