Method for synthesizing cis-and trans-menthone-8-thioacetate

A synthesis method and technology of menthone are applied in the synthesis field of cis and trans-menthone-8-thiol acetate, can solve problems such as low conversion rate and high price, and achieve mild reaction, simple operation and high yield. Effect

CN102816094AInactive Publication Date: 2012-12-12TIANNING FLAVOR JIANGSU
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Patent Information

Authority / Receiving Office
CN · China
Current Assignee / Owner
Publication Date
2012-12-12
Estimated Expiration
Not applicable · inactive patent

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Abstract

The invention discloses a method for synthesizing cis-and trans-menthone-8-thioacetate. Para-mentha-8-thiolone is used as a starting material. The method includes the following steps of acetylation, neutralization by washing materials and fractionation, wherein the acetylation includes that the para-mentha-8-thiolone is added into acetic anhydride, sodium acetate anhydrous is selected as a catalyst, the amount of the sodium acetate anhydrous is 0.1% to 1%, an acetic acid generated during the reaction process is distilled, and the reaction time is 20 hours to 40 hours; the neutralization by washing materials includes washing a material liquid by a sodium carbonate aqueous solution; and the fractionation includes removing former fraction to distill out a finished product. The method for synthesizing the cis-and trans-menthone-8-thioacetate has the advantages that the isomer is few, the reaction is mild, the process is simple, and the yield is high.
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Description

technical field

[0001] The invention relates to a method for synthesizing cis and trans-menthone-8-thiol acetates. Background technique

[0002] Cis-and trans-menthone-8-thioacetate (Cis-and trans-menthone-8-thioacetate) has a mint-like aroma, which is similar to 8-thiomenthone, but the aroma is softer and less sulfurous. Exist in buku leaf oil, which is a natural equivalent spice. Acetate cis and trans-menthone-8-thiol esters are expensive, but few related preparation methods have been published. The general reaction is easy to generate pulegone, and the conversion rate is quite low. Contents of the invention

[0003] The purpose of the present invention is to provide a kind of synthetic method of acetate cis and trans-menthone-8-thiol ester, and this synthetic method process is simple, and yield is high.

[0004] A kind of synthetic method of cis and trans-menthone-8-thiol acetate, comprises the following steps:

[0005] 1. Acetylation:

[0006] Add 1 part of 8-thio...

Examples

Embodiment 1

[0013] A kind of synthetic method of cis and trans-menthone-8-thiol acetate, carries out following steps successively:

[0014] 1), Acetylation: Add 120-240g acetic anhydride, 0.04-0.4g anhydrous sodium acetate, 40g thiomenthone into a 250ml three-necked flask, heat up to 100-120°C, and distill out the generated Acetic acid until the 8-thiomenthone content in the reaction system is less than 1% according to GC analysis, under vacuum conditions, the excess acetic anhydride after the reaction is distilled out, and the reaction time is 30 hours.

[0015] 2) Neutralization and washing: add the remaining liquid in the reaction bottle to a 500ml separating funnel, then add 300ml of 10% sodium carbonate aqueous solution to shake fully, let it stand, separate the alkaline water, and wash it once with clean water to obtain 49.6g of crude material.

[0016] 3) Distillation: Add 0.25g of sodium chloride to the crude material during distillation, and gradually increase the internal temper...

Embodiment 2

[0018] A kind of synthetic method of cis and trans-menthone-8-thiol acetate, carries out following steps successively:

[0019] 1) Acetylation: Add 300-600g of acetic anhydride, 0.1-1.0g of anhydrous sodium acetate, and 100g of thiomenthone into a 1000ml three-necked flask, heat up to 100-120°C, and distill out the generated during the reaction under vacuum conditions Acetic acid, until the 8-thiomenthone content in the reaction system is less than 1% according to GC analysis, under vacuum conditions, the excess acetic anhydride after the reaction is distilled out, and the reaction time is 35 hours.

[0020] 2) Neutralization and washing: Add the remaining liquid in the reaction bottle to a 1000ml separating funnel, then add 750ml of 10% sodium carbonate aqueous solution to shake fully, let it stand, separate the alkaline water, and wash it once with clean water to obtain 125.3g of crude material.

[0021] 3) Distillation: Add 0.625g of sodium chloride to the crude material du...