CN101704765B - Method for synthesizing freshener n-ethyl-p-menthane-3-carboxamide - Google Patents
Method for synthesizing freshener n-ethyl-p-menthane-3-carboxamide Download PDFInfo
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- MNVSUVYRIVXDBK-KXUCPTDWSA-N CC(C)[C@H](CC[C@@H](C)C1)[C@@H]1C(O)=O Chemical compound CC(C)[C@H](CC[C@@H](C)C1)[C@@H]1C(O)=O MNVSUVYRIVXDBK-KXUCPTDWSA-N 0.000 description 1
- OMLOJNNKKPNVKN-KXUCPTDWSA-N CC(C)[C@H](CC[C@@H](C)C1)[C@@H]1Cl Chemical compound CC(C)[C@H](CC[C@@H](C)C1)[C@@H]1Cl OMLOJNNKKPNVKN-KXUCPTDWSA-N 0.000 description 1
- NOOLISFMXDJSKH-KXUCPTDWSA-N CC(C)[C@H](CC[C@@H](C)C1)[C@@H]1O Chemical compound CC(C)[C@H](CC[C@@H](C)C1)[C@@H]1O NOOLISFMXDJSKH-KXUCPTDWSA-N 0.000 description 1
- 0 CC(C)[C@]1[C@@](*)C[C@](C)CC1 Chemical compound CC(C)[C@]1[C@@](*)C[C@](C)CC1 0.000 description 1
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Abstract
The invention provides a method for synthesizing a freshener n-ethyl-p-menthane-3-carboxamide. Menthol is taken as a raw material, and the method comprises the following steps: firstly, reacting the menthol with thionyl chloride in an ether compound solvent at the temperature lower than or equal to 5DEG C for 1 to 3 hours to obtain chloro menthane; secondly, performing Grignard reaction on the chloro menthane in a mixed solvent of aromatic alkanes and aliphatic ether to obtain menthyl formic acid; and finally, adding ethylamine dropwise into the menthyl formic acid at a micro-boiling temperature in the presence of an amide catalyst in a benzene, methyl benzene or dimethylbenzene solvent, continuously performing reflux reaction for 2 to 4 hours, and crystallizing to separate out the n-ethyl-p-menthane-3-carboxamide from the solvent after neutralizing, separating, and concentrating. The n-ethyl-p-menthane-3-carboxamide is yellow crystal with left-handed specific rotation [a]20D of -46.00, and the total yield is about 50 percent.
Description
One, technical field
The present invention relates to a kind of preparation method of fine chemicals, exactly is a kind of synthetic method of freshener n-ethyl-p-menthane-3-carboxamide.
Two, background information
Menthol is the most frequently used traditional freshener, because it can give product refrigerant, fresh sensation.Therefore be widely used in the industries such as food, medicine, daily use chemicals, tobacco.But the fragrance of menthol has that obvious bitter taste, cool flavor effect are weak and the time is short, high volatility, non-refractory, be slightly soluble in the shortcoming such as water.In view of the shortcomings of menthol, the application of menthol is greatly limited.In order to overcome these shortcomings of traditional coolant agent menthol, arise at the historic moment by the molecular structure of menthol being modified the various novel coolant agent that obtains.Such as: menthyl acetate, p-Menthyl lactate, menthone glycerol ketals, TK-10, n-Ethyl-2-isopropyl-5-methylcyclohexane carboxamide etc.
N-Ethyl-2-isopropyl-5-methylcyclohexane carboxamide (being called for short afterwards amide of mint) is the peppermint derivative freshener that 20 century 70 U.S. Wikirlson Sword companies at first develop, and its commodity are called WS-3, FEMA numbering 3455.Amide of mint is a kind of novel, efficient freshener with the nice and cool effect of physiological.Amide of mint is as pure freshener, and it is not with astringent taste without the fragrance breath, and cooling effect is lasting and skinfeel is gentle, and nice and cool degree is five times of mentha camphor, can cooperate well with other coolant agents, has simultaneously the flavouring effect.Can be used in chewing gum, beverage, toothpaste, candy, medicine and the tobacco articles for use such as cigarette, filter tip.Amide of mint also gets the nod in the European Community, can be used in the food, and CE number is 2298.China Ministry of Health included it in " foodstuff additive use hygienic standard " in as the spices amendments in 2002, was allowed in food, medicine and the makeup, and its China is encoded to A3149.
The amide of mint structural formula is as follows:
Amide of mint (N-ethyl-L-menthyl methane amide)
Chemical name: n-Ethyl-2-isopropyl-5-methylcyclohexane carboxamide;
English name: n-Ethyl-2-isopropyl-5-methylcyclohexane carboxamide;
CAS number: 39711-79-0;
Molecular formula: C
13H
25NO;
Specific rotation [α]
D 20-46.0 °
Although amide of mint invention history of existing three more than ten years, manufacturer is still less.One of its reason is outside the Pass the product quality of amide of mint and content have, with its 1-position chiral carbon optical purity substantial connection to be arranged.Studies show that amide of mint only has the cool flavor of levo form just pure, dextrorotation impurity mouthfeel is with strong pungent simple-minded cool feeling.Left-handed specific rotation is lower, and assorted flavor is also heavier, and assorted flavor also is difficult to cover in blending.And the left-handed and dextrorotatory isomer of amide of mint is low by method separation efficiencies such as recrystallizations.Therefore guaranteeing the R configuration of C-1 in the amide of mint commercial process, is the production technology key factor.Comprehensive domestic and foreign literature and the industrialized preparing process that has been reported, amide of mint may have following two kinds by the industrial synthesis technique route.
Article one, synthetic route is as follows:
Menthol is raw material, obtains menthyl chlorine take Lucas reagent or thionyl chloride as chlorizating agent, and menthyl chlorine and sodium cyanide reaction obtain the cyano group peppermint, with the ethyl sulfate reaction, directly prepares amide of mint again.Present method synthesis route is simple, needing to avoid the grignard reaction of anhydrous and oxygen-free operation, avoids the reaction under high pressure of grignard reagent and carbonic acid gas, and operational condition is gentle.But the fatal shortcoming of present method is to use hypertoxic sodium cyanide raw material in producing, and safety and environment protection requires high, and production management is complicated, has a big risk.
The second production method reaction scheme is as follows:
Menthol is raw material, take Lucas reagent or thionyl chloride as chlorizating agent obtains menthyl chlorine, through grignard reaction, obtains menthyl formic acid, menthyl formic acid through again through thionyl chloride acyl chloride reaction and amidate action, the preparation amide of mint.From the reaction scheme analysis, the designed reaction of the method is the conventional ripening reaction, and reaction mechanism is clear and definite, and synthetic technological condition is ripe.How ensureing that maintenance C-1 chirality is constant in the first step chlorination reaction, is committed step in present method.In addition.In existing bibliographical information, utilize ether as the industrialization solvent, processing condition require relatively harsher, complex operation, safe pressure is large in the production.For high yield carries out amidate action, with the thionyl chloride chloride of menthyl formic acid, and large usage quantity.This this method not only increases reactions steps, and the raw materials cost increase, and three-waste pollution increases.Namely be this production method in the Givaudan house journal report of Switzerland and the industrial production.
Three, summary of the invention
The present invention aims to provide a kind of commercial freshener-amide of mint, and technical problem to be solved is to meet the commercial product that requires by the left-handed specific rotation of synthetic directly preparation.
The commercial amide of mint that requires that meets that the present invention is alleged refers to left-handed specific rotation [α]
D 20-46.0 ° amide of mint.
The operational path of this synthetic method is shown in the following formula:
As seen this synthetic method is also to be as starting raw material take menthol, comprise each unit process of chlorination, carboxylation reaction and amidate action and aftertreatment, difference with the prior art is that described chlorination is that the chlorination reagent thionyl chloride of raw material menthol reacted 1～3 hour under ℃ condition of temperature≤5 in the solvent of ether compound, separates obtaining chlorination menthane (menthyl chlorine); The chloro menthane is carboxylated through grignard reaction in the mixed solvent of aromatic series alkane and fatty ether, obtains menthyl formic acid; Described amidate action is that menthyl formic acid drips ethamine under little temperature of boiling when having amide catalysts to exist in benzene, toluene or xylene solvent, drip off rear continuation back flow reaction 2～4 hours, amide of mint crystallization in solvent after neutralizing, separate, concentrating is the yellow crystal shape.The add-on of amide catalysts is 5～15% of menthyl formic acid mole number.
The ether compound solvent is selected from one or more miscible agents of dioxy six alkane or fatty ether such as methyl tertiary butyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, propylene glycol monobutyl ether or ethylene glycol diethyl ether etc. in the described chlorination.During the application mix solvent, ratio is any mutually.Theoretical and experimental study shows that dioxy six alkane are best reaction solvents; But dioxy six alkane costs are high, and toxicity is relatively large, reclaim relative complex.The preferred aliphat ethers is as reaction solvent.
Mixed solvent in grignard reaction, described aromatic series alkane is selected from benzene, toluene or dimethylbenzene etc., and it is 1: 10～10: 1 that described fatty ether is selected from both volume mixture ratios such as methyl tertiary butyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, propylene glycol monobutyl ether or ethylene glycol diethyl ether.
Amide catalysts is selected from dicyclohexyl carbimide (DCC), 1-ethyl-(3-dimethylaminopropyl) phosphinylidyne diimine (EDAC) or azide diphenyl phosphate (DPPA) etc. in the described amidate action.
Present method used cyclic ethers or aliphatic ether is made solvent, thionyl chloride is chlorination reagent in chlorination, not only side reaction is few, chloro-product yield high (〉=85%), particularly the C-1 chiral configuration is stablized constant in the chloro-product, guarantee that the finished product have high left-handed rotation activity, quality product is high.Compare with traditional method, although the Lucas reagent relative low price, consumption is large, and three-waste pollution is high; More important is that side reaction is many in the chlorination process, and the chloro-product yield is on the low side, and C-1 chiral configuration racemize ratio is high, and the finished product specific rotation can not guarantee.Ether solvent is with respect to DMF solvent low price, and dewatering process is simple and convenient in the recycling process, and cost recovery is low, and the rate of recovery is high.
Present method is used fragrant alkane and aliphatic ether mixed solvent in carboxylation reaction, compare with traditional ether or tetrahydrofuran solvent that volatility is less, boiling point is higher, can prevent the solvent bumping that the grignard reaction very exothermic causes, grignard reaction is carried out reposefully, processing safety improves greatly, reduce simultaneously the side reactions such as coupling, improve carboxylated transformation efficiency.
Present method is used the reactive behavior of catalyst activation carboxyl in amidate action, with ethamine with the direct amidation of carboxyl, than traditional first chloride, again amidation technique, reactions steps is few, work simplification, and in reaction process, utilize benzene, toluene, the characteristics of dimethylbenzene and water azeotropic adopt the reaction fractionating technology, the water that reaction generates is removed, reversible reaction is moved to the resultant direction, greatly improve the transformation efficiency of menthyl formic acid, improve product yield.
Four, embodiment
Non-limiting examples of the present invention is described below:
Synthesizing of 1 menthyl chlorine
Thermometer 500ml there-necked flask is being housed, add 78g menthol (0.5mol) and 150ml methyl tertiary butyl ether, temperature of reaction is controlled at 0 ℃, slowly drips 71.4g thionyl chloride (0.6mol) in reaction solution, dropwise rear vigorous stirring 2h, stopped reaction.In reaction solution, add the 100ml frozen water, stirring at room 0.5h, tail gas can be processed with alkali liquor absorption.With saturated sodium bicarbonate solution regulator solution pH7.0～7.5, then reaction solution is extracted with methyl tertiary butyl ether, extraction phase repeatedly washs with saturated aqueous common salt, drying, suction filtration removes solvent under reduced pressure, then underpressure distillation, collect 47-51 ℃/199Pa cut, obtain menthyl chlorine 74.2g, productive rate 86%.
The specific rotation [a] that menthyl chloride is measured
20 DBe-52.1 °, diopter is n
20 D=1.4633.Take gas chromatographic analysis (condition is as column temperature: 180 ℃, detected temperatures: 250 ℃, vaporization temperature: 250 ℃), purity is 97%.MS(EI)，m/Z：174(M
+)。
1HNMR(CDCl
3)，δ：0.81(3H，d)，0.95(6H，d)，1.04(2H，m)，1.60(2H，m)，1.75(1H，m)，2.01(1H，m)，2.24(1H，m)，3.81(1H，m)。
Synthesizing of 2 menthyl formic acid
The left-handed chloro menthane 87.3g (0.5mol) of drying is dissolved in 150ml toluene and methyl tertiary butyl ether (toluene: methyl tertiary butyl ether=1: 3V/V) add and be equipped with in the 500ml there-necked flask of reflux condensing tube, add 14.4g (0.6mol) magnesium chips and several iodine, stirring heating backflow 1～3h.Then reaction solution is cooled to room temperature, and ice bath slowly passes into CO in reaction solution under ice bath
2Gas keeps temperature of reaction below 10 ℃; Ventilate after two hours, the beginning sampling analysis, after this every sampling half an hour once, until menthyl chlorine complete reaction.Detection method be negate answer solution a little, with saturated aqueous ammonium chloride cancellation reaction soln, gas chromatographic analysis menthane content.Ventilate approximately after 2-3 hour, Ge Shi intermediate primitive reaction is complete, with a small amount of unreacted form intermediate of saturated aqueous ammonium chloride cancellation, stirs half an hour, separatory.Water extracts with methyl tertiary butyl ether.Extraction liquid mixes with organic phase, and drying removes solvent under reduced pressure, gets menthyl formic acid 66.2g, productive rate 72%.Take gas chromatographic analysis (condition is as column temperature: 180 ℃, detected temperatures: 250 ℃, vaporization temperature: 250 ℃), purity 96%.Again obtain menthyl-3-carboxylic acid after the distillation and carry out nmr analysis,
1HNMR (CDCl
3), δ: 0.81 (3H, d), 0.95 (6H, d), 1.04 (2H, m), 1.60 (2H, m), 1.75 (1H, m), 2.01 (1H, m), 2.24 (1H, m), 2.30 (1H, m), 11.0 (1H, s).
Synthesizing of 3 amide of mint
After in the 250ml reaction flask that stirring, thermometer and reflux water-dividing device are housed, adding the 100ml toluene solvant, add again menthyl formic acid 46g (0.25mol) and DCC 0.025mol, stirring heating; When reaction mass is in little reflux state, slowly in reaction mixture, drip 20g 70% ethamine (0.31mol), reflux simultaneously in the reaction process and separate water outlet, after dripping, refluxed again 3h hour.Extremely neutral with rare HC1 solution neutralization reaction mixture, separatory.Water extracts with toluene, merges with organic phase.Then drying revolves the steaming toluene solvant, obtains light yellow crystal after the placement, uses acetone: water ((C
2H
6O): (H
2O)=1: 1V/V) the solution weight crystallization repeatedly gets amide of mint 41.7g, productive rate 79.2%.
Product is take gas chromatographic analysis (condition is as column temperature: 200 ℃, detected temperatures: 250 ℃, vaporization temperature: 250 ℃), and purity is 99%.Fusing point: 84-86 ℃.MS(EI)，m/Z：211(M
+)。
1HNMR(CDCl
3)，δ：0.81(3H，d)，0.95(6H，d)，1.04(5H，m)，1.60(2H，m)，1.75(1H，m)，2.01(1H，m)，2.24(1H，m)，3.24(2H，m)，3.81(1H，m)，8.03(1H，s)。[a]
D 20＝-46°。
Claims (2)
1. the synthetic method of a freshener n-ethyl-p-menthane-3-carboxamide take menthol as raw material, comprises each unit process of chlorination, carboxylation reaction and amidate action and aftertreatment, it is characterized in that:
(1) described chlorination is that menthol and thionyl chloride react under ℃ condition of temperature≤5 in the ether compound solvent and obtained the chloro menthane in 1～3 hour;
(2) described amidate action is that menthyl formic acid drips ethamine under little temperature of boiling when having amide catalysts to exist in benzene, toluene or xylene solvent, drip off rear continuation back flow reaction 2～4 hours, the amide catalysts add-on is 5～15% of menthyl formic acid mole number;
The ether compound solvent is selected from one or more mixed ethers in dioxane, methyl tertiary butyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, propylene glycol monobutyl ether or the ethylene glycol diethyl ether in the described chlorination; Amide catalysts is selected from dicyclohexyl carbimide, 1-ethyl-(3-dimethylaminopropyl) phosphinylidyne diimine or azide diphenyl phosphate in the described amidate action.
2. synthetic method according to claim 1, it is characterized in that: described ether compound solvent is selected from one or more mixed ethers in methyl tertiary butyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, propylene glycol monobutyl ether or the ethylene glycol diethyl ether.
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| CN103796535B (en) * | 2011-09-01 | 2016-09-28 | 高砂国际有限公司（美国） | New substituted compounds |
| CN102531885B (en) * | 2011-12-20 | 2013-10-30 | 上海灏翔生物科技有限公司 | Method for synthesizing L-peppermint carboxylic acid |
| CN103030553A (en) * | 2012-11-26 | 2013-04-10 | 安徽一帆香料有限公司 | Synthesis method of menthylformic acid |
| CN103304370B (en) * | 2013-06-03 | 2015-02-04 | 安徽中草香料有限公司 | Synthesis method of 5-methyl-2-isopropyl chlorocyclohexane |
| CN104649896A (en) * | 2015-01-15 | 2015-05-27 | 泛亚欧劳福林（武汉）生物科技有限公司 | Preparation method of menthyl formate |
| CN106946729B (en) * | 2017-03-27 | 2018-10-16 | 万华化学集团股份有限公司 | A kind of preparation method of L- N-Ethyl-p-menthane-3-carboxamide class compound |
| CN109851522B (en) * | 2018-12-10 | 2022-03-11 | 万华化学集团股份有限公司 | Method for preparing N-ethyl-L-menthyl formamide by inversion of N-ethyl-neo-menthyl formamide configuration |
| CN111393293B (en) * | 2020-05-07 | 2022-09-20 | 万华化学集团股份有限公司 | Ester ammonolysis reaction catalyst composition and preparation method of L-menthane carboxamide |
| CN114917190A (en) * | 2022-06-13 | 2022-08-19 | 郑州味千生物技术有限公司 | Product for masking bitter taste |
| CN115806481A (en) * | 2022-12-05 | 2023-03-17 | 安徽丰乐香料有限责任公司 | Separation and purification method of L-menthyl formic acid |
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| CN1613845A (en) * | 2003-11-05 | 2005-05-11 | 哈尔滨天发日化有限责任公司 | Preparation of amidated natural metha camphor as effective algefacient |
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