The preparation method of isopropyl-β-D-thiogalactoside(IPTG)
technical field
The present invention relates to sugar compounds field, be specifically related to a kind of preparation method of isopropyl-β-D-thiogalactoside(IPTG).
background technology
Isopropyl-β-D-thiogalactoside(IPTG), claims again IPTG, English name: Isopropyl β-D-1-Thiogalactopyranoside, No. CAS: 367-93-1, molecular formula C
9h
18o
5s, structural formula is as follows:
In the prior art, general semi-lactosi and the aceticanhydride of adopting reacts preparation five acetyl semi-lactosis under the effect of sodium-acetate, five acetyl semi-lactosis are dissolved under catalyst and tetrem acyl isopropylthio semi-lactosi is prepared in isopropyl mercaptan reaction, tetrem acyl isopropylthio semi-lactosi is prepared isopropyl-β-D-thiogalactoside(IPTG) through the de-acetyl of sodium methylate, this method is first prepared five acetyl semi-lactosis, purify and caused certain raw materials consumption, operate more loaded down with trivial detailsly, cost is higher.Patent for example: 201210553464; another kind method is to take penta-acetyl semi-lactosi to generate semi-lactosi isothiourea fluoro salt as raw material reacts with thiocarbamide; semi-lactosi isothiourea fluoro salt and different bromopropane reaction generate sec.-propyl-β-D-sulfo-four acetylglactosides; then de-acetyl obtains isopropyl-β-D-thiogalactoside(IPTG); this route steps is many; complicated operation, cost is higher, for example patent: 201310010582.7.
summary of the invention
High in order to solve the cost compare existing in the preparation of isopropyl-β-D-thiogalactoside(IPTG) in above prior art, operate more numerous and diverse, the present situation that yield is lower, the invention provides a kind of two-step approach, the method for preparing isopropyl-β-D-thiogalactoside(IPTG) that simple to operate, raw material is easy to get of adopting.
The present invention is achieved by the following measures:
A preparation method for isopropyl-β-D-thiogalactoside(IPTG), comprises the following steps:
A) room temperature adds aceticanhydride and catalyzer, divides 9 batches and adds semi-lactosi, after having reacted, adds isopropyl mercaptan, has reacted by processing and obtain isopropylthio acetyl semi-lactosi later;
B) isopropylthio acetyl semi-lactosi is added in methyl alcohol and is dissolved, add sodium methylate, after having reacted, add acetic acid neutralization, through aftertreatment, obtain isopropyl-β-D-thiogalactoside(IPTG);
Aceticanhydride in step a: catalyzer: semi-lactosi: the mol ratio of isopropyl mercaptan is 5.5: 1: 1:1.1.
Described method, isopropylthio acetyl semi-lactosi: the mol ratio of sodium methylate is 1:0.01-0.06.
Described method, in step a, temperature of reaction is 5-10 ℃.
Described method, in step a, catalyzer is aluminum chloride, iron trichloride, zinc chloride.
Described method, in step a, the reaction times is 16-24 hour, in step b, the reaction times is 2-4 hour.
Described method, in step a, aftertreatment is cancellation, extraction, washing, concentrated, add mixed solvent crystallization.
Described method, in step b aftertreatment dry for being concentrated into, add mixed solvent crystallization.
In described method steps a, mixed solvent is that mol ratio is the t-butyl methyl ether of 1:2-3 and the solvent mixture of isohexane.
Described method, in step b, mixed solvent is that mol ratio is the ethanol of 1:5-10 and the solvent mixture of t-butyl methyl ether.
Beneficial effect: the inventive method adopts different reaction systems, comprises catalyzer, treatment processs etc. only obtain product by two-step reaction, have effectively improved safety coefficient and product; Simple to operate, raw material is easy to get, and has saved running cost and material.
Embodiment
In order further to understand the present invention, below in conjunction with specific embodiment, the process of this programme is described, but should be appreciated that these are described is for further instruction the features and advantages of the present invention, rather than limiting to the claimed invention.
embodiment 1
A) room temperature adds 5.5mol aceticanhydride and 1mol aluminum chloride, 5-10 ℃ minute 9 batches add 1mol semi-lactosi, after having reacted, add 1.1mol isopropyl mercaptan, reacted by later processing and obtain 0.765mol isopropylthio acetyl semi-lactosi;
B) 0.765mol isopropylthio acetyl semi-lactosi is added in 10mol methyl alcohol and is dissolved, add 0.01mol sodium methylate, after having reacted, add the neutralization of 0.01mol acetic acid, through aftertreatment, obtain 0.743mol isopropyl-β-D-thiogalactoside(IPTG).Yield is 74.3%.
In step a, aftertreatment is stirred 2 hours for dripping the water of 0-5 ℃ of 10mol, by the dichloromethane extraction aqueous layer extracted of 5mol, separates organic phase 10mol water washing organic phase three times, separate organic phase concentrated, the isohexane mixed solution crystallization that adds 1mol t-butyl methyl ether and 2mol, filters, dry.
In step b, aftertreatment is dry for being concentrated into, and adds the crystallization of 0.2mol ethanol and 1.8mol t-butyl methyl ether, filters, dry.
control Example
A) room temperature adds 15mol aceticanhydride and 0.15mol sodium-acetate, divides 12 batches and add 1mol semi-lactosi under condensing reflux, after having reacted, adds the water of 100mol, separates out yellow scape solid, and the recrystallization of the ethanol of process 5mol obtains the five acetyl semi-lactosis of 0.51mol;
B) the five acetyl semi-lactosis of 0.51moll are added in the methylene dichloride of 10mol, the boron trifluoride diethyl etherate that adds 0.75mol, at 0-5 ℃ of isopropyl mercaptan that adds 1.25mol, stir 2 hours, reacted the isopropylthio acetyl semi-lactosi that rear aftertreatment obtains 0.453mol;
C) 0.453mol isopropylthio acetyl semi-lactosi is added in 10mol methyl alcohol and is dissolved, add 0.01mol sodium methylate, after having reacted, add the neutralization of 0.01mol acetic acid, through aftertreatment, obtain 0.452mol isopropyl-β-D-thiogalactoside(IPTG).Yield is 45.2%.
In step b, aftertreatment is stirred 2 hours for dripping the water of 0-5 ℃ of 10mol, dichloromethane extraction aqueous layer extracted with 5mol, separate organic phase 10mol water washing organic phase three times, separate organic phase concentrated, the isohexane mixed solution crystallization that adds 0.5mol t-butyl methyl ether and 1mol, filter, dry.