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Spliting method for DL-pantoyl intenral ester

A technology of pantothenolactone and resolution agent, which is applied in the field of resolution of DL-pantothene lactone, can solve the problems of low resolution yield, low resolution yield and large dosage of L-calcium pantothenate, and achieve The effect of improving the total utilization rate, reducing production costs, and high split yield

Inactive Publication Date: 2005-05-04
ZHEJIANG NHU CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The shortcoming of this method is that the resolution yield of L-calcium pantothenate is low, then the effective utilization rate of L-calcium pantothenate is low, and production cost is higher
The existing improved method is to firstly split DL-pantothenolactone, the main intermediate of DL-pantothenate calcium, with a resolving agent to obtain L-pantothenolactone and D-pantothenolactone. The acylation reaction of lactone and β-alanine undergoes chiral transformation to obtain D-calcium pantothenate, and D-pantothenate is re-resolved after heating and racemization, which reduces the production cost of D-calcium pantothenate. The resolving agent is mainly organic bases such as D-chloramphenol (a synthetic by-product) and natural product quinine. Reaction, the selectivity when splitting DL-panthenolactone is low, thereby the total utilization rate of DL-panthenolactone is low, and the resolving agent used is when resolving DL-panthenolactone, resolving agent The required amount is large and the resolving agent is generally difficult to recycle, thus increasing the production cost of resolving DL-panthenolactone
In addition, chloroform extraction is mostly used for purifying L-panthenolactone, and the yield is only 12-14%, so the resolution yield of the above method is relatively low

Method used

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  • Spliting method for DL-pantoyl intenral ester
  • Spliting method for DL-pantoyl intenral ester

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0018] Embodiment 1 (resolving agent R-NH 2 purification)

[0019] Accurately weigh 285 grams of R-NH 2 The crude product (industrial pure, commercially available) is added in 474 milliliters of anhydrous toluene, 64.8 grams of glacial acetic acid are added in a 250 milliliter constant pressure dropping funnel, slowly added in the toluene, after the dropwise addition, the water bath is heated to 80 -85°C, react for 0.5 hours, transfer to a 200ml large beaker after completion, cool naturally at room temperature, and then use an ice-water bath to cool to 0-10°C for crystallization, crystallization is complete, filter, and the filtrate is used for the next batch. , the solid was directly used for the next step of recrystallization.

[0020] Put the above solid into a 1000 ml three-necked flask, then add 423 ml of toluene, heat up the water bath to dissolve it, and keep it under reflux for 0.5 hours, then transfer it to a 1000 ml flask after completion, repeat the above crystall...

Embodiment 2

[0022] Embodiment 2 (preparation of DL-panthenolactone hydrolyzate)

[0023] Add 70.5 g of DL-panthenolactone into a 1000 ml four-necked flask, measure 210 ml of 2 mol / L sodium hydroxide, pour it into the flask, install a thermometer, put the reflux condenser in the four-necked flask, and under stirring, Raise the temperature to 75-80°C and hydrolyze for 0.5 hours. Finished, measured pH value is 9-10 is advisable. Then adjust the pH value to 7.5-8 with 2 mol / L hydrochloric acid.

Embodiment 3

[0024] Embodiment 3 (resolution of DL-panthenolactone)

[0025] 61.5 g R-NH 2 Add 0.25 ml of concentrated hydrochloric acid to the resolving agent, stir to form a salt, add 480 ml of water, heat to 80-85°C in a water bath to dissolve it, add the DL-pantolactone hydrolyzate in the above example 2, and control the dropping time Not less than 1 hour, the rate of addition is 5 ml / min, stirring at 450 rpm, the temperature of the water bath is 70-75°C, after dropping, continue to stir for 1 hour, cool to room temperature, vacuum filter, and the filter cake is used to recover D - pantothenolactone and most of the resolving agent, the filtrate decompresses and recovers water, making it 1 / 3 of the original volume, after the completion, adjust 10-11 with 2 mol / liter sodium hydroxide, and use 200 ml of toluene, 250 Milliliter extraction twice, the extract toluene is used to recover a small amount of resolving agent R-NH dissolved in the filtrate 2 , the aqueous phase is adjusted to pH ...

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Abstract

The invention relates to a resolution method of DL-panthenolactone. The resolving agent used in the existing resolution method has low selectivity when resolving DL-panthenolactone, which makes the total utilization rate of DL-panthenolactone low and improves the efficiency of resolving DL-panthenolactone. Cost of production. The resolving agent used in the present invention is an organic base R-NH 2 , where R is C 15 h 15 , comprising the following steps: a) reacting the purified resolving agent with acid, adding water, heating and dissolving, adding dropwise DL-pantothenolactone hydrolyzate, resolving agent: the molar ratio of DL-pantothenolactone=0.5- 0.7:1; b) Suction filter the reaction liquid obtained in a, carry out racemization on the filter cake, recover the resolving agent, add an organic solvent to the filtrate for azeotropic dehydration, distill off the excess organic solvent for crystallization. The present invention obviously improves the selectivity of the resolving agent to D-panthenolactone, improves the total utilization rate of DL-panthenolactone, has high resolution yield, reduces the amount of resolving agent and is easy to recycle repeatedly, reducing Breakdown of the production cost of DL-panthenolactone.

Description

technical field [0001] The invention relates to a resolution method for producing D-pantothenate calcium intermediate DL-pantothenolactone. Background technique [0002] At present, most of the synthesis processes of D-calcium pantothenate adopt the method of first synthesizing DL-calcium pantothenate, and then splitting to generate D-calcium pantothenate and L-calcium pantothenate. L-calcium pantothenate is converted into DL-calcium pantothenate by catalytic racemization, which is repeatedly disassembled. converted into D-calcium pantothenate. The disadvantage of this method is that the resolution yield of L-calcium pantothenate is low, the effective utilization rate of L-calcium pantothenate is low, and the production cost is relatively high. The existing improved method is to firstly split DL-pantothenolactone, the main intermediate of DL-pantothenate calcium, with a resolving agent to obtain L-pantothenolactone and D-pantothenolactone. The acylation reaction of lactone...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07B57/00C07D307/56
Inventor 吴再红邱贵生
Owner ZHEJIANG NHU CO LTD
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