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ChemicalBook CAS DataBase List DL-Pantolactone
79-50-5

DL-Pantolactone synthesis

9synthesis methods
-

Yield:79-50-5 98.3%

Reaction Conditions:

with sulfuric acid at 80 - 85; for 3 h;Temperature;

Steps:

1 Example 1: Preparation of D,L-pantolactone
Add to a 250 ml four-necked flask19.0 g (0.1 mol) of 40 wt% glyoxylic acid,0.5 g of triethylamine,A mixture of 7.0 g (0.1 mol) of isobutyraldehyde was added dropwise between 20 and 25 ° C,Drop finished,25 to 30 ° C for 3 hours.The resulting reaction liquid was transferred to a 250 ml stainless steel autoclave,30 g of 1,2-dichloroethane,0.2 g of 5% palladium on carbon catalyst,Access to hydrogen,Keep at 2-3 atmospheres,20-25 catalytic hydrogenation reaction was stirred for 4 hours.filter,Recovery catalyst. 0.3 g of 75% sulfuric acid was added to the filtrate (5.71% of isobutyraldehyde after purification)80 ~ 85 reaction 3 hours;Reaction is completed,Cooling to 15 ~ 20 ,Layered,The aqueous layer was extracted with 1,2-dichloroethane,Each time 20 grams,Combine organic phase,10 g 1.0%Aqueous solution of sodium carbonate,10 g of saturated aqueous sodium chloride solution,After the organic phase was distilled to recover 1,2-dichloroethane,Vacuum distillation,To give 12.8 g of a colorless transparent liquid D, L-pantolactone,GC purity 99.9%The yield was 98.3%.

References:

Xinfa Pharmaceutical Co., Ltd.;Qi, Yuxin;Wang, Tao;Wang, Haitao;Ju, Lizhu;Li, Xinfa CN106008413, 2016, A Location in patent:Paragraph 0036; 0045-0052

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