Synthesis of D-panthenol

Guanidine D,L-pantoate was synthesized from D,L-pantolactone,guanidine carbonate and calcium hydroxide in a yield of 91.6%.Guanidine D-pantoate and Guanidine L-pantoate were separated from guanidine D,L-pantoate in methanol.Guanidine D-pantoate was hydrolyzed with sulfuric acid to D-pantolactone with a yield of 92.3%.D-Panthenol was synthesized from D-pantolactone and 3-aminopropanol with a yield of close to 100%.Guanidine L-pantoate was racemised to D,L-pantolactone with a yield of 86.5%.The resolution agent of guanidine can be reused.The structure of the product was identified by IR and elementary analysis.