11.9g. of calcium pantothenate, 6.8g. of cystamine dihydrochloride and 7.7g. of 1-hydroxylbenzotrizole were dissolved in 50ml. of pyridine and 10ml. of water, and thereafter pyridine (25ml.) solution of 10.5g. of dicyclohexylcarbodiimide was added thereto at a time, and the reaction was effected at a temperature below 10° C for 1 hour and then for 5 hours at a room temperature. Next the solvent was removed under a reduced pressure, the residue thereof was added with 50ml. of water, and the deposited crystals were removed by filtration. Pyridine left in the filtered mother liquor was completely removed azetropically with water. The residue thereof was added with 50ml. of water and after cooling, the deposited crystals were filtration removed and extracted with 20ml. of chloroform two times. The water layer was treated under a reduced pressure to remove the remaining chloroform, and thereafter like Example 1, passed through the ion exchange resin, and the flowed out liquid was concentrated under a reduced pressure and thereby colorless transparent viscous liquid of pantethine which was the objective compound was obtained. Drying was carried out by means of a vacuum dryer for one night and as a result 9.6g. of pantethine (yield rate 69.2%) was obtained.
