反应详情

Next, (R)-(−)-2-phenylpropionyl chloride prepared from (R)-(−)-2-phenylpropionic acid (4.65 g, 3.10 mmol) and thionyl chloride (30 mL), and N-[2-(3-acetyl-5-amino-2-phenyl-2,3-dihydro-1,3,4-thiadiazol-2-yl)ethyl]methane-sulfonamide obtained above were treated in pyridine (5.0 mL, 61.8 mmol) in the same manner as that in Step 1 of Example 20, and the resultant was purified by silica gel column chromatography (chloroform/n-hexane/ethyl acetate/methanol=20/3/2/1) to give one diastereomer of N-[4-acetyl-5-(2-methanesulfonylaminoethyl)-5-phenyl-4,5-dihydro-1,3,4-thiadiazol-2-yl]-2-phenylpropanamide (0.75 g, 12%) as a fraction eluted first, and another diastereomer of N-[4-acetyl-5-(2-methane-sulfonylaminoethyl)-5-phenyl-4,5-dihydro-1,3,4-thiadiazol-2-yl]-2-phenylpropanamide (0.82 g, 13%) as a fraction eluted later.

1. customobtained
2. customthe resultant was purified by silica gel column chromatography (chloroform/n-hexane/ethyl acetate/methanol=20/3/2/1)