Table 2: The configurations of C-2 and C-5 centers of major and minor diastereomers.

CompoundsDiastereomer ratio, %Configurations of C-2 and C-5
Major stereoisomerMinor stereoisomer

2a54 : 462S, 5S or 2R, 5R2S, 5R or 2R, 5S
2b60 : 402S, 5R or 2R, 5S2S, 5S or 2R, 5R
2c53 : 472S, 5R or 2R, 5S2S, 5S or 2R, 5R
2d80 : 202S, 5S or 2R, 5R2S, 5R or 2R, 5S
2e73 : 272S, 5R or 2R, 5S2S, 5S or 2R, 5R
2f52 : 482S, 5R or 2R, 5S2S, 5S or 2R, 5R