Compound

[α]D25 in MeOH

mp., ˚C

Yield, %

4a

?48.6, c 1.30

189 - 191

66

4b

?76.5, c 1.37

165 - 168

58

4c

?84.2, c 1.15

122 - 125

50

4d

?95.7, c 1.10

184 - 186

65

4e

?122.8, c 1.20

162 - 164

60

4f

?80.1, c 1.00

132 - 134

54

4g

+13.7, c 1.00

120 - 123

55

4h

+22.4, c 1.00

202 - 204

58

4i

+28.7, c 1.10

148 - 151

65