Table 1 ¹ H and ¹³ C NMR spectroscopic data of compound 5 (600 MHz, δ in ppm)

5.07

(s)

76.3

3

5.34

(m)

67.8

4α

2.65

(dd, J = 17.6, 2.4 Hz)

25.6

4β

2.92

(dd, J = 17.6, 4.9 Hz)

25.6

4a

97.2

5

156.6*

6

5.94

(d, J = 2.4 Hz)

95.6

7

156.5*

8

5.79

(d, J = 2.4 Hz)

94.3

8a

155.5

1'

128.6

2',6'

7.25

(d, J = 8.6 Hz)

127.8

3',5'

6.7

(d, J = 8.6 Hz)

114.8

4'

156.9

C = O

166.1

α

6.25

(d, J = 15.8 Hz)

113.6

β

7.38

(d, J = 15.8 Hz)

145.3

1"

124.6

2",6"

7.5

(d, J = 8.6 Hz)

130.5

3",5"

6.72

(d, J = 8.6 Hz)

115.8

4"

160.3