Table 1 ¹H NMR (600 MHz) and ¹³C NMR (150 MHz) spectral data of compounds 1–3 in DMSO-d ₆

1

169.8

–

167.6

–

168.0

–

2

–

–

–

–

–

–

3

78.5

4.72 (1H, qd, 6.4, 1.6)

80.7

4.88 (1H, qd, 6.8, 1.6)

80.9

4.87 (1H, qd, 6.8, 1.2)

4

62.3

4.66 (1H, dd, 6.8, 1.6)

63.2

4.77 (1H, dd, 5.2, 1.6)

63.6

4.67 (1H, dd, 5.6, 1.2)

5

124.7

–

125.3

–

127.0

–

6

138.3

7.64 (1H, d, 8.8)

138.3

7.66 (1H, d, 8.8)

137.1

7.45 (1H, d, 8.4)

7

117.3

6.99 (1H, d, 8.8)

117.0

7.03 (1H, d, 8.8)

116.7

6.92 (1H, d, 8.4)

8

161.1

–

160.6

–

158.8

–

9

16.6

1.45 (3H, d, 6.4)

17.4

1.16 (3H, d, 6.8)

16.7

1.16 (3H, d, 6.8)

10

62.2

5.09 (1H, d, 12.4)

62.0

5.07 (1H, d, 12.4)

17.6

2.29 (3H, s)

5.17 (1H, d, 12.4)

5.20 (1H, d, 12.4)

11

170.8

–

170.2

12

21.2

2.04 (3H, s)

20.7

2.03 (3H, s)

4a

141.3

–

138.9

–

138.6

8a

108.2

–

107.4

–

107.1

OH-4

5.70 (1H, d, 7.2)

5.96 (1H, d, 5.2)

–

5.82 (1H, d, 5.2)

OH-8

11.20 (1H, s)

11.19 (1H, s)

–

10.9 (1H, s)