Table 1 ¹H and ¹³C NMR data of compounds 1 and 2 (δ in ppm, data obtained in CDCl₃, 500 MHz)

1

161.2, C

161.5, C

3

152.9, C

152.6, C

4

102.3, CH

6.35, s

102.6, CH

6.36, s

4a

126.0, C

131.2, C

5

135.0, C

133.3, C

6

116.5, CH

6.90, d, 2.2

131.8, CH

7.36, d, 2.2

7

160.8, C

138.2, C

7-OMe

56.0, C

3.80, s

7-CH₃

23.9, CH₃

2.35, s

8

112.3, CH

7.63, d, 2.2

128.8, CH

7.67, d, 2.2

8a

130.6, C

128.0, C

9

47.3, CH₂

3.63, s

47.1, CH₂

3.62, s

10

203.3, C

203.5, C

11

30.0, CH₃

2.15, s

30.2, CH₃

2.15, s

12

63.6, CH₂

4.64, s

63.0, CH₂

4.63, s

12-OH

4.96, br s

4.97, br s