Table 1 ¹H and ¹³C NMR spectral data for AB023a and takanawanen C (δ in ppm and J in Hz) in DMSO-d₆

173.7

174.2

46.1

2.26 (1H, m)

45.9

2.30 (1H, m)

72.0

3.71 (1H, m)

71.8

3.74 (1H, m)

41.5

1.32 (2H, m)

41.7

1.34 (2H, m)

71.4

3.45 (1H, m)

71.4

3.44 (1H, m)

38.8

1.23 (2H, m)

38.8

1.25 (2H, m)

22.4

0.83 (1H, m), 1.71 (1H, m)

22.5

0.83 (1H, m), 1.72 (1H, m)

40.4

1.23 (2H, m)

40.1

1.25 (2H, m)

71.2

3.51 (1H, m)

71.4

3.52 (1H, m)

43.4

1.27 (2H, m)

43.6

1.29 (2H, m)

69.6

3.80 (1H, m)

69.5

3.80 (1H, m)

38.2

1.23 (2H, m)

38.3

1.25 (2H, m)

67.7

3.45 (1H, m)

67.7

3.44 (1H, m)

45.4

1.63 (1H, m)

45.4

1.62 (1H, m)

73.5

3.63 (1H, m)

74.5

3.60 (1H, m)

136.5

5.59 (1H, dd, 15.35, 8.52)

136.7

5.57 (1H, dd, 15.22, 8.66)

130.3

6.11 (1H, m)

130.4

6.08 (1H, m)

132.9–131.2

6.25 (1H. m)

132.9–131.1

6.22 (1H. m)

132.9–131.2

6.25 (1H. m)

132.9–131.1

6.22 (1H. m)

132.9–131.2

6.25 (1H. m)

132.9–131.1

6.22 (1H. m)

132.9–131.2

6.25 (1H. m)

132.9–131.1

6.22 (1H. m)

132.9–131.2

6.25 (1H. m)

132.9–131.1

6.22 (1H. m)

132.9–131.2

6.25 (1H. m)

132.9–131.1

6.22 (1H. m)

129.5

6.11 (1H, m)

129.7

6.08 (1H, m)

136.2

5.87 (1H, dd, 15.31, 6.65)

136.1

5.82 (1H, dd, 15.22, 6.87)

38.2

2.34 (1H, m)

36.0

2.45 (1H, m)^a

74.4

4.65 (1H, m)

80.1

4.59 (1H, dd, 8.60, 3.45)

13.2

1.06 (3H, d, 7.01)

13.8

1.12 (3H, d, 6.90)

10.4

0.88 (3H, d, 6.69)

10.5

0.88 (3H, d, 6.79)

15.9

1.01 (3H, d, 6.81)

15.6

1.00 (3H, d, 6.65)

18.7

1.18 (3H, d, 5.97)

28.7

1.95 (1H, m)

19.7

0.83 (3H, d, 6.96)

15.4

0.85 (3H, d, 7.04)