Table 1 ¹H NMR data of compounds 1–5 (δ_H in ppm, J in Hz)

2

4.86, partially overlapped

5.05, m

–

5.00, m

5.02, m

3

3.07, dd (15.0, 8.5)

2.82, dd (15.0, 7.5)

3.15, dd (15.0, 8.5)

2.94, dd (15.0, 8.5)

6.16, s

3.12, dd (15.0, 8.0)

2.88, dd (15.0, 8.5)

3.09, dd (15.0, 8.5)

2.87, dd (15.0, 8.5)

4

6.67, s

6.87, s

6.82, s

6.74, d (8.0)

6.58, d (8.0)

5

–

–

–

6.38, d (8.0)

6.36, d (8.0)

7

–

6.39, s

6.83, s

–

–

2′

7.19, d (8.5)

–

7.10, d (8.5)

7.18, d (8.5)

7.17, d (8.5)

3′

6.86, d (8.5)

6.48, d (2.5)

6.74, d (8.5)

6.85, d (8.5)

6.85, d (8.5)

5′

6.86, d (8.5)

6.43, dd (8.0, 2.5)

6.74, d (8.5)

6.85, d (8.5)

6.85, d (8.5)

6′

7.19, d (8.5)

6.98, d (8.0)

7.10, d (8.5)

7.18, d (8.5)

7.17, d (8.5)

7′

3.02, dd (14.0, 7.0)

2.84, dd (14.0, 6.5)

3.07, dd (15.0, 3.5)

3.01, dd (15.0, 7.0)

3.91, s

3.16, dd (14.0, 6.0)

2.90, dd (14.0, 6.0)

3.13, dd (14.0, 6.0)

2.90, dd (14.0, 6.0)

5-Me

2.12, s

2.10, s

–

–

–

7-Me

2.05, s

–

–

–

–

4′-OMe

3.78, s

3.75, s

–

3.79, s

3.78, s

6-OMe

–

3.76, s

–

3.82, s

–

7-OMe

–

–

–

3.93, s

–

-OCH₂O-

–

–

–

–

5.90, s