Table 1.

1H NMR data of premithramycins A1 to A4 in d6-acetonea

PositionA1b,cA2c,dA3e,fA4f,g
2-H4.75 d (11.5)
3-H2.77 tdd (11.5, 3.5, 2)
4-H4.10 d (11)4.08 s brh 4.04 s brh a: 2.95i
e: 2.62 dd (16.5, 3.5)
4-OMe3.53 s3.52 s3.52 s
4a-H3.11 ddd (11, 4, 3)3.13 ddd (11, 4, 3)3.12 ddd (11, 4, 3)
5-Ha: 3.88 ddd (16.5, 4, 1.5)a: 3.85 ddd (16.5, 4, 1)a: 3.79 ddd (16.5, 4, 1)6.64 s
e: 3.04 dd (16.5, 3)e: 3.06 dd (16.5, 3)e: 3.05 dd (16.5, 3)
6-H6.98 d (1.5)6.93 d (1)6.93 d (1)
7-H6.65 d (2)6.70 s6.71 s
7-Me2.14 s
9-H6.42 d (2)
9-CH3 2.15 s2.16 s
10-H6.72 s
1′-H4.84 d (2)
1′-OMe3.42 s
2′-H3 2.60 s2.60 s2.59 s
3′-H4.26 d (2.5)
4′-H4.26 mi
5′-H3 1.25 d (6)
1A-H4.91 dd (9.5, 2)4.89 dd (9.5, 2)4.88 dd (9.5, 2)5.10 dd (10, 2)
2A-Ha 1.52 ddd (12, 12, 9.5)1.56 ddd (12, 12, 9.5)1.55 ddd (12, 12, 9.5)1.60 ddd (12, 12, 10)
2A-He 2.49 ddd (12, 5, 2)2.54 ddd (12, 5, 2)2.55 m (broad)2.50 ddd (12, 5, 2)
3A-H3.51 ddd (12, 9, 5)i 3.55 ddd (12, 9, 5)i 3.55 ddd (12, 8.5, 5)i 3.68 mi
4A-H2.90 dd (9, 9)2.90 dd (9, 9)2.90 dd (9, 8.5)j 2.98 dd (9, 9)
5A-H3.30 dq (9, 6)3.29 dq (9, 6)3.29 dq (9, 6)3.29 dq (9, 6)
6A-H3 1.24 d (6)1.25 d (6)1.24 d (6)1.29 d (6)
1B-H4.60 dd (10, 2)4.62 dd (10, 2)4.69 dd (10, 2)
2B-Ha 1.70 ddd (12, 12, 10)1.74 ddd (12, 12, 10)1.78 ddd (12, 12, 10)
2B-He 1.88 ddd (12, 5, 2)1.90 ddd (12, 4.5, 2)1.94 mk
3B-H3.77 ddd (12, 5, 3)3.86 ddd (12, 4.5, 3)3.89 ddd (12, 4.5, 3)
4B-H3.49 s3.69 s3.72 s (broad)
5B-H3.64 q (6.5)3.67 q (6.5)3.71 qi
6B-H3 1.26 d (6.5)1.26 d (6.5)1.28 d (6.5)
1C-H4.94 dd (9.5, 2)4.96 dd (9.5, 2)
2C-Ha 1.52 dd (13.5, 9.5)1.54 dd (13.5, 9.5)
2C-He 1.86 dd (13.5, 2)1.88 dd (13.5, 2)
3C-Me1.20 s1.21 s
4C-H2.91 d (9.5)j 2.93 d (9.5)
5C-H3.62 dq (9.5, 6)3.64 dq (9.5, 6)
6C-H3 1.2 d (6)1.21 d (6)
  • a S in parts per million relative to trimethylsilyl (J in hertzes).

  • b OH signals not observed except one at δ 9.56.

  • c At 300 MHz.

  • d OH signals: δ 4.59, 9.50, 9.90, and 14.9 (all broad).

  • e OH signals: δ 3.20, 3.39, 4.58, 9.44, and 9.91 (all broad).

  • f At 500 MHz.

  • g OH signals: δ 9.91 and 16.18 (broad).

  • h After exchange with D2O: d (10).

  • i Partially obscured.

  • j Partially obscured by water; fully visible only after D2O exchange.

  • k Broad signal; no couplings visible.