Table 2 Essential NMR data for the identification of chrozophoridin.

1H and 13C chemical shifts of the blue dye present in C. tinctoria fruits, determined in DMSO-d6:D2O (9:1).

Positionδ 1Η (ppm); J (Hz)δ 13C (ppm)*
A ring
  1-N-CH33.12; s27.4/27.5
  2 C═O164.0/163.7
  388.5/88.4
  4156.0/156.1
  4-OCH33.71; 3.78; s59.2/59.4
  5122.0/122.3
  6159.0/158.8
B ring
  7-N-CH33.12; s27.3/27.5
  8 C═O161.7/161.6
  9128.4/127.7
  10161.1/161.0
  10-OCH33.75; 3.77; s60.8/61.0
  11 C═O172.6/172.3
  12 C=O157.0/156.9
Glucose moiety
  1′4.32; d, 7.7/4.20; d, 7.5108.3/108.7
  2′3.13;74.1/74.1
  3′3.10;77.4/77.5
  4′2.90;75.0/75.0
  5′3.16;76.9/76.9
  6a′3.45;61.3/61.5
  6b′3.63;61.3/61.5

*The carbon signals are duplicated, which indicates that at least two isomers are present.

†Unresolved (superposition).