Table 1

¹H NMR chemical shifts of the isomers of (R)- and (S)-[¹³C]KP glucuronides obtained by two-dimensional NMR analysis of the reaction mixtures in ²H₂O

Isomer	Glucuronide Ring ¹H NMR Signals (δ)
	(R)-[¹³C]KP Glucuronide		(S)-[¹³C]KP Glucuronide
	H1	H2	H3	H4	H5	H1	H2	H3	H4	H5
4α	5.28	3.65	3.82	4.90	4.23	5.28	3.68^1-a	3.91	4.92	4.20
4β	4.66	3.35	3.62	4.92	3.88	4.67	3.38	3.71	4.94	3.84
3α	5.27	3.73	5.20	3.58	4.14	5.23	3.65^1-a	5.20	3.67	4.17
3β	4.73	3.44	5.01	3.60^1-a	3.79	4.71	3.36	5.01	3.69	3.82
2α	5.28	4.77	3.90	3.60^1-a	4.09	5.39	4.75^1-a	3.88	3.58	4.13
2β	4.62	4.74	3.68	3.60^1-a	3.71	—^1-b	4.74^1-a	—^1-c	—^1-c	—^1-c

↵1-a Although the coupling pattern is obscured because of the complexity of the spectra, the chemical shift is determined based on the correlation signals.
↵1-b The signal is presumed to be concealed behind the H²HO signal.
↵1-c The signal cannot be assigned because of the crowded spectrum.