Table 1.

Comparison of ¹³C NMR chemical shifts of 15R- and 15S-PGF_2α from their 3:4 mixture in CDCl₃ solution

PGF2α	C-1	C-2	C-3	C-4	C-5	C-6	C-7	C-8	C-9	C-10
15R	177.05	32.7	24.45	26.11	129.59	129.08	24.99	50.99	72.63	42.96
15S	177.37	32.91	24.45	26.24	129.58	129.13	25.22	50.20	72.49	42.69
15R − 15S	−0.32	−0.21	0	−0.13	0.01	−0.05	−0.23	0.79	0.14	0.27
	C-11	C-12	C-13	C-14	C-15	C-16	C-17	C-18	C-19	C-20
15R	77.87	55.65	132.4	134.59	72.96	37.05	25.13	31.7	22.61	14.03
15S	77.61	55.34	132.61	134.95	73.13	36.87	25.22	31.7	22.61	14.03
15R − 15S	0.26	0.31	−0.21	−0.36	−0.17	0.18	−0.09	0	0	0

A comparison of the chemical shifts from separate measurements cannot be taken as decisive because of very strong solvent and concentration effects in the ¹³C NMR spectra of prostaglandins. These dilution effects account for the slight differences between our observations and an earlier report of ¹³C NMR differences for 15R- and 15S-PGF_2α (20).