Spectral assignments for the aldose reductase inhibitor 4(S)‐2,3‐dihydro‐6‐fluoro‐2(R)‐methylspiro[chroman‐4,4′‐imidazoline]‐2′,5′‐dione and its synthetic intermediates

The 1H and 13C NMR chemical shifts of the aldose reductase inhibitor 4(S)-2,3-dihydro-6-fluoro-2(R)-methylspiro[chroman-4,4'-imidazoline]-2',5'-dione, methylsorbinil, and its seven synthetic intermediates, have been completely assigned on the basis of DEPT, COSY, g-HSQC and g-HMBC. All C--F coupling constants from one-bond to four-bond in the 13C NMR spectra and H--F and H--H coupling constants from three-bond to four-bond in 1H spectra were obtained.