Tautomers Cumulative

However, from elegant labelling studies by Wentrup and coworkers on the gas-phase thermal interconversion of phenylnitrene and 2-pyridylcarbene, it became evident that an alternative and equally viable intermediate in these nitrene ring expansions is the azacycloheptatrienylidene (216) or its tautomer, the cumulated system (217) (81AHC(28)23l). 

Analysis of the deuterium isotopic shifts in the C-NMR spectrum has been particularly useful for sugar and oligosaccharide structural studies and spectral assignments (18, 151). Application of the differential isotope shift technique was used to study the tautomers of psicose, (33a-33d), in solution (Fig. 2.37a) (384). Signal assignments were made by comparison of calculated and observed cumulative isotope shifts. This method distinguished the C-1 and C-6 resonances. 

Nakagawa and co-workers (1980) reported that a serum level of 214 p,g/ml was measured 5 min after an intravenous bolus injection of 1 g of YM09330 into human volunteers (Table VIII). A serum level of 17 (jLg/ml was still present 8 hr after dosing. The serum half-life (P) was 3.4 hr. Cumulative urinary recovery after 24 hr was 84%. An additional 5% of the biologically active tautomer (34) was also recovered. 

---

See also in sourсe #XX -- [ ]

---