A. Lyčka, Štěpán Frebort, N. Almonasy
Jun 30, 2008
Citations
0
Influential Citations
9
Citations
Journal
Tetrahedron Letters
Abstract
Abstract Dimethyl dihydro-1,2,4,5-tetrazine-3,6-dicarboxylate can exist either in 1,2- or 1,4-dihydro tautomeric forms. The 15 N NMR spectra of dimethyl dihydro-1,2,4,5-tetrazine-3,6-dicarboxylate were measured at the 15 N natural abundance level as well as in 15 N doubly labelled selectively and in 15 N completely labelled compounds (20% 15 N). The J ( 15 N, 15 N) value was determined in 15 N completely labelled compounds (20% 15 N) using 1D 15 N INADEQUATE and was found to be 12.2 ± 0.2 Hz in deuteriochloroform, acetonitrile- d 3 , DMSO- d 6 and CD 3 OH. Very similar 15 N chemical shifts and 1 J ( 15 N, 1 H) values were also observed in all the solvents. This indicates that compound 1 exists completely in the 1,4-dihydro tautomeric form (i.e., as dimethyl 1,4-dihydro-1,2,4,5-tetrazine-3,6-dicarboxylate) in all the solvents tested.