A N-15 NMR study of tautomerism in dimethyl dihydro-1,2,4,5-tetrazine-3,6-dicarboxylate

作者：Lycka Antonin^*; Frebort Stepan; Almonasy Numan

来源：Tetrahedron Letters, 2008, 49(27): 4213-4215.

DOI：10.1016/j.tetlet.2008.04.161

• dihydro-1,2,4,5-tetrazine
• N-15 NMR
• (n)J(N-15,N-15)
• tautomerism

Dimethyl dihydro-1,2,4,5-tetrazine-3,6-dicarboxylate can exist either in 1,2- or 1,4-dihydro tautomeric forms. The N-15 NMR spectra of dimethyl dihydro-1,2,4,5-tetrazine-3,6-dicarboxylate were measured at the N-15 natural abundance level as well as in N-15 doubly labelled selectively and in N-15 completely labelled compounds (20% N-15). The J(N-15, N-15) value was determined in N-15 completely labelled compounds (20% N-15) using 1D N-15 INADEQUATE and was found to be 12.2 +/- 0.2 Hz in deuteriochloroform, acetonitrile-d(3), DMSO-d(6) and CD3OH. Very similar N-15 chemical shifts and (1)J(N-15,H-1) values were also observed in all the solvents. This indicates that compound I 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.

• 出版日期2008-6-30