Release of Nitrosating Species in the Course of Reduction of Benzo-1,2,3,4-tetrazine 1,3-Dioxides

Abstract

[reaction: see text] The reduction of benzo-1,2,3,4-tetrazine 1,3-dioxides (BTDOs) 1 with Na(2)S(2)O(4) or SnCl(2) is suggested to proceed via intermediate N-nitrosobenzotriazoles 3 to afford benzotriazoles 2. The (15)N-labeling experiments exhibit that the N-3 atom of the tetrazine ring is incorporated into the nitroso group of 3 that is ultimately released into solution. It is possible that the biological activity of BTDOs is due to their ability to release nitrosating species, i.e., N-nitrosotriazol 3 or HNO(2), in the course of reduction.

Nickel‐2,2′‐Bipyridyl and Palladium‐Triphenylphosphine Complex Promoted Synthesis of New π‐Conjugated Poly(2‐hexylbenzotriazole)s and Characterization of the Polymers

“…[16] As can be seen from Schemes 1 and 2, the method shown by Scheme 1 gave 2 in higher yield. As described above, the two 1 H NMR spectra of 2, one obtained from 1,2,3-benzotriazole and the other obtained from 1,2-diamino-3,6-dibromobenzene, were identical, supporting that 2 had bromines at the 4-and 7-positions.…”

Annulated benzotetrazine 1,3-dioxides 1. [1,2,5]Oxadiazolo[3,4-f][1,2,3,4]benzotetrazine 2,4,7-and 2,4,9-trioxides

“…As ex pected, 5 the nitration occurred virtually exclusively at position 5. The structure of BTDO 2a was unam biguously confirmed by 1 H, 13 C, 14 N, and 15 N NMR spectra with complete assignment of signals (see Experi mental).…”

“…Heating without a solvent, 120-125 °C, 30 min (66%). 1 H and 13 C NMR spectra recorded at 297 K show that the product exists as a 1 : 1 mixture of two isomers 6a and 7a (Table 1). On heating to 373 K in DMSO d 6 , the signals from the isomers in the 1 H NMR spectra coalesce.…”

Synthesis and structures of pyridoannelated 1,2,3,4-tetrazine 1,3-dioxides

“…6 X ray diffraction study. Single crystals of the complex of 7 nitropyrido[2,3 e] [1,2,3,4]tetrazine 1,3 dioxide 10 with ben zene were grown from benzene. X ray diffraction data were 1.376 (7) collected on an automated Enraf Nonius CAD 4 diffractometer (MοKα radiation, graphite monochromator, θ/2θ scanning tech nique, 2θ < 52.0°).…”