38693-83-3Relevant academic research and scientific papers
3-pyridazinylnitrenes and 2-pyrimidinylnitrenes
Torker, Sebastian,Kvaskoff, David,Wentrup, Curt
, p. 1758 - 1770 (2014/03/21)
Mild flash vacuum thermolysis of tetrazolo[1,5-b]pyridazines 8T generates small amounts of 3-azidopyridazines 8A (8aA, IR 2145, 2118 cm-1; 8bA, 2142 cm-1). Photolysis of the tetrazoles/azides 8T/8A in Ar matrix generates 3-pyridazinylnitrenes 9, detected by ESR spectroscopy (9a: D/hc = 1.006; E/hc = 0.003 cm-1). Cyanovinylcarbenes 11, derived from 4-diazobut-2-enenitriles 10, are also detected by ESR spectroscopy (11a: D/hc = 0.362; E/hc = 0.021 cm-1). Carbenes 11 rearrange to cyanoallenes 12 and 3-cyanocyclopropenes 13. Triazacycloheptatetraenes 20 were not observed in the photolyses of 8. Photolysis of tetrazolo[1,5-a]pyrimidines/2- azidopyridmidines 18T/18A in Ar matrices at 254 nm yields 2-pyrimidinylnitrenes 19, observable by ESR, UV, and IR spectroscopy (19a: ESR: D/hc = 1.217; E/hc = 0.0052 cm-1). Excellent agreement with the calculated IR spectrum identifies the 1,2,4-triazacyclohepta-1,2,4,6-tetraenes 20 (20a, 1969 cm -1; 20b, 1979 cm-1). Compounds 20 undergo photochemical ring-opening to 1-isocyano-3-diazopropenes 23. Further irradiation also causes Type II ring-opening of pyrimidinylnitrenes 19 to 2-(cyanimino)vinylnitrenes 21 (21a: D/hc = 0.875; E/hc = 0.00 cm-1), isomerization to cyaniminoketenimine 25 (2044 cm-1), and cyclization to 1-cyanopyrazoles 22. The reaction mechanisms are discussed and supported by DFT calculations on key intermediates and pathways. There is no evidence for the interconversion of 3-pyridazinylnitrenes 9 and 2-pyrimidinylnitrenes 19.
Matrix isolation photolysis study of tetrazolo[1,5-b]pyridazine
Hill, Brian T.,Platz, Matthew S.
, p. 1051 - 1058 (2007/10/03)
Photolysis (254 nm) of tetrazolo[1,5-b]pyridazine (TP) in 2-methyltetrahydrofuran at 7 K does not produce electron spin resonance absorptions that are usually characteristic of a triplet nitrene. The UV-vis spectrum formed upon photolysis of TP in 2-methyltetrahydrofuran at 77 K is also consistent with the lack of formation of triplet 3-pyridazylnitrene. Photolysis (254 nm) of tetrazolo[1,5-b]pyridazine (TP), i.e., 3-azidopyridazine in an Ar matrix at 16 K produces an infrared spectrum consistent with the formation of Z-cis-1-cyano-3-diazopropene, 1,3,7-triazacyclohepta-1,2,4,6-tetraene, and 3-cyanocyclopropene whose spectra were adequately simulated by density functional theory with a 6-31G* basis set. There is no spectral evidence to support the formation of triplet 3-pyridazylnitrene. Cyclization of the singlet pyridazylnitrene is observed in minute amounts to ultimately produce the ring-expanded 1,3,7-triazacyclohepta-1,2,4,6-tetraene (νN=C=N = 1981 cm-1). This observation indicates that the earlier vibrational assignment to 1,3,7-triazacyclohepta-1,2,4,6-tetraene in the 2-pyrimidylnitrene system (νN=C=N = 2045 cm-1) is in error, and should be attributed to the 1972 cm-1 vibrational absorption in the previously recorded spectrum.
Cycloaddition of 3-Cyanocyclopropene with Anthracenes
Saito, Katsuhiro,Isobe, Satoru,Ito, Kazuaki,Kagabu, Shinzo,Takahashi, Kensuke
, p. 1541 - 1542 (2007/10/02)
The thermal reactions of 3-cyanocyclopropene with 9-substituted anthracenes afforded cycloadducts.The relative rate ratio of the reaction correlated well with the substituent constants.
