155699-37-9Relevant academic research and scientific papers
Aromatic azapentalenes: 1H- and (mesoionic) 2H-pyrrolotetrazoles. Part 2. Reaction with electrophiles
Moderhack,Decker,Holtmann
, p. 729 - 735 (2007/10/03)
Protonation, acetylation, benzoylation, carbamoylation, formylation, bromination, azo coupling, nitrosation and addition to DMAD were studied. Monosubstitution occurred as a rule (bromination excepted), the preferred site of attack being C(5) if both the 5 and 7 positions were free. A number of observations point to a slightly higher reactivity of the mesoionic isomers 2; this is consistent with AM1 calculations. 1,3-Dipolar cycloaddition behaviour of 2 towards DMAD, a conceivable process, could not be detected; only linear addition was observed. Nitroso derivatives of the series 3,4 and 8 were not isolated as such but as the ring-opened nitrile oxides 11 and 12; at elevated temperature analogous valence isomers arise also from the nitroso derivative 7e and the azo compounds 3e and 4e.
PYRROLE RING OPENING IN 5-NITROSO- AND 5-PHENYLAZO-1H-PERROLOTETRAZOLES - AN UNEXPECTED VALENCE ISOMERISM
Moderhack, Dietrich,Decker, Dirk
, p. 683 - 688 (2007/10/02)
1,6-Disubstituted 5-nitroso-1H-pyrrolotetrazoles ring open below 20 deg C to give the isomeric acrylonitrile oxides.The 5-phenylazo analogs as well as 5-nitroso derivatives having in addition an accptor group at C-7 are stable at 20 deg C, but heating with the dipolarophile DMAD leads to pyrazoles and isoxazoles.
