155699-45-9

Upstream product

• 70-11-1 α-bromoacetophenone 
• 77-78-1 dimethyl sulfate 
• 350802-22-1 [1-(2-oxo-2-phenyl-ethyl)-1H-tetrazol-5-yl]-acetic acid methyl ester 

Downstream Products

• 155699-34-6 (1-Methyl-6-phenyl-1H-pyrrolotetrazol-5-yl)-phenyl-diazene 
• 155699-37-9 (Z)-3-(1-Methyl-1H-tetrazol-5-yl)-2-phenyl-acrylonitrile N-oxide 
• 155699-54-0 1-Methyl-5-nitroso-6-phenyl-1H-pyrrolotetrazole-7-carboxylic acid methyl ester 
• 155699-50-6 1-Methyl-6-phenyl-1H-pyrrolotetrazole 

Relevant academic research and scientific papers

Aromatic azapentalenes: 1H- and (mesoionic) 2H-pyrrolotetrazoles. Part 1. Synthesis and spectral characteristics

Two separate series of the title systems have been prepared by cyclisation of tetrazolium salts having acylmethyl functions attached to both the ring carbon and the adjacent nitrogen atom (3, 4): (i) working in an acetate buffer led to 7-acyl derivatives (5, 6; Scheme 3), and (ii) treatment with anhydride-base gave 5,7-diacyl compounds by a deviating ring closure mechanism (11, 12; Scheme 4). These materials could be defunctionalised to afford pyrrolotetrazoles (7, 8) which were earlier approached in vain from the respective 5-methyltetrazolium salts (Tschitschibabin reaction). Regarding characterisation data, attention is drawn to the conspicuous spectroscopic differences between the 1H- and the 2H-system. 2H-Pyrrolotetrazoles (6, 8, 12) represent a novel class of Ramsden's 'type C' heteropentalene mesoions.

PYRROLE RING OPENING IN 5-NITROSO- AND 5-PHENYLAZO-1H-PERROLOTETRAZOLES - AN UNEXPECTED VALENCE ISOMERISM

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.