4-Diazo-2,5-cyclohexadien-l-one

In aromatic diazonium compounds containing an ionized hydroxyl group ( —O-) in the 2- or 4-position, it is necessary to consider delocalization of electrons and, therefore, two mesomeric structures (1.7a-1.7b) (see Sec. 4.2). This fact has implications for nomenclature compounds of this type are considered as quinone derivatives following IUPAC Rule C-815.3 (Exception) compounds of this class are called quinone diazides. As a specific compound 1.7a-1.7b is indexed in Chemical Abstracts as 4-diazo-2,5-cyclohexadien-l-one. If reference is made specifically to mesomeric structure 1.7b, however, it is called 4-diazoniophenolate. 

DiazopbenoL See Benzenediazooxide, Vol 2, p B58-L and 4-Diazo-2,5-Cyclohexadien-l-one in this Vol Motion itroderi vs... 

Reactivity with Diazo Oxides and Azides. Diazo oxides, e.g. 2,6-di-f0rf-butyl-4-diazo-2,5-cyclohexadiene-l-one (184, R = terr-butyl) or 2,6-diphenyl-4-diazo-2,5-cyclohexadiene-l-one (184, R = phenyl) are thermolabile and photolabile. Car-benes 185 are formed from 184 as reactive intermediates. The process proceeds in a one-step mechanism in which the carbene species reacts in the singlet state [238], The attachement of 185 to saturated hydrocarbon chains proceeds via insertion in C—H bond during processing. LDPE and PP were modified in this way [239, 240]. Poly(oxymethylene) was modified similarly. 

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