Picryl azide

The cycloaddition of picryl azide with phenoxyallene took place at the C1-C2 double bond of the allene exclusively to give the triazoline intermediate 97 [89]. This intermediate underwent a facile Claisen rearrangement to yield cyclohexadienone 98, which rapidly tautomerized to phenol 99. 

Dinitrobenzofuroxan (DNBF) (68) has been prepared from the nitration of benzofuroxan (69) with mixed acid," and by treating picryl chloride (67) with sodium azide and heating the resulting picryl azide (70) in an inert solvent." " ... 

Picric acid (2,4,6-Trinitrophenol), 2118 Picryl azide, 2092 1-Picryl-l,2,3-triazole, 2893... 

It was prepd from o-phenetidine and picryl chloride (Ref 2) or picryl azide (Ref 3)... 

Nitrones, picryl azide, tetracyanooxirane, fulminic acid (HCNO), nitrile oxides,65 and nitrile imines66 are also capable of trapping the bicyclo[4.2.0]octa-2,4,7-trienc system. These cycloadditions open up synthetic possibilities to cyclobutane-condensed heterocyclic systems (e.g., 13). 

The organic derivatives of hydrazoic acid which contain an aromatic ring with nitro groups comprise an important group of initiators. Picryl azide (VII), m.p. 89-90°C is a typical example. It has been prepared both by the action of nitrous acid on trinitrophenylhydrazine (Purgotti [154], Schrader [155] and Korczynski [156]) and by the action of sodium azide on picryl chloride. Rathsburg [157] suggested... 

Azi do-2,4,6-trinitrobenzene (Tfinitropheny I Azide or Picryl Azide). See under Benzene and Beil 5, 279, (144) [2091... 

Vinyl ethyl ether Picryl azide CHCh 11.9 -30.3... 

Analogous methyl azidoformate forms with norbornene a thermal unstable triazoline.251 The decomposition products are 40% aziridine and 55% imide. Furthermore it has been observed that the rate of nitrogen evolution of the triazoline from methyl azidoformate increases threefold when triglyme and 20-fold when dimethyl sulfoxide are substituted for 1,1-diphenylethane as solvents. This fact supports a betaine intermediate in the thermal decomposition reaction. The triazoline from 2,4-dinitrophenyl azide and norbornene could just be isolated, but from picryl azide only the aziridine was obtained.252-254 Nevertheless, the high negative value of the activation entropy (—33.4 eu) indicates a similar cyclic transition state for both reactions. 

Azo derivatives of indolizines are readily prepared since the arenediazonium ion is a good electrophile. Compounds of this type are sometimes used as dyes (73AC(R)95>. Another method of preparing azobisindolizines is by reaction of indolizines with tosyl or picryl azides thus compound (33) has been obtained from 2-methylindolizine by this route. Redox characteristics of such compounds have been studied (71LA(752)182, 71LA(752)196). 

Another method of preparing azobisindolizines is by reaction with tosyl or picryl azide.191-193 2-Methylindolizine is converted into the 3,3 -bisazo compound after 2 minutes. The product yields the radical ion 130 (detected by EPR) when treated with 1 mole of silver perchlorate.194,195 The redox characteristics of such compounds have been studied by Hiinig and co-workers.196,197 In view of the instability of aminoindolizines, they have not been used to prepare diazonium salts. 1-Nitrosoindolizines, however, yield diazonium nitrates in good yield when treated with dry nitric oxide.182,198 The products are stable both in... 

Alkenylsilanes react with silyl azide and other organic azides to give bissilylenamines and silylaziridines, respectively, via unstable triazoline intermediates.78 Heating trimethylsilyl azide with cyclohexene or vinyltrieth-ylsilane for 10 days affords a modest yield of the respective aziridine,178 but with carefully purified trimethylsilyl azide, even after 2 weeks of reflux, no olefin consumption is indicated.104 Unstable triazoline intermediates are also formed from the reaction of cyanogen azide,808 picryl azide,29 and arylsulfonyl azides808 with unactivated olefinic bonds. 

Phenylenebis(azidomethylidyne)]bis(propanedinitrile), 3616 /-Phenyl-/-(p-toluenesulfonyloxy)-(2-azido-2-phenyl)vinyliodine(III), 3815 Picryl azide, 2085... 

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