Azide aromatic

Gilbert and Voreck synthesized hexakis(azidomethyl)benzene (HAB) (45) from the reaction of hexakis(bromomethyl)benzene (44) with sodium azide in DMF. This azide has been comprehensively characterized for physical, thermochemical and explosive properties and stability. HAB is a thermally and hydrolytically stable solid and not highly sensitive to shock, friction or electrostatic charge but is sensitive to some types of impact. It shows preliminary 

No peroxide has found practical use as an explosive, a consequence of the weak oxygen-oxygen bond leading to poor thermal and chemical stability and a high sensitivity to impact. Hexamethylenetriperoxidediamine (HMTD) (46) is synthesized from the reaction of hexamine with 30 % hydrogen peroxide in the presence of citric acid. HMTD is a more powerful initiating explosive than mercury fulminate but its poor thermal and chemical stability prevents its use in detonators. 

Another interesting dialkylperoxide explosive, which probably has the structure of (47), is synthesized by the addition of hydrogen peroxide and nitric acid to a solution of urea and formaldehyde.  

Some ketone-derived peroxides have explosive properties, of which the most interesting are obtained from acetone. Four acetone-derived peroxides have been synthesized. Acetone peroxide dimer (48) is obtained in 94 % yield by treating acetone with a slight excess of 86 % hydrogen peroxide in acetonitrile in the presence of concentrated sulfuric acid at subambient temperature. The reaction of acetone with potassium persulfate in dilute sulfuric acid also yields acetone peroxide dimer (48). Acetone peroxide trimer (49), also known as triacetone triperoxide (TATP), has been obtained as a by-product of these reactions or by the addition of 

Molecules such as TATP (49) possess explosive strength similar to TNT. Furthermore, TATP is extremely sensitive to heat and vibrational shock and can be ignited with an open flame or small electrical discharge i.e. does not need a primer unlike conventional explosives. 

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DUTT - WORMALL Azide formation Synthesis of aromatic azides from anilines via diazonium salts. 

Extensions of 1,3-dipolar additions of aromatic azides (720,721) to other enamines (636), and particularly to the enamine tautomer of SchilTs bases, were explored (722,723). Further nitrone additions were reported (724,725) and a double nitrile oxide added to an endiamine (647). Cyanogen azide and enamines gave cyanoamidines through rearrangement (726). 

The reaction of l-morpholylbut-l-en-3-yne with aromatic azides gives 1-aryl-4-ethynyl-5-iV-morpholino-A -triazolines (164), which readily eliminate morpholine to form l-aryl-4-ethynyltriazole (165) during chromatographic purification (83DIS). 

The interaction of l-methoxybut-l-en-3-yne with aromatic azides proceeds at the unsubstituted acetylenic bond to furnish two structural isomeric triazoles, 166 and 167 (4 1 ratio), due to the different 1,3-dipole orientations (83DIS). 

This approach has been recently extended to the reduction of aromatic azides using EtsSiH, which afford anilinosilanes and hence the corresponding anilines in virtually quantitative yields (Reaction 38). The EtsSi radical adds to the aromatic azido group to give an N-silylarylaminyl radical presumably through loss of nitrogen. Eventual reduction of the silylarylaminyl radical by ferf-dodecanethiol affords N-silylaniline 31, the hydrolytic precursors of the final anilines. 

As mentioned in Section VIII.F (Scheme 12), 1 reacts with aromatic azides to give [3 + 2] cycloadducts 47. Sulfonyl and phosphoryl azides, however, react with 1 in a different manner to afford five-membered ring compounds (Eqs. 23 and 24).79... 

The Sundberg indole synthesis using aromatic azides as precursors of nitrenes has been used in synthesis of various indoles. Some kinds of aryl azides are readily prepared by SNAr reaction of aromatic nitro compounds with an azide ion. For example, 2,4,6-trinitrotoluene (TNT) can be converted into 2-aryl-4,6-dinitroindole, as shown in Eq. 10.60.83... 

A photosensitive composition, consisting of an aromatic azide compound (4,4 -diazidodi-phenyl methane) and a resin matrix (poly (styrene-co-maleic acid half ester)), has been developed and evaluated as a negative deep UV resist for high resolution KrF excimer laser lithography. Solubility of this resist in aqueous alkaline developer decreases upon exposure to KrF excimer laser irradiation. The alkaline developer removes the unexposed areas of this resist. 

It is known that aromatic azides are photodecomposed to give active nitrenes as the transient species, which react with the environmental binder polymers to crosslink them. However, the mechanism of these photocrosslinking polymers has not been studied in detail. L.S.Efros et al. have proposed that the rubber polymer is crosslinkes in such a way that the aromatic nitrene inserts into an unsaturated bond of the polymer to give an aziridine ring. The experimental evidence for this, however, has not been given (8). 

In the present experiment, we have studied the mechanism of photocrosslinking of 1,2-polybutadiene by aromatic azide, based on the reaction of aromatic nitrene with unsaturated hydrocarbon monomeric compounds. 

PE, RIE and IM resistances for an extensive list of commercial photoresists are included as well for comparison with the vinyl systems and amongst themselves. Although the exact com-osition of these systems is not public information, the generic type of base resin or polymer binder is generally known. In addition, the photoactive components are all known to be aromatic azides or azo-compounds. 

Diazophenols and aromatic azides are much more sensitive to impact than polynitroaromatics. A similar trend is observed for polynitroaromatics containing nitramine groups. The initial reaction on impact of this class is believed to be cleavage of the -N-N02 bond. 

The asymmetric and symmetric vibrations of methyl azide have frequencies of 2141 cm-1 and 1351 cm-1 respectively (Eyster and Gillette [30]). For a number of aliphatic and aromatic azides Lieber et al. [31] found the figures 2114-2083 cm-1 for asymmetric vibrations and 1297-1256 cm-1 for symmetric ones. Among the other authors who have examined organic azides the investigations of Boyer [32] and Evans and Yoffe [33] are noteworthy. 

The same reaction also occurs at a lower temperature. 0.665 % of the substance decomposed at 20°C to form benzotrifuroxane in 3 years 2.43% at 35°C in one year 0.65% at 50°C in 10 days and at 100°C the substance underwent complete change in 14 hr. This decomposition is not, however, autocatalytic. This reaction — the formation of furoxane derivatives from aromatic azides with nitro group in the or/Ao-position — is of a general character (Boyer al. [160]). Despite the ease with which it decomposes trinitrotriazidobenzene has not been rejected for use as an initiator. In some countries large scale experiments are in progress to examine the possibilities of developing its practical application. 

An extensive review of the chemistry of aliphatic and aromatic azides is given by Boyer and Canter [167] and Gray [168]. Organic azides are subject to various reactions such as the Bergmann degradation and the synthesis of peptides, the well known Curtius rearrangement, the Darapsky synthesis of a-aminoacids [169], for synthesis of triazoles [170], tetrazoles ( Schmidt reaction ) [169] and [171] etc. These reactions lie beyond the scope of the present book. 

Reduction of aromatic azides. Aromatic azides can be reduced to anilines by this reagent in CHCl3 at 25°. The rate is accelerated by electron-withdrawing substituents but is reduced by electron-attracting groups. Even so, the presence of an azide group does not interfere with use of the reagent for reduction-of acid chlorides to aldehydes. 

Addition of Aromatic Azides to Enamines, Aldimines, and Ketimines... 

The reaction of azides with ethoxyacetylene (98) has been studied by Italian authors. With aliphatic and aromatic azides, the expected 1-substituted 5-ethoxy-l,2,3-triazoles (99) are obtained.310-311 Sulfonyl azides, on the other hand, react with ethoxyacetylene at room temperature to yield no triazoles but the valence tautomeric diazo compounds (100).312-313... 

In the reactions of 9 with aromatic azides, the primarily occurring [2 + 3] cycloaddition to afford the disilatriazolines 64 has been confirmed on heating, nitrogen is eliminated from 64 to afford the azadisilacyclopropanes 65 (equation ll)85. 

Some other aromatics azidated in this way included 1,2,3-trimethoxybenzene (at C-5), naphthalene (at C-l), mesitylene, etc. Mechanistic studies have shown that azide reacts as a nucleophile with aryl cation radicals formed through electron abstraction by BTI. With p-alkylanisoles bearing at least one benzylic proton, BTI and Me3SiN3 in acetonitrile gave sp3-C-substitution products, homolytically. Among the R groups were not only alkyls but also cyano, nitro and others [102]. 

Didehydroazepines as intermediates in the photolysis of aromatic azides 92UK910. 

Warrier, M., M.K.F. Lo, H. Monbouquette and M.A. Garcia-Garibay (2004). Photocatalytic reduction of aromatic azides to amines using CdS and CdSe nanoparticles. Photochemical and Photobiological Sciences, 3(9), 859-863. 

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