From alkyl azides

The molar rtfraction [R] and magnetic rotation [M] were measured with the sodium D line the value of [R] for the azido group was derived from alkyl azides. In phenyl derivatives it increases to about 10-2 . This results from conjugation of N3 with the aromatic ring optical exaltation effect) [M] is related to the Faraday effect (sec reference 16 for a simple discussion, and reference 18a for a recent review. 

Photolysis of the aryl-alkyl azide CH CPhaNa showed that the migratory aptitudes of the methyl and phenyl groups were almost identical and this and the formation of triphenylmethyl amine from irradiation of triphenylmethyl azide in the presence of efficient hydrogen donors were taken to confirm the existence of discrete nitrene intermediates. Although the occurrence of a triplet-sensitized decomposition from alkyl azides and triphenylmethyl azides (the... 

N-Boc amines. Iminophosphoranes derived from alkyl azides are converted to the protected amines by t-BuOCOO-N=C(Ph)CN. 

Alkyl-5-arylsulfonylimino-4,5-dihydro-1,2,3,4-thiatriazoles (53) are readily accessible from alkyl azides and sulfonyl isothiocyanates.69 Their thermo-... 

Thiocarboxylic acids react with phosphazenes (R -N=PPh3, Staudinger intermediate) generated from alkyl azides and electron-deficient triarylphos-... 

Scheme 39 Three component synthesis of 5-imino-l,2,4-thiadiazolidine-3-ones 199 from alkyl azides 195, allqd or ar)4 isocyanates 196 and ar)4 isothiocyanates 197 [ 142]...

Cu2(OTf)2 PhH complex was used to catalyze tetrazole formation from alkyl azides and electron deficient nitriles. In this instance, the sterics seem to modulate the amount of 1,5- and 2,5-disubstituted tetrazoles. Increased Cu loading provided more 2,5-disubstituted tetrazole. Bosch et al. reported either stirring at room temperature or using microwave irradiation to promote the reaction. Mild conditions and modest to excellent yields of the 1,5-disubstituted tetrazole 41 were reported using 10 mol% catalyst. However, when more than 50 mol% of Cu2(OTf)2 PhH complex was used, the 2,5-disubstituted tetrazole predominated. The rationale for the difference in selectivity was suggested to be due to Cu forming a complex, with both the nitrile and the azide and altering the mode of addition. 

Similar cycloadducts are obtained from alkyl azides and chlorosulfonyl isocyanates and from alkyl- or aryl azides and arenesulfonyl isocyanates. Similarly, trimethylsilyl azide reacts with aryl isocyanates to give the [3-1-2] cycloadducts... 

Alkvl Azides from Alkyl Bromides and Sodium Azide General procedure for the synthesis of alkyl azides. In a typical experiment, benzyl bromide (360 mg, 2.1 mmol) in petroleum ether (3 mL) and sodium azide (180 mg, 2.76 mmol) in water (3 mL) are admixed in a round-bottomed flask. To this stirred solution, pillared clay (100 mg) is added and the reaction mixture is refluxed with constant stirring at 90-100 C until all the starting material is consumed, as obsen/ed by thin layer chromatographv using pure hexane as solvent. The reaction is quenched with water and the product extracted into ether. The ether extracts are washed with water and the organic layer dried over sodium sulfate. The removal of solvent under reduced pressure affords the pure alkyl azides as confirmed by the spectral analysis. ... 

CAUTION All azides, particularly low molecular weight acyl and alkyl azides, are explosive, and great care should be taken while preparing and handling these materials. In addition, hydrazoic acid, which is liberated from unbuffered aqueous solutions of sodium azide, is highly toxic and all operations involving its use should be carried out in an efficient fume hood. 

The synthesis and mechanism of formation of a triazene from an arenediazonium ion and an amine with one or two aliphatic substituents (see Scheme 13-1, R = alkyl, R = H or alkyl) will be discussed in Section 13.2. Here we will briefly mention Dimroth s method (1903, 1905 a) for synthesis of wholly aliphatic triazenes (Scheme 13-6, R and R = alkyl). Dimroth obtained these by the action of Grignard reagents on alkyl azides followed by isolation via copper(i) salts. The Grignard method can also be applied for the synthesis of triazenes with an aromatic substituent by using an aryl azide. 

Tertiary alkyl azides can be prepared by stirring tertiary alkyl chlorides with NaN3 and ZnCl2 in 82 ° or by treating tertiary alcohols with NaN3 and CF3-COOH or with HN3 andTiCl4 or BF3. Acyl azides, which can be used in the Curtius reaction (18-14), can be similarly prepared from acyl halides, anhydrides, " esters, or other acyl derivatives. ° Acyl azides can also be prepared... 

There are also useful procedures for preparation of azides directly from alcohols. Reaction of alcohols with 2-fluoro-l-methylpyridinium iodide followed by reaction with lithium azide gives good yields of alkyl azides.75... 

Quaternary ammonium azides will displace halogens in a synthesis of alkyl azides. Dichloromethane has been used as a solvent, although this can slowly form diazido-methane which may be concentrated by distillation dining work-up, thereafter easily exploding [1]. An accident attributed to this cause is described, and acetonitrile recommended as a preferable solvent, supported polymeric azides, excess of which can be removed by filtration are also preferred in place of the tetrabutylam-monium salt [2]. A similar explosion was previously recorded when the quaternary azide was generated in situ from sodium azide and a phase transfer catalyst in a part aqueous system [3,4],... 

The use of reductive alkylation conditions has been employed to access tricycles from the azide 353 <2002S242> (Equation 95). Hydroboration of the alkene double bond with dicyclohexylborane followed by reaction with the azide and subsequent elimination of nitrogen and cyclization gave the linear tricyclic diketopiperazine 354 and 355 as a mixture of diastereoisomers. 

The direct formation of A-substituted phthalimides from phthalic anhydride and alkyl azides, via the intermediate RN=PPh, compound, is catalysed by the presence of tetra-n-butylammonium cyanide [34],... 

Relatively few additions of the lower molecular weight alkyl azides have been performed, mainly because of their volatility and thermal sensitivity simple alkyltriazoles are normally obtained by alkylation of the w-triazoles. On the other hand, a very wide range of less volatile substituted alkyl azides has been added to acetylenes Their addition to acetylenic esters usually proceeds readily and provides a useful method of characterizing the azides. Benzyl azide has often been used because it is relatively stable (up to 150°), it is readily prepared, and the benzyl group can be removed from the resulting triazoles (Section IV, E). 

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