Azides, alkyl

Alkyl azides are conveniently prepared from the reaction of alkali metal azides with an alkyl halide, tosylate, mesylate, nitrate ester or any other alkyl derivative containing a good leaving group. Reactions usually work well for primary and secondary alkyl substrates and are best conducted in polar aprotic solvents like DMF and DMSO. The synthesis and chemistry of azido compounds is the subject of a functional group series.  

Frankel and co-workers prepared a series of alkyl diazides from the reaction of dihaloalka-nes with sodium azide in DMF at 95 °C, including 1,3-diazidopropane, 1,4-diazidobutane and l,3-diazido-2,2-dimethylpropane. Tris(azidomethyl)amine, an energetic fuel with potential for use in bipropellant propulsion systems, is synthesized from the reaction of tris(chloroethyl)amine with sodium azide.  

Organic Chemistry of Explosives J. P. Agrawal and R. D. Hodgson 2007 John Wiley Sons, Ltd. 

Agrawal and co-workers synthesized the energetic plasticizer bis(2-azidoethyl)adipate (2) (BAEA) from the reaction of bis(2-chloroethyl)adipate (1) with sodium azide in ethanol (72 %). 

Drees and co-workers synthesized a number of energetic azido plasticizers whose structures are based on those of known nitrate ester plasticizers. EGBAA (3), DEGBAA (4), TMNTA (5) and PETKAA (6) are synthesized from the corresponding chloroacetate esters with sodium azide in DMSO. 

The photolysis of cyanogen azide has been examined in both the vapour and solid phases. In the solid phase, ESR measurements showed the presence of NCN using filtered radiation (2800-3000 A) and triplet CNN using unfiltered light. In the vapor phase flash photolysis, the following steps have been established by kinetic spectroscopy  

NCN was also identified as a transient species in the solid phase by the matrix isolation technique developed by Milligan and Jacox . Photolysis at shorter wavelengths affords NNC via 

Methyl azide in the gas phase undergoes a homogeneous unimolecular decomposition in which the rate determining step is the characteristic nitrogen elimina- 

The vapor phase photolysis above 2500 A yields mainly Nj, a condensate of empirical formula CH3N, and traces of CH4, C2H4 and C2Hg . The quantum yield of N2 formation is 2. It was concluded that the major primary process is 

Photolysis in the vacuum ultraviolet (1800-2400 A) resulted in the formation of nitrogen, ammonia and hexamethylenetetramine, in yields similar to the thermal decomposition. Hexamethyenetetramine was also a major product in photol-yses above 2400 A and it seems probable that both the thermal and photochemical decompositions proceed by the same mechanism. The solution photolysis of methyl azide has recently been examined and the general kinetic features are similar to the vapor-phase photolysis and thermolysis. Thus increases with CH3N3 concentration to a maximum of 2, and hexamethylenetetramine and N2 were the major products. It is believed that in solution CH3N does not isomerize but condenses with CH3N3 in several steps to produce hexamethylenetetramine. 

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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. ... 

Sulfonium ylides may be added to C N double bonds to yield aziridines in a formal [1 -t-2]-cycloaddition. Alkyl azides are decomposed upon heating or irradiating to yield ni-trenes, which may also undergo [ 1 + 2 -cycloaddition reactions to yield highly strained hetero-cycles (A.G. Hortmann, 1972). 

The alkyl azide 118 is reduced to a primary amine by the Pd on carbon-catalyzed reaction of ammonium formate in MeOH at room temperature. No racemization takes place with chiral azides[l 11,112]. 

Azide ion ( N=N=N ) Sodium azide IS a reagent used for carbon-nitrogen bond formation The product IS an alkyl azide... 

Azide ion Alkyl halide Alkyl azide Halide ion... 

Nucleophilic substitution by azide ion on an alkyl halide (Sections 8 1 8 13) Azide ion IS a very good nucleophile and reacts with primary and secondary alkyl halides to give alkyl azides Phase transfer cata lysts accelerate the rate of reaction... 

Alkyl azides prepared by nucleophilic substitution of alkyl halides by sodium azide as shown m the first entry of Table 22 3 are reduced to alkylammes by a variety of reagents including lithium aluminum hydride... 

Alkyl azides prepared by nucleophilic substitution by azide ion in primary or secondary alkyl halides are reduced to primary alkylamines by lithium aluminum hydride or by catalytic hydrogenation... 

The procedure described is essentially that of Shioiri and Yamada. Diphenyl phosphorazidate is a useful and versatile reagent in organic synthesis. It has been used for racemlzatlon-free peptide syntheses, thiol ester synthesis, a modified Curtius reaction, an esterification of a-substituted carboxylic acld, formation of diketoplperazines, alkyl azide synthesis, phosphorylation of alcohols and amines,and polymerization of amino acids and peptides. - Furthermore, diphenyl phosphorazidate acts as a nitrene source and as a 1,3-dipole.An example in the ring contraction of cyclic ketones to form cycloalkanecarboxylic acids is presented in the next procedure, this volume. 

In recent years the applicability of the Schmidt reaction for the synthesis of more complex molecules—especially the variant employing alkyl azides—has been further investigated. Cycloketones bearing an azidoalkyl side-chain at the a-carbon center have been shown to undergo, upon treatment with trifluoroacetic... 

Intermolecular Schmidt reactions of alkyl azides and hydroxyalkyl azides with cycloketones in the presence of a Lewis acid, lead to formation of iV-alkyl lactams and A-hydroxyalkyl lactams respectively in good yield. The synthesis of chiral lactams by an asymmetric Schmidt reaction has also been reported. ... 

A better method for preparing primary amines is to use the azide synthesis, in which azjde ion, N3, is used for SN2 reaction with a primary or secondary alkyl halide to give an alkyl azide, RN3. Because alkyl azides are not nucleophilic, overalkylation can t occur. Subsequent reduction of the alkyl azide, either by catalytic hydrogenation over a palladium catalyst or by reaction with LiAlK4. then leads to the desired primary amine. Although the method works well, low-molecular-weight alkyl azides are explosive and must be handled carefully. 

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. 

A novel approach to azabicyclic ring systems, based on an epoxide-initiated electrophilic cyclization of an alkyl azide, has been developed by Baskaran. A new stereo- and enantioselective synthesis of the 5-hydroxymethyl azabicyclic framework 91a, present in (+)- and (-)-indolizidines 167B and 209D, for example, was... 

Molar Refraction. The molar refraction of the azido group in alkyl azides was estd to be ca 9,4 (Ref 14). For a discussion of molar refraction see Ref 9, p 528... 

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. 

Alkyl azides can be prepared by treatment of the appropriate halide with azide ion. ° Phase-transfer catalysis,ultrasound,and using reactive clays as a... 

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... 

A C N 1,2-aryl rearrangement was observed when alkyl azides were treated with n-Bu3SnH, proceeding via an C—N —SnBu3 species to give an imine. ... 

Alkyl azides can be similarly pyrolyzed to give imines, in an analogous... 

With alkyl aryl ketones, it is the aryl group that generally migrates to the nitrogen, except when the alkyl group is bulky. The reaction has been applied to a few aldehydes, but rarely. With aldehydes the product is usually the nitrile (16-21). Even with ketones, conversion to the nitrile is often a side reaction, especially with the type of ketone that gives 17-31. A useful variation of the Schmidt reaction treats a cyclic ketone with an alkyl azide (RN3) in the presence of TiCU, generating a... 

Alcohols and alkenes react with HN3 to give alkyl azides, which in the course... 

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