Synthesis azide

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. 

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. 

Azide synthesis (Section 24.6) A method for preparing amines by S 2 reaction of an alkyl halide with azide ion, followed by reduction. 

Atorvastatin, structure of, 105. 516 ATP (see Adenosine triphosphate) ATZ, see Anilinothiazolinone, 1031-1032 Aufbau principle. 6 Axial bonds (cyclohexane), 119 drawing, 120 Azide, amines from, 929 reduction of, 929 Azide synthesis, 929 Azo compound, 944 synthesis of, 944-945 uses of. 945... 

It is worth noting that as early as 1903 Hantzsch felt that the possibility of forming the pentazole ring lay in the phenyl azide synthesis. 

A similar result had previously been observed using the azide synthesis, and the unusual stability of these triphosphazenes has now been rationalized in terms of conversion of (27) into the relatively stable cyclic product (28). Evidence for the structure (28) was deduced from its n.m.r. spectrum... 

Aza-Payne rearrangements, 60, 1 Azaphenanthrenes, synthesis by photocyclization, 30, 1 Azides, synthesis and rearrangement of, 3, 9... 

A novel azide synthesis using p-toluenesulfonyl azide and amine anions... 

P. A. M. van der Klein, W. Filemon, G. H. Veeneman, G. A. van der Marel, and J. H. van Boom, Highly regioselective ring opening of five-membered cyclic sulfates with lithium aluminium azide synthesis of azido sugars, J. Carhohydr. Chem., 11 (1992) 837-848. 

Scheme 33 Copper(I)/diamine-catalyzed aryl azide synthesis...

Harvey and Ratts have discovered an interesting vinyl azide synthesis from allenic esters.40 Treatment of allenes (83a and b) with... 

The base-catalyzed condensation of a-azido esters and ketones with aromatic aldehydes has recently been developed as a new vinyl azide synthesis.42,43 The yields range from moderate to excellent in some cases. The thermal decomposition of ethyl a-azidocinnamate (87) in xylene gives only 2-ethoxycarbonylindole (88).44 The unstable 2-ethoxycarbonyl-3-phenyl-l-azirine could be detected if the thermolysis was carried out at a lower temperature. This fact indicates that the 1-azirine is probably an intermediate leading to the indole, although the intermediacy of the vinyl nitrene could not be established. This result is similar to that observed by Isomura et al. on the pyrolysis of terminal vinyl azides.27,28... 

The first three steps show that the reaction sequence in Figure 14.45 actually provides a widely applicable approach to such a-aminophosphonic acids. The step leading to the acyl azide F, i.e., the nitrite oxidation of an acyl hydrazide (Formula C in Figure 14.45), is as commonly used for the preparation of an acyl azide synthesis as that shown in Figure 14.44. 

When the cyano (—C=N) group is added and reduced, the resulting amine has an additional carbon atom. In effect, the cyanide substitution-reduction process is like adding —CH2 —NH2. The following synthesis makes 2-phenylethylamine, which we also made by the azide synthesis ... 

The above directions are based upon the methods of Hoogewerff and Van Doip, as modified by Holm and by Hale and Honan. -Alanine has also been prepared by the action of h3q)obromite upon succinimide and hydrolysis of the resulting /3-ureidopropionic acid by the action of ammonia upon /3-iodo-propionic acid by the hydrolysis of methyl carbomethoxy-/8-aminopropionate, obtained by the action of sodiiun methoxide on succinbromimide by the reduction of 3-nitrosopropionic acid by heating ethyl acrylate with alcoholic ammonia from succinyl-glycine ester by the azide synthesis and by the action of liquid ammonia upon methyl acrylate. ... 

Phenyllead(IV) azides, synthesis 15 Tetraphosphorus hexamethylhexaimide, synthesis 16 Diphenyl phosphorochloridite, synthesis 17 Diphenylphosphinic acid, synthesis 18 (2,2-Dimethylhydrazino)diphenylphosphine, synthesis 19 Alkoxy- and aryloxycyclophosphazenes, synthesis 20 Mercapto derivatives of chlorocyclophosphazencs, synthesis 21 Dialkylsulfamoyl chlorides, synthesis 27 N- and J T,A1 -Substituted sulfamides, synthesis 28 Dialkylamides of (trichlorophosphoranylidene)sulfamic acid, synthesis 29... 

Hydrazoic acid and its alkali metal salts are often used in azide synthesis. Pure hydrazoic acid is violently explosive and the reagent is consequently used in dilute solution in which it is quite stable. Solutions of hydrazoic acid in organic solvents may be conveniently prepared and find general application in azide synthesis " . Silver azide, which has occasionally been used for the preparation of organic azides, is impact sensitive and has been superseded by the alkali metal azides which are not considered explosive under most laboratory conditions. 

Kuezynski and Walkowicz have described an azide synthesis in which the trishomocyclopropenyl cation (19) is formed in the rate-limiting step of an 51,1 reaction of the cw-/ -toluenesulphonate (20). In the presence of azide ion the product was a mixture of the cis and tram azides, 21 and 22, and 3-azido-m-2,2-dimethylbicyclo[3,l,0] hexane (23), which were identified after reduction to the amines. The franj-/>-toluenesulphonate (24), however, afforded only the inverted azide (21) (equation 25), which seems surprising in view of the... 

The method has recently been adapted for azide synthesis by Sokolov and Reutov who reacted mercuric nitrate and sodium azide in dimethylformamide with alkenes such as styrene and cyclohexene The azidomercurials were isolated as the mercurichlorides in 10-25% yield. 

The most obvious route to vinyl azide synthesis lies in the addition of hydrazoic acid to an alkyne. Unfortunately, this reaction has been found to be successful with only one group of compounds, the esters of acetylene dicarboxylic acid (equation 1). Acetylene mono-... 

---