NaN3

The azides are salts which resemble the chlorides in solubility behaviour, for example silver azide, AgNj, is insoluble and sodium azide, NaN3, soluble in water. Sodium azide is prepared by passing dinitrogen oxide over molten sodamide ... 

Ethyl 3-amlnopropsnoate (5). To a tu solution of 4 in THF (frem the bromo ester with NaN3 In OMSO) was added a molar equivalent of Ph3P, t 5 equiv of water and a boiling chip (N2 evolution) Alter 8 h at 20°C and evaporation, the residue was treated with El20-hexane and PhaPO was filtered This process was repeated and 5 was distilled at 40-45° and 10.5 torr (83%). 

If it is assumed that ionization would result in complete randomization of the 0 label in the caihoxylate ion, is a measure of the rate of ionization with ion-pair return, and is a measure of the extent of racemization associated with ionization. The fact that the rate of isotope exchange exceeds that of racemization indicates that ion-pair collapse occurs with predominant retention of configuration. When a nucleophile is added to the system (0.14 Af NaN3), k y, is found to be imchanged, but no racemization of reactant is observed. Instead, the intermediate that would return with racemization is captured by azide ion and converted to substitution product with inversion of configuration. This must mean that the intimate ion pair returns to reactant more rapidly than it is captured by azide ion, whereas the solvent-separated ion pair is captured by azide ion faster than it returns to racemic reactant. 

Reactions of substituted cumyl benzoates in 50 50 trifluoroethanol-water show no effect of [NaN3] on the rate between 0 and 0.5 M. The product ratio, however, is highly dependent on the cumyl substituent. Electron-releasing substituents favor azide formation whereas electron-withdrawing substituents result in solvent capture. Formu-... 

Preswelled Sephacryl S-1000 was prepared in a K26/100 column (88 X 2.6 cm). Equilibration with 0.005 M NaOH containing 0.002% NaN3 at a flow rate of 0.67 ml/min was achieved after 20 hr. Sample solutions were applied with a 5-ml injection loop. The mass and iodine-complexing potential of separated glucan components was determined off-line for each of the subsequently eluted 5-ml fractions. Based on the determined mass of carbohydrate for each of the fractions, elution profiles such as Fig. 16.1 were constructed. 

Degassed and preswelled Bio-Gel P-6 and Sephacryl S-200 were packed in self-made glass columns (70 X 1.5 cm 140 X 1.5 cm) and equilibrated for 20 hr with H20(dest.) -t- 0.002% NaN3 to prevent microbial growth. The mass of eluted fractions was detected with a differential refractive index detector (Waters 403 RI, sensitivity 8). 

In this last reaction Na can be replaced by the azide NaN3 to give the same products. The normal oxides of the other alkali metals can be prepared similarly. 

Numerous metal azides have been characterized (p. 417) and covalent derivatives of non-metals are also readily preparable by simple metathesis using either NaN3 or aqueous solutions of... 

Most preparative routes to HN3 and its derivatives involve the use of NaN3 since this is reasonably stable and commercially available. NaN3 can be made by adding powdered NaN03 to fused NaNH2 at 175° or by passing N2O into the same molten amide at 190° ... 

A remarkable new covalent azide is the pale yellow nitrosyl NNNNO, prepared by reacting gaseous NOCl (p. 441) with solid NaN3 at low temperature.NNNN(S02p)2 has also very recently been made by a similar route from (S02F)2NC1 it is a volatile yellow liquid which sometimes decomposes explosively. 

The major use of inorganic azides exploits the explosive nature of heavy metal azides. Pb(N3)2 in particular is extensively used in detonators because of its reliability, especially in damp conditions it is prepared by metathesis between Pb(N03)2 and NaN3 in aqueous solution. 

Reaction of 4-imino-4/f-pyrido[l, 2-n]pyrimidine-3-carbonitriles 124 with NaN3 in the presence of NH4CI gave 3-(2-pyridylamino)-2-(I//-tetrazol-5-yl)acrylonitriles 125 (93MIP3). 

Reaction of 199 with NaN3 or NH4N3 in DMF at 90-95 °C afforded a 1 4-5 mixture of 200 and ring opened 201 products. When the reactions... 

Reaction of 8-substituted 3-[2-(4-methoxybenzyl)-2//-tetrazol-5-yl]-4//-pyrido[l,2-u]pyrimidin-4-ones with CF3COOH for 2 days at room temperature gave 3-(2//-tetrazol-5-yl) derivatives (OlMIPl). The cyano group of a 3-(8-substituted 2-hydroxy-4-oxo-4//-pyrido[l,2-u]pyrimidin-3-yl)-2-propenenitrile was converted into a 5-tetrazolyl group by treatment with NaN3 in the presence of AICI3 in DMF at 100 °C for 2 days. 

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