Hydrogen azide reactions

Isothiocyanates react with hydrogen azide to give 5-alkyl- (or -aryl-)-aminothiatriazoles [Eq. (3)]. This reaction is of... 

A different reaction takes place between an ethereal solution of the disulfide and hydrogen azide this reaction proceeds according to Eq. (15). Probably the principal step of this reaction is the spontaneous decomposition of the disulfide into nitrogen, sulfur, and... 

Puacz et al. (1995) developed a catalytic method, based on the iodine-azide reaction, for the determination of hydrogen sulfide in human whole blood. The method involves the generation of hydrogen sulfide in an evolution-absorption apparatus. In addition, the method allows for the determination of sulfide in blood without interference from other sulfur compounds in blood. A detection limit of 4 g/dm3 and a percent recovery of 98-102% were achieved. Although the accuracy and precision of the catalytic method are comparable to those of the ion-selective electrode method, the catalytic method is simpler, faster, and would be advantageous in serial analysis. 

A violent explosion occurred during vacuum distillation of 4-chlorophenyl isocyanate, prepared by Curtius reaction from the azide. It was found by IR spectroscopy that this isocyanate (as well as others prepared analogously) contained some unchanged azide, to which the explosion was attributed. The use of IR spectroscopy to check for absence of azides in isocyanates is recommended before distillation [1], Subsequently, the explosion was attributed to free hydrogen azide, produced by hydrolysis of the unchanged acyl azide [2],... 

An explosion was experienced dining work up of an epoxide opening reaction involving acidified sodium azide in a dichloromethane/dimethyl sulfoxide solvent. The author ascribes this to diazidomethane formation from dichloromethane [1]. A second report of an analoguous accident, also attributed to diazidomethane, almost certainly involved hydrogen azide for the cold traps of a vacuum pump on a rotary evaporator were involved this implies an explosive more volatile than dichloromethane. It is recommended that halogenated solvents be not used for azide reactions [2]. 

Ray, P. C. et al., J. Chem. Soc., 1911, 99, 1470 1912, 101, 141, 216 Ammonium and substituted-ammonium nitrite salts exhibit a range of instability, and reaction mixtures which may be expected to yield these products should be handled with care. Ammonium nitrite will decompose explosively either as the solid, or in cone, aqueous solution when heated to 60-70°C. Presence of traces of acid lowers the decomposition temperature markedly. Hydroxylammo-nium nitrite appears to be so unstable that it decomposes immediately in solution. Hydrazinium(l+) nitrite is a solid which explodes violently on percussion, or less vigorously if heated rapidly, and hydrogen azide may be a product of decomposition [1], Mono- and di-alkylammonium nitrites decompose at temperatures below 60-70°C, but usually without violence [2], Individual entries are ... 

They et al. (1993) evaluated the degradation of aldicarb at nine different temperatures. When aldicarb was oxidized at a temperature range of 275-650 °C, the following reaction products were identified by GC/MS acetone, 2-methyl-2-propenenitrile, methylthiopropene, dimethyl disulfide, carbon dioxide, carbon monoxide, nitrous oxide, isocyanatomethane, hydrogen azide, sulfur dioxide, hydrogen cyanide, and 2-propenenitrile. 

The azides of the 1,1 -diphenyl series were prepared by adding hydrogen azide to the appropriate olefin. The reaction is catalyzed by trichloroacetic acid and carried out in benzene solution [56],... 

The reaction is monomolecular. The half-life at 330°C is 12 min. In a dilute aqueous solution hydrazoic acid is stable and not liable to decompose even on long boiling (Curtius [46]). However, a 17% aqueous solution of hydrogen azide can probably detonate [47]. 

The majority of pyrimido[4,5-c]pyridazines have been prepared from pyrimidine precursors. The chloropyrimidines (176) give the desired heterocyclic ring (177) on reaction with hydrazine (72BSF1483). Hydrazine also reacts with ethyl a-diazo-/3-oxo-5-(4-chloro-2-methylthiopyrimidine)propionate (178) to give the pyrimido[4,5-c]pyridazine-3-carboxamide (78). A mechanism for this interesting reaction has been proposed as shown, on the basis of the detection of hydrogen azide in the reaction mixture. There is no precedent for the reaction of the a-carbon of a-diazo-/3-oxopropionates with nucleophiles under basic conditions (76CPB2637). 

Some new 5-(benzylamino)thiatriazoles have been prepared by standard methods.12 5-(Tetra-0-acetyl-/T-D-glucopyranosylamino)-thia-triazole was prepared by the action of HN02 on 4-(tetra-0-acetyl-/3-D-glucopyranosyl)thiosemicarbazide as well as from hydrogen azide and tetra-0-acetyl-/J-D glucopyranosyl isothiocyanate.62 Substituted 5-aminothiatriazoles may be obtained from C-sulfonylthioformamides on reaction with azide ion.63... 

The acid-catalysed reaction of hydrogen azide with electrophiles, such as carbonyl compounds, tertiary alcohols or alkenes. After a rearrangement and extrusion of N2, amines, nitriles, amides or imines are produced. 

The different reactivity of phosphorus azides might be interpreted in terms of conjugation between phenyl groups and sulfur or between phenyl groups and the P=N=0 double bond in these cases the rate of the phenyl migration decreases and hydrogen abstraction reactions dominate. 

Nitrilium ions are generally indicated as discrete intermediates in the Beckmann rearrangement of oximes (equation 37, Y = OH2) and in the Schmidt rearrangement (equation 37, Y = N2) of ketones and aldehydes with hydrogen azide. The first stage of these reactions has been defined as an ionization by rearrangement process through a transition state of type 183 (Smith, 1963). 

Nitrites give a similar reaction and may be removed most simply with the aid of sulphamic acid (see reaction 3). Another, but more expensive, procedure involves the addition of sodium azide to the acid solution the solution is allowed to stand for a short time and then boiled in order to complete the reaction and to expel the readily volatile hydrogen azide ... 

Caution Parts A and C of this procedure should be carried out in a well-ventilated hood since toxic hydrogen bromide and azidotrimethylsilane are handled and toxic hydrogen azide is liberated during the course of the reaction. 

The reaction of azidotrimethylsilane and ethanol, which gives hydrogen azide and ethoxytrimethylsilane, is exothermic and the hydrogen azide immediately forms a salt with 4-(dimethylamino)pyridine, a part of which cannot be dissolved in N,N-dimethylformamide and precipitates. 

An alternative route to the Step 1 product was by hydrogenating the reaction product of N-t-butoxycarbonyl-4-piperidylethyl methane-sulfonate with sodium azide and is described by the author. 

SAFETY PROFILE Confirmed human carcinogen. Hydrolysis reaction in the presence of moisture forms the explosive hydrogen azide gas. When heated to decomposition it emits toxic fumes of Cd and NOx. See also CADMIUM COMPOUNDS and AZIDES. 

The reaction of equimolar quantities of hydrazoic acid with an acid or ketone affords a convenient method for preparing certain amines. The reaction is carried out by treating the organic compound in an inert solvent in the presence of sulfuric acid with gaseous hydrogen azide, hydrazoic acid in solution, or sodium azide directly. An excess of hydrazoic acid should be avoided in the reaction of ketones, for then tetrazoles are formed. It should be recalled that hydrazoic acid is toxic and explosive. A discussion of the method including scope and limitations, experimental conditions and procedures, and compounds prepared thereby has been presented. ... 

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