Azides caution

A solution of 5 g (14 mmoles) of 5a-cholest-2-ene in 100 ml ethyl acetate and 8 ml of 2.8 M (22 mmoles) cyanogen azide (CAUTION See Chapter 15 and ref. 139b) in ethyl acetate is heated at 50-53° for 24 hr, during which time about 22 mmoles of nitrogen is evolved. Solvent is removed by evaporation and the residue is applied in benzene to a column of 160 g of neutral alumina (activity grade III). Elution with petroleum ether-benzene (1 1) gives 1.6 g of... 

Aliphatic azides (CAUTION A highly explosive azide may be formed when dichloromethane is used as the solvent)... 

Mobile phase THF buffer 5.5 94.5 (Buffer was 60 mM KH2PO4 adjusted to pH 2.6 with orthophosphoric acid triethylamine 97 3 containing 50 pg/mL sodium azide. Caution Sodium azide is carcinogenic and toxic and must not be discharged to the plumbing system )... 

Mobile phase 50 mM pH 6.8 Phosphate buffer containing 300 mM NaCl and 0.05% sodium azide (Caution Sodium azide is carcinogenic, highly toxic, and can form explosive compounds if discharged to the sewer )... 

Hybridization solution Work in a fume-hood. To a glass bottle containing about 400 mL distilled water add 25 mL 20X SSC, 25 mL 20% (w/v) SDS, 5 g dried skimmed milk (e.g., Marvel), 0.1 g sodium azide (Caution contact with water liberates toxic gas), 50 pL diethyl pyrocarbonate (DEPC Caution suspected carcinogen). Add distilled water to 500 mL. Close the cap firmly and mix thoroughly. Incubate overnight at 42°C with the cap slightly open. Do not autoclave. Store at 4°C. This volume will last for about 10 hybridizations (20 blots). 

All the azides are potentially dangerous, and liable to detonate on heating, but those of the alkali and alkaline earth metals can be heated with caution if pure they then evolve pure nitrogen. 

Caution/ Although the organic azide intermediates used in this procedure ham not shown any explosive hazard under the experimental conditions. 

A mixture of the epoxide ca. 5 mmol), sodium azide (6 g, activated by the method of Smith) and 0.25 ml of concentrated sulfuric acid in 70 ml of dimethyl sulfoxide is heated in a flask fitted with a reflux condenser and a drierite tube on a steam bath for 30-40 hr. (Caution carry out reaction in a hood.) The dark reaction mixture is poured into 500 ml of ice water and the product may be filtered, if solid, and washed well with water or extracted with ether and washed with sodium bicarbonate and the water. The crude azido alcohols are usually recrystallized from methanol. 

Caution The reaction should be carried out in a good hood because hydrazoic acid is very toxic. Care should also be taken in handling sodium azide. 

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. 

No, the editor didn t know what this name meant either.) It means salts of the triva-lent anions of Group V, restricted in [1] to arsenides, antimonides and bismuthides and prepared by reaction of sodium pnictides with anhydrous halides of transition and lanthanide metals. This violently exothermic reaction may initiate as low as 25°C. Avoidance of hydrated halides is cautioned since these are likely to react uncontrollably on mixing. Another paper includes a similar reaction of phosphides, initiated by grinding [2], Nitrides are reported made from the thermally initiated reaction of sodium azide with metal halides, a very large sealed ampoule is counselled to contain the nitrogen [3],... 

CAUTION Phenyl azide decomposes violently when heated at 80°C or above. Care must be taken that the bath temperature never exceeds 60°-70°C. The product should be stored in a cool place in brown bottles. 

CAUTION Many organic and inorganic azides are unstable or explosive under appropriate conditions of I initiation. Appropriate safety precautions and procedures should be adopted when handling these substances... 

CAUTION Sodium azide (NaN3) and phenyl acetate are poisonous. Toluene is not recommended since it is carcinogenic. Take appropriate precautions when using any of these chemicals. See appendix 2B for more information. 

---