Azides special

Decompn of alpha LA] 5) H.W. Voight Jr F.H. Schmitt, PATM 1673 (1965) (Low-impulse LA film to be used in applications calling for light-initiated plane wave explosives) 6) Spec, Lead Azide (Special Purpose, For Use in Ammunition) , MIL-L-14758 (10 May i968) 7) Anon, Lead Azide RD-1333 ,... 

Only relatively few compounds can act as primary explosives and still meet the restrictive military and industrial requirements for reflabiUty, ease of manufacture, low cost, compatibiUty, and long-term storage stabiUty under adverse environmental conditions. Most initiator explosives are dense, metaHoorganic compounds. In the United States, the most commonly used explosives for detonators include lead azide, PETN, and HMX. 2,4,6-Triamino-l,3,5-triuitrobenzene (TATB) is also used in electric detonators specially designed for use where stabiUty at elevated temperatures is essential. 

Special reactions of hydrazides and azides are illustrated by the conversion of the hydrazide (205) into the azide (206) by nitrous acid (60JOC1950) and thence into the urethane (207) by ethanol (64FES(19)105Q) the conversion of the same azide (206) into the N-alkylamide (208) by ethylamine the formation of the hydrazone (209) from acetaldehyde and the hydrazide (205) and the IV-acylation of the hydrazide (205) to give, for example, the formylhydrazide (210) (65FES(20)259). It is evident that there is an isocyanate intermediate between (206) and (207) such compounds have been isolated sometimes, e.g. (211). Several of the above reactions are involved in some Curtius degradations. 

Few of the many other inorganic compounds of Ge, Sn and Pb call for special comment. Many pseudo-halogen derivatives of Sn, Pb and Pb have been reported, e.g. cyanides, azides, isocyanates, isothiocyanates, isoselenocyanates and alkoxides. ... 

The disulfide has a special interest as the catalyst in the carbon disulfide-catalyzed iodine-azide reaction. No perceptible nitrogen evolution will take place in a solution containing iodine and azide ions without the presence of a catalyst. Thiosulfates, sulfides, and many other sulfur compounds act as catalysts. In 1922 Browne et found that carbon disulfide is a powerful catalyst in this... 

The ring-opening reactions of aziridines 16 with amines deserve special attention. Unlike ring-openings with the other nucleophiles examined, they do not require added base, and they do not produce stoichiometric byproducts (as with azide). In certain cases, they do not even require a solvent, as exemplified by the ring-opening of aziridine 18 (Table 12.12, entries 1-3). In addition, the reactions... 

The reaction of Lead Azide (LA) with Cu (see Table) deserves special comment, Although this reaction is relatively slow, even in the presence of w, some forms of Cu Azide are so sensitive that they create a serious hazard even in minute quantities, particularly when in contact with LA. For this reason, AJ and stainless steel containers are now used exclusively. PicArsn requires that all new fuze designs contain no Cu or Cu alloys, with the possible exception of the electrical system. Even here, the Cu must be coated for protection against the formation of hydrazoic acid. Another prohibition involves the use of Pb thiocyante in contact with A1 (Refs 4, 5 6)... 

Aziridines can be prepared directly from double-bond compounds by photolysis or thermolysis of a mixture of the substrate and an azide. The reaction has been carried out with R = aryl, cyano, EtOOC, and RSO2, as well as other groups. The reaction can take place by at least two pathways. In one, the azide is converted to a nitrene, which adds to the double bond in a manner analogous to that of carbene addition (15-62). Reaction of NsONHC02Et/ CuO [Ns = A(/7-toluenesulfonyl-inimo)] and a conjugated ketone, for example, leads to the A-carboethoxy aziridine derivative.Calcium oxide has also been used to generate the nitrene.Other specialized reagents have also been used." ... 

Nitrilium salts, e.g., 66, prepared from the alkylation of nitriles, react with sodium azide to yield 1,5-disubstituted tetrazoles, e.g., 67 (Scheme 7).121 The Schmidt reaction,122 a versatile method for the preparation of 1,5-disubstituted tetrazoles from ketones and hydrazoic acid, can now be regarded as a special case of azide addition to nitrilium salts.123... 

Scheme 22 illustrates a special application of the azide-tetrazole ring closure described by Ponticelli et al. <2004JHC761>. The diazido compound 84 exists as an azide valence bond isomer. When this compound, however, is subjected to reduction by molybdenum hexacarbonyl, one azido group undergoes reduction selectively to an... 

A special, isotope-labeled case of the azide-tetrazole equilibrium was studied by Cmoch et al. <2000JP0480>, and the results are shown in Scheme 23. 2-Chloro-3-nitropyridine 86 was treated with potassium azide containing a doubly labeled (15NN15N) azide anion. The authors detected formation of two differently labeled tetrazolopyridines the 2,4- 87 and the 1,3-labeled 88 derivatives. 

Sato et al. carried out detailed studies on the possibilities of transformation of tetrazolo[l,5-tf]pyrazines 54 to 2-aminopyrazines 56 < 1994S931 >. These authors found that the generally used methods for this conversion fail because the starting compound exists in the stable bicyclic form 54, whereas partial formation of the azide valence bond isomer 55 would be necessary for the success of the transformation. Application of special reaction conditions succeeded, however hydrogenation over palladium catalyst in the presence of ammonium hydroxide or treatment with stannous chloride in a mixture of methanol and hydrochloric acid solved this problem. Thus, a great number of derivatives of 54 was reduced to the corresponding 2-aminopyrazine 56 in medium to high yields (45-100%). 

Detonators are used to detonate high explosives. Stab detonators are initiated by sharp firing pins and are used in explosive trains of different types of fuses. Flash detonators are initiated by flames produced by safety fuses, primers, or delay elements. A special type of flash detonator ignited by the flame of a safety fuse is called a blasting cap. Detonators are primarily composed of three types of explosives including sinoxid mixtures, lead azide-based mixtures, and mercury fulminate-based mixtures. 

The pseudohalogen concept can be extended (i) to some special nonplanar anions such as CF3, (ii) to heavier elements (isovalence electronic exchange of O by S, Se, Te of N by P etc. in SCN , SeCN , TeCN , P(CN)2 ) " and (iii) to derivatives such as the five-membered ring anion [CS2N3] which can be obtained in the reaction of carbon disulfide and sodium azide as shown by Sommer as early as 1915. The introduction of heavier elements, however, results in weaker delocalization effects due to the formation of weaker tt-bonds. 

Special cases of this reaction are the syntheses of TP betaines (53, see below) from pyrimidin-2-ylcarbamoyl chlorides and trimethylsilyl azide [89JCS(P1)1727] and of TP-1-oxides (31, see below) form pyrimidin-2-yl sulfimides and nitrile oxides [76JCS(P1)2166]. 

Since many azides may be explosive compounds, investigators planning to work with them should consult the literature and take special precautions. See Volume I, Chapter 15, Diazo and Diazonium Compounds, for additional information about diazo hydrocarbons. 

Subsequently, the lead azide is transferred into composition boxes behind a protective wall. Sifting takes place in a separate bulding, on a special vibratory sieve. The explosive is poured out of the composition boxes into the sieve funnel in a safe place behind a protective wall. The sifted lead azide is collected in an empty composition box placed underneath. 

To determine the sensitiveness to detonation of mining explosive in some countries (including Poland) special standard detonators have recently been introduced, containing 0.05, 0.1,0.t5, 0.20 g etc. of silver azide. The stronger contains 0.60 g of silver azide or an equivalent quantity of lead azide. 

K.J.Holloway, ERDE (Explosives Research Development Establishment) Rept No 17/R/ 53(1953) (Manuf of RD-1333 LA) (Conf) 13) M.Falcione, GLR 54-HI-1354, PicArsn (1954) "Hygroscopicity of Dextrinated Lead Azide 14)D.E.Seeger, PATR 2198(1955), "Development of the M47 (T32E1) Detonator 15) Armour Research Foundation, Contract No DAI-ll-022-ORD-(P)-18, Rept No 6, 25 Apr 1956(CrystalIographic props of primary expls) l6)B. Furini, Jr, EPR (Eastern Process Rept)-220, No 10, Serial No 30, E.I. du Pont de Nemours Co (1956), "Special RD-1333 Lead... 

Disctission. In the opinion of Croom Prist era (Ref 15, pp 4-5), although the Brit ERDE method is applicable to all LA s and is the simplest (because it does not require any special equipment),it is undesirable because it is very tedious and because Ag azide pptd in the course of analysis is a very sensitive -.1 wni roin t. p.f k... 

The most reliable method for generating nitrenes is the thermal or photochemical elimination of nitrogen from azides. An alternative method which is useful for indole and carbazole synthesis is the deoxygenation of aromatic nitro compounds with trivalent phosphorus compounds. Triethyl phosphite is the most commonly used reagent, though more reactive compounds may be useful in special cases (B-79MI30600). 

It has been known for many years, however, that the (3-branched amino acids, especially valine and isoleucine, cause problems in synthesis,14,5] and special care and additional reaction time are required when -substituted amino acids are added to a growing peptide chain in synthesis. For example, in the synthesis of [2,4-diisoleucine]oxytocin efforts to couple the isoleucine to isoleucine by the azide method failed and only the rearranged product was obtained 61 Also, it is much more difficult to hydrolyze peptide bonds formed between two or more contiguous -substituted amino adds using standard 6M HC1 conditions. For example, in the hydrolysis of [2,4-diisoleucine]oxytocin (3 isoleucine residues adjacent to each other) complete hydrolysis takes 60 hours. 

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