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Hydrazoic acid, preparation

A solution of hydrazoic acid (prepared from about 30 g sodium azide) in ca. 200 ml chloroform is prepared in a well-ventilated hood. Cholesterol (15 g) is dissolved in the hydrazoic acid solution and 3.5 ml of triethylamine is added. The reaction mixture is then stirred at room temperature while 7 g of A-chlorosuccinimide is added. The reaction mixture is allowed to stand overnight and then the chloroform solution is washed successively with dilute sodium bisulfite, dilute soldium bicarbonate solutions and finally with water. The chloroform extract is then dried (Na2S04) and the solvent removed in vacuo. The residue is crystallized from ethanol to yield ca. 8.5 g of (101) in colorless needles mp 138-139°. The chloro azide is reduced to the aziridine by lithium aluminum hydride according to the foregoing procedure. [Pg.34]

Preparation. A dried ethereal solution of hydrazoic acid (prepared by adding 80 ml. of coned. HC1 to a cold solution of 1 mole of sodium azide in 200 ml. of water over 30 min. and then extracting with ether) was added to a solution of 1 mole of tetramethylguanidine (1) in 750 ml. of ether at 0°. The product (2) was slurried with two portions of ether and crystallized from chloroform-ether. [Pg.478]

Silver Azide. Silver a2ide, AgN, is prepared by treating an aqueous solution of silver nitrate with hydrazine (qv) or hydrazoic acid. It is shock-sensitive and decomposes violendy when heated. [Pg.89]

The Schmidt reaction of ketones works best with aliphatic and alicyclic ketones alkyl aryl ketones and diaryl ketones are considerably less reactive. The reaction is only seldom applied to aldehydes as starting materials. The hydrazoic acid used as reagent is usually prepared in situ by treatment of sodium azide with sulfuric acid. Hydrazoic acid is highly toxic, and can detonate upon contact with hot laboratory equipment. [Pg.253]

Hydrazoic acid reaction with cyclobu-tanecarboxyhc acid, 47, 28 Hydrogenation of t butylazidoacetate to glycme ( butyl ester, 46,47 Hydrogen bromide 46, 43 reaction with y butyrolactone, 46, 43 Hydrogen fluoride anhydrous, precautions in use of, 46, 3 in preparation of mtromum tetra-fluoroborate 47, 57 reaction with benzoyl chloride, 46,4 with boron tnfluonde in conversion of p cymene to m cymene, 47, 40 in bromofluorination of 1 heptene, 46, 11... [Pg.130]

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. [Pg.137]

Preparation. It was first prepd by wanning a strongly alk soln of Na azide with Me sulfate (Refs 2 20), and this is the only practical prepn. It has also been prepd by the reactn of diazomethane with hydrazoic acid (Ref 6)... [Pg.84]

The most general reaction for the preparation of sulphoximines from sulphoxides is simply by reaction with hydrazoic acid (equation 65)178. Highly substituted sulphoxides, such as diethyl sulphoxide with more than two chlorine substituents, do not undergo reaction to form the sulphoximine in this way. [Pg.989]

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... [Pg.223]

Insensitive to impact, it decomposes, sometimes explosively, above its m.p. [1], particularly if heated rapidly [2], Although used in aqueous solutions as a preservative in pharmaceutical preparations, application of freeze-drying techniques to such solutions has led to problems arising from volatilisation of traces of hydrazoic acid from non-neutral solutions, condensation in metal lines, traps or filters, and formation of heavy metal azides in contact with lead, copper or zinc components in the drying plant [3,4],... [Pg.1802]

Hydrazine hydrate, 50, 3 Hydrazoic acid, safe substitute for, 50, 107 HYDRAZONES, PREPARATION, 50,... [Pg.60]

Most of the important general methods of forming IZf-triazole derivatives involve azides several reviews discuss aspects of the formation of triazoles in this way. a-Diketones are also important precursors of both H- and 2 f-triazoles. Triazoles unsubstituted on nitrogen can be prepared by the direct addition of hydrazoic acid or of azide ion, but it is often more convenient to obtain these compounds by removal of a substituent from a H- or 2if-substituted triazole (Section IV, E). [Pg.34]

The synthesis of tetrazolopiperazines 191 was achieved by Bienayme et al. via Ugi reaction of primary amines 192, aldehydes 193, hydrazoic acid 194, and Schollkopf isocyanide 195 [57]. This transformation was used to prepare large arrays of drug-like molecules (Scheme 34). Overall yields for this highly efficient process were fair to good. [Pg.116]

A recent endeavor at the total synthesis of isopavines describes a promising novel route to these bases via functionalized dibenzocyclooctadienes (Scheme 27) 148). Dibenzocyclooctadienyl ether 132, formed from homoveratraldehyde (131) by a double Friedel-Crafts alkylation, is converted to dibenzocyclooc-tatrienol 133. Treatment with hydrazoic acid, followed by thermolysis and reduction, supplies ( )-isopavine (35) in good overall yield (53%). Subsequent attempts to prepare pavine bases by this approach have proved to be unsuccessful 148). [Pg.356]

Aminothiatriazoles (13) may alternatively be prepared from isothiocyanates and hydrazoic acid (Equation (16)) <77CCC1557, 80CCC2329, 81BSB63>. [Pg.726]

Thiatriazole-5-thiol and its salts are readily obtained from the water-soluble alkali or alkaline earth azides with CS2 at 40 °C <64AHC(3)263>. However, these salts should be handled with extreme care as violent explosions have been reported when the alkali salts are spread on a porous plate or rubbed with a spatula. The slightly soluble heavy-metal salts are very sensitive to shock even under water. An improved method for the preparation and storage of sodium thiatriazole-5-thiolate has been reported. The free acid is obtained by addition of concentrated hydrochloric acid to a chilled solution of the sodium salt but can also be prepared from hydrazoic acid and carbon disulfide (Scheme 38). [Pg.727]

Hydrazoic acid is prepared by reacting sulfuric acid with sodium azide H2SO4 + NaNs — HN3 -I- Na2S04 or by treating hydrazine with nitrous acid ... [Pg.341]

Hassner et al. (8) reported a novel synthesis of 2,5-dihydroxyoxazoles (32) using an intramolecular azide-alkene cycloaddition. The ratio of reagents (aldehyde/allyl alcohol/hydrazoic acid, 1 3 9) was critical for the preparation of azide 30 (Scheme 9.8). [Pg.627]

Hydrazine is used for the preparation of hydrazoic acid according to ... [Pg.192]

The seemingly complex imidazolone (78-3) is in fact obtained in a single step by reaction of the amino-ester (78-1) with the iminoether (78-2) derived from capro-nitrile. The relatively acidic proton on the heterocyclic ring is next removed by reaction with sodium hydride. This anion is then alkylated with the same biphenyl-methyl bromide (77-2) that was used to prepare losartan to afford (78-4). The nitrile group is in this case converted to the tetrazole by means of tributyltin azide, a reagent that involves milder conditions than the traditional acidic medium used to generate hydrazoic acid. Thus, treatment of (78-4) with the tin reagent affords irbesartan (75-5) [82]. [Pg.285]

The presence of the propionamide fragment in the stmcture of the anti-inflammatory agent broperamole (125-1) is reminiscent of the heterocycle-based NSAID propionic acids. The activity of this agent may trace back to the acid that would result on hydrolysis of the amide. Tetrazoles are virtually always prepared by reaction of a nitrile with hydrazoic acid or, more commonly, sodium azide in the presence of acid in a reaction very analogous to a 1,3-dipolar cycloaddition. A more recent (and safer) version of the reaction noted later (see losartan, 77-4) uses tributyltin azide. In the case at hand, reaction of the anion of mefa-bromobenzonitrile (125-1) with sodium azide and an acid affords the tetrazole (125-2). Condensation of the anion from that intermediate with ethyl acrylate leads to the product from Michael addition saponiflcation gives the corresponding carboxylic acid (125-3). This is then converted to the acid chloride reaction with piperidine affords broperamole (125-4) [136]. [Pg.313]

Lead azide [Pb(N3)2] (LA) is a salt of hydrazoic acid (N3H, highly poisonous) and is prepared by reacting solutions of sodium azide and lead acetate or nitrate. This exists in two forms the a form (orthorhombic and stable) and P form (monoclinic) which has a tendency to revert back to the a form. The P form is much more sensitive. The two forms differ in their rate of decomposition when heated. Crystalline LA is stored in dry conditions because it becomes more sensitive when... [Pg.76]


See other pages where Hydrazoic acid, preparation is mentioned: [Pg.59]    [Pg.62]    [Pg.59]    [Pg.62]    [Pg.59]    [Pg.62]    [Pg.59]    [Pg.62]    [Pg.113]    [Pg.267]    [Pg.462]    [Pg.83]    [Pg.84]    [Pg.27]    [Pg.771]    [Pg.701]    [Pg.40]    [Pg.223]    [Pg.516]    [Pg.380]    [Pg.113]    [Pg.521]    [Pg.614]    [Pg.615]    [Pg.151]    [Pg.644]   
See also in sourсe #XX -- [ Pg.64 , Pg.65 ]




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Hydrazoic acid

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