Sodium azide, also

Sodium azide also adds to olefins of this t3rpe to give w-triazoles in fairly good yields. A mechanism involving nucleophilic displacement of the substituent X by azide, followed by cyclization of the vinyl azide in the presence of azide ions, has been suggested. An alternative mechanism involves conjugate addition of azide to the double bond, cyclization of the resulting anion, and aromatization. 

Reaction of vinyl phosphonium salts with sodium azide also yields triazoles via triazoline intermediates by elimination of triphenylphosphine (Scheme 130).418... 

Clathrin-mediated endocytosis can be blocked by several pharmacologic inhibitors, including the antipsychotic drug chlorpromazine (Thorazine), the natural product ikarugamycin, and the antiviral drug amantadine. The metabolic poisons phenylarsine oxide and sodium azide also block CMF but additionally inhibit protein synthesis. Culture of cells under conditions that deplete potassium or calcium, treatment of cells with hypertonic sucrose, or acidification of the cytoplasm by addition of... 

The reaction of the chloronucleoside (120) with sodium azide also gave a mixture (121 and 122) preponderating in the product of attack at C-3, that is, 9-(3-azido-3-deoxy-2-(S-ethyl-2-thio-/3-D-arabinofuranosyl)adenine... 

The range of nucleophiles usable in this substitution reaction was very broad. Carbon nucleophiles such as acetoacetate, diethyl malonate, 3-methyl-2,4-pentanedione gave alkylated products in 98%, 94% and 86% yield, respectively. Nitrogen containing nucleophiles (hydrochloride salts of amino acids) gave Al-allylated products in 90-98% yield. Sodium phenylsulfmate and sodium azide also reacted in high yields (86% and 79%, respectively). The catalyst could be readily recovered and re-used. No loss of activity was observed over 7 continuous runs. 

The addition of preservatives is also recommended, e.g., merthiolate at a concentration of 1/10,000, or sodium azide (0.02"C0.1%). Care is necessary in using both preservatives. Sodium azide also inhibits some ELISAs, and attention to its final concentration in any assay is necessary. 

Two further syntheses of (+)-epiquinamide (2104), another of the (—)-enantiomer e t-2104 and one of the racemic alkaloid also pre-date the clarification of the natural product s absolute configuration. The route by Tong and Barker used (S)-(—)-pipecohnic acid (192) as chiral precursor (Scheme 267).After Boc protection of the amine and conversion of the carboxylic acid into the aldehyde 2121, diastereoselective addition of the lithium anion of TBS-protected propargyl alcohol gave mainly the (R)-alkynol (—)-2122 (69%) as well as the separable (S)-product, which was isolated as the cyclic carbamate (—)-2123 (5%). Attempts to invert the configuration of 2122 by treating its mesylate with sodium azide also... 

Boron mixed with an oxidizer is used as a pyrotechnic. This ordnance appHcation for missiles and rockets is predominandy military. However, boron is also used in air bags, placed in automobiles as safety devices, for initiating the sodium azide [26628-22-8] which fiHs the bag with nitrogen (13). Other boron compounds are also used in the air-bag pyrotechnic appHcation. 

Sodium azide [26628-22-8] M 65.0, m 300°(dec, explosive), pK 4.72 (for HN3). Crystd from hot water or from water by the addition of absolute EtOH or acetone. Also purified by repeated crystn from an aqueous solution saturated at 90° by cooling it to 10°, and adding an equal volume of EtOH. The crystals were washed with acetone and the azide dried at room temperature under vacuum for several hours in an... 

The polymer (SN)x may also be made in a two-step process using azide reagents. Thus the reaction of S2CI2 with sodium azide in... 

The use of azide reagents is also important for the synthesis of cyclic sulfur(VI)-nitrogen systems. The reaction of SOCI2 with sodium azide in acetonitrile at -35°C provides a convenient preparation of the trimeric sulfanuric chloride [NS(0)C1]3 (Eq. 2.16). " Thionyl azide, SO(N3)2 is generated by the heterogeneous reaction of thionyl chloride vapour with silver azide (Eq. 2.17). This thermally unstable gas was characterized in situ by photoelectron spectroscopy. The phenyl derivative of the six-membered ring [NS(0)Ph]3 can be prepared from lithium azide and PhS(0)Cl. ... 

Sulfanuric halides contain the characteristic group -N=S(0)X- (X = Cl, F). Unlike the isoelectronic cyclophosphazenes (NPClajx (x = 3-17), " only six-membered rings have been well characterized. The sulfanuric halides are colourless solids (X = Cl) or liquids (X = F), which are stable in dry air. Sulfanuric chloride [NS(0)C1]3 is best prepared by treatment of SOCI2 with sodium azide in acetonitrile at -35°C (Eq. 8.16). It may also be obtained as a mixture of a- and yS-isomers in a two-stage reaction from H2NSO3H and PCls. The fluoride [NS(0)F]3 is formed as a mixture of isomers by the fluorination of [NS(0)C1]3 with Sbp3. ... 

As shown by Oliveri-Mandalli,and by Lieber et al., 5-sub-stituted-amino-l,2,3,4-thiatriazoles are also formed by reaction of isothiocyanates with hydrazoic acid. When sodium azide is used instead of the free acid the isomeric mercaptotetrazoles are formed. 

Reaction of 5-chloro-l,2,4-triazolo[l,5-c]pyrimidines (165) with sodium hydroxide, thiourea, or hydrazine hydrate (79AJC1585) or with sodium azide (85EUP152841) also caused the displacement of the chlorine atom to... 

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. 

Far superior yields of l-(arylsulfonyl)-l//-azepines 16 are now available by a one-pot synthesis involving the action of sodium azide on an arylsulfonyl chloride under solid-liquid phase-transfer conditions which prevents the formation of acidic sulfonamides and, hence, the ring-contraction process.75 This procedure also has the advantage of avoiding the use of high pressures and the isolation and handling of the potentially explosive sulfonyl azides. 

Note Alternatively 1% solutions of starch, iodine and sodium azide may be sprayed successively onto the chromatogram in that order [4, 9], Other orders of application are also referred to in the literature [1, 2, 17] and sometimes the starch is also worked into the layer so that it is not necessary to spray with it [11, 12]. Sometimes the treatment of the chromatograms with starch solution is omitted [5,6,14] in such cases colorless chromatogram zones appear on a brown layer background. 

The aziridine aldehyde 56 undergoes a facile Baylis-Hillman reaction with methyl or ethyl acrylate, acrylonitrile, methyl vinyl ketone, and vinyl sulfone [60]. The adducts 57 were obtained as mixtures of syn- and anfz-diastereomers. The synthetic utility of the Baylis-Hillman adducts was also investigated. With acetic anhydride in pyridine an SN2 -type substitution of the initially formed allylic acetate by an acetoxy group takes place to give product 58. Nucleophilic reactions of this product with, e. g., morpholine, thiol/Et3N, or sodium azide in DMSO resulted in an apparent displacement of the acetoxy group. Tentatively, this result may be explained by invoking the initial formation of an ionic intermediate 59, which is then followed by the reaction with the nucleophile as shown in Scheme 43. 

With a common intermediate from the Medicinal Chemistry synthesis now in hand in enantiomerically upgraded form, optimization of the conversion to the amine was addressed, with particular emphasis on safety evaluation of the azide displacement step (Scheme 9.7). Hence, alcohol 6 was reacted with methanesul-fonyl chloride in the presence of triethylamine to afford a 95% yield of the desired mesylate as an oil. Displacement of the mesylate using sodium azide in DMF afforded azide 7 in around 85% assay yield. However, a major by-product of the reaction was found to be alkene 17, formed from an elimination pathway with concomitant formation of the hazardous hydrazoic acid. To evaluate this potential safety hazard for process scale-up, online FTIR was used to monitor the presence of hydrazoic acid in the head-space, confirming that this was indeed formed during the reaction [7]. It was also observed that the amount of hydrazoic acid in the headspace could be completely suppressed by the addition of an organic base such as diisopropylethylamine to the reaction, with the use of inorganic bases such as... 

Quaternary ammonium azides will displace halogens in a synthesis of alkyl azides. Dichloromethane has been used as a solvent, although this can slowly form diazido-methane which may be concentrated by distillation dining work-up, thereafter easily exploding [1]. An accident attributed to this cause is described, and acetonitrile recommended as a preferable solvent, supported polymeric azides, excess of which can be removed by filtration are also preferred in place of the tetrabutylam-monium salt [2]. A similar explosion was previously recorded when the quaternary azide was generated in situ from sodium azide and a phase transfer catalyst in a part aqueous system [3,4],... 

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