Azide reaction of

Arenesulphinylation 264 Arenesulphinylethanes, synthesis of 267 2-Arenesulphonyl-3-aryloxaziridines, as oxidizing agents 254 Arenesulphonyl azides, reactions of 641 At-Arenesulphonyliminopyridinium betaines, mass spectra of 160-162 Arenesulphonyl radicals 215, 1091 Aryldiazonium salts, reactions of 280, 281 Aryl(methylsulphinyl)(methylthio)alkenes, synthesis of 614... 

Protocol 6 shows the chemoselective reduction of the more electrophilic aromatic azide. Reaction of the resultant IMP with phenyl isocyanate gives the carbodiimide, which upon heating in a sealed tube, undergoes cyclization. 

Azides are generally stable in the presence of bases and nucleophilic displacement of the azido group is uncommon, but displacements have been observed on a few vinyl azides. Reaction of j8-azidovinyl phenyl ketone 73 (R = H) with piperidine gave phenyl -2-piperidino-vinyl ketone (119) and reaction of the same azide with sodium hydroxide in aqueous methanol gave the dimethyl acetal 120 . 

Thallium(i) azide and iodine converted 5a-cholest-2-ene into a mixture of three isomeric iodo-azides. Reaction of either a 17-methyleneandrostane (77) or a 17-methylandrost-16-ene (78) with thallium triacetate gave mixtures of the allylic acetates (79), (80), and (81). Oxymercuration-demercuration was more selective in giving, after acetylation, the 16/8-acetoxy-17-methylene compound (80) as the main product. 

Thiem et al. have described [75,76] the synthesis of hexopyranosyl imides of gluco and manno configuration starting from 0-protected glycosylamines available by reduction of glycosyl azides. Reaction of 52, 53 with succinic anhydride followed by a cycHzation reaction of the corresponding... 

The hydroxylation of the unsaturated lactone (107) by the treatment of its potassium enolate with the Davis oxaziridine afforded the a-hydroxy lactone (108) as a single diastereoisomer (Scheme 6) <92TL67l>. Evans et al. have examined the diastereoselection of the azidation reaction of the potassium enolate derived from the unsaturated lactam (109). The product (110) was formed in only moderate yield, and as a 1 1.4 mixture of diastereoisomers (Scheme 6) <92TL6859>. 

The (3-azidation reaction of triisopropylsilyl enol ethers (Schemes 3.186 and 3.187) has been effectively utilized in organic synthesis [563-565]. Magnus and coworkers have developed a mechanistically different enone synthesis that involves treatment of (3-azido TIPS enol ethers 469 and 471 with fluoride anion to effect desilylation and concomitant (3-elimination to give an a,(3-enone [563]. Alternatively, the (3-azido group in 469 or 471 can be ionized with MesAl or Me2AlCl and the intermediate enonium ion trapped by various nucleophiles, such as an allylstannane, electron-rich aromatics and trimethylsilyl enol ethers, to give various (3-substituted TIPS enol ethers. Reduction of the (3-azido TIPS enol ether provides access to the synthetically useful p-amino TIPS enol ethers [563]. 

Other reactions that have been applied in the Ugi postmodification strategy are the aza-Wittig reaction [80-84] and copper-catalyzed processes [85, 86], More recently, Domling and coworkers have developed a new approach for the synthesis of polycyclic compounds via Ugi MCR followed by a Pictet-Spengler reaction [87-89]. In 2011, apro-tocol for the rapid access to quinolin-2-(l//)-one scaffold was reported by a sequential 4-component Ugi-Knoevenagel condensation [90]. Hulme et al. have introduced a one-pot, two-step protocol for large-scale production of libraries of novel peptidomimetic-like fcM-pyrrolidinone tetrazoles via the Ugi-3CR-azide reaction of tethered keto ester methyl... 

Benzenesulfonyl azide Reactions of N-heterocyclics with sulfonic acid azides N-Condensed 1,2,3-triazoIe ring... 

The first application of the alkyltrifluoroborate salts was the conversion into alkyldihaloboranes by silyl hahdes and subsequent reaction with alkyl azides [77]. An example of a usefid synthesis was the preparation of (S)-2-phenylpyrrolidine (141) (Scheme 8.32). (S)-DICHED (3-bromopropyl)boronate (13S) was converted into the 3-azido derivative 136 at reflux temperature under phase-transfer conditions. The usual reaction with (dichloromethyl)lithium followed by phenylmagnesium bromide to form DICHED ester 137 was followed by treatment with potassium bifluoride in aqueous methanol to provide the alkyltrifluoroborate salt 138. Neither boronic esters nor alkyltrifluoroborate salts react with alkyl azides. Reaction of 138 with trimethylsi-lyl chloride yielded (S)-2-phenylpyrrolidine (141), but reaction with silicon tetrachloride proved much faster and more efficient. At first it was thought that the intermediates 139 and 140 were probably difluoroboranes in accord with literature precedent [76], but careftil reinvestigation has revealed that reaction of alkyltrifluoroborate salts with silicon tetrachloride in coordinating solvents yields alkyldichloroboranes [78]. 

Zhang and coworkers recently reported on the nse of a cobalt (II) tetraphenyl porphyrin complex, Co(TPP), as a catalyst for the intra-molecnlar amination of snUbnyl azides. Their work builds on early studies where Cenini and coworkers used Co(TPP) for the amination of benzylic C—H bonds with aryl azides. Reactions of primary, secondary, and tertiary sulfonyl azides with Co(TPP) in chlorobenzene in the presence of molecular sieves and under an inert atmosphere at SO C gave the desired sultams 296-301 in high yield. The authors noted that tertiary C—H bonds reacted to give higher product yields then than secondary and primary C—H bonds, respectively, in the formation of live-membered heterocyclic ring structures. 

Reactions of hemoglobin with cyanide and the magnetic properties of the cyanide complex. Equilibrium constant of the reaction. Reaction of cyanide with catalase and peroxidase. Magnetic properties of products. Reaction of hemoglobin with fluoride and its relation to the reaction with hydroxyl ion. Equilibrium constants for reactions of fluoride with cytochrome c, catalase, and peroxidase. Magnetic effects associated with these reactions. Velocity of reaction of ferrihemoglobin with hydro-sulfide. Magnetic properties of product. Reactions with azide. Reactions of hydroxyl ion with various heme proteins. Reconsideration of all the results in connection with possibility of interactions between hemes. 

Takeuchi H, Adachi T, Nishiguchi H, Itou K, Koyama K (1993) Direct aromatic amination by azides reactions of hydrazoic acid and butyl azides with aromatic compounds in the presence of both trifluoromethanesulfonic acid and trifluoroacetic acid. J Chem Soc Perkin Trans 1 867-870... 

A diastereodivergent azidation reaction of enynes was achieved by Wan, Li, and co-workers very recently (Scheme 7.58) [125]. In this transformation, the diastereoselectivity was switched by changing the transition metals and the ligands. The Mn(III)-mediated radical cyclization/azidation cascade of 1,7-enynes afforded fran -fused pyrrolo[3,4-c]quinolinones 82, whereas the Cu(II)/bipyridine system provided cw-products 83. 

Stereospeciflc Conversion of Alcohols to Azides. Reaction of an alcohol with DPPA, Triphenylphosphine, and Diethyl Azodi-carboxylate forms the corresponding azides in 60-90% yields. The stereospeciflc nature of this reaction permits the conversion of A -sterols such as 3p-cholestanol exclusively to the 3a-cholestanyl azide in 75% yield. This synthesis is clearly superior to the alcohol - tosylate -> azide route which is longer and also prone to competing elimination reactions. 

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