Iodo azides

After drying under vacuum this iodo azide (2.43 g) is suspended in 50 ml of ether and added with stirring to a cold (0°) slurry of lithium aluminum hydride (1.2 g) in 70 ml of anhydrous ether in a 250 ml 3-necked flask (fitted with a reflux condenser and a mechanical stirrer with a Teflon blade). The remaining traces of the iodo azide are rinsed into the reaction flask with three 10 ml portions of ether. The reaction mixture is allowed to warm to room temperature and to stir for a total period of 11 hr. 

The azido mesylate may also be reduced with lithium aluminum hydride in the same manner as previously described for iodo azide reductions. The sodium borohydride/cobalt(II)tris(a,a -dipyridyl)bromide reagent may be used, but it does not seem to offer any advantages over the more facile lithium aluminum hydride or hydrazine/Raney nickel procedures. 

P-Iodo azides can be reduced to aziridines with LiAlH4 or converted to N-alkyl- or N-arylaziridines by treatment with an alkyl- or aryidichloroborane fol-... 

Neither aromatic halogens [232,602] nor nitro groups were affected during the reductions of the azido group [232, 247, 602]. a-Iodo azides gave, on reduction, aziridines or alkenes depending on the substituents and on the reagents used [603]. 

The addition of the pseudohalogen iodine azide (prepared from iodine monochloride and sodium azide in acetonitrile) to methyl 5,6-dideoxy-2,3-di-0-p-tolylsulfonyl-a -L-arabtno-hex-5-enofuranoside has also been achieved a crystalline /3-iodo azide was isolated, in 69% yield, that was stable in the dark, but became colored on exposure to light.130 Brimacombe and coworkers133 have reported the addition of iodine azide to 5,6-dideoxy-l,2-0-isopropylidene-o -D-xy/o-hex-5-enofuranose X-ray crystallographic analysis established that the product is 6-azido-5,6-dideoxy-5-iodo-l,2-0-isopropylidene-/3-L-idofuranose. 

Dehydrohalogenation of the iodo azides yields vinyl azides, and several examples have been reported [50]. (See Table V for examples.)... 

Synthesis of Acyclic Iodo Azides and Vinyl Azides... 

The addition of iodine azide to double bonds gives p-iodo azides.674 The addition is stereospecific and anti, suggesting that the mechanism involves a cyclic iodonium ion interme-... 

Cyclization of haloamines 0-46 Cyclization of amino alcohols 0-61 Cyclization of p-azido alcohols 5-31 From 3-iodo azides... 

The syn addition of iodine azide has been observed with a strained cyclobutene derivative29. Anomalous products were obtained from (i )-cyclooctenes and bicyclic (-E -cyclooctenes30,3I, e.g., 5-7. From 1,5-cyclononadiene and 1,5- and 1,6-cyclodecadiene, stereoselective transannu-lar cyclization occurred, involving acetonitrile (solvent) as the nucleophile to give 8--1032. From 1,3-dienes, benzofuran and A-acylindoles were obtained 1,2- or 1,4-diazides via the corresponding iodo azides (Section 7.2.2.4.). 

Overall yield of the two-step sequence 1. IN3/CH3CN 2. (CH30)3P/CH2CI2. From glycals R = Ac the crude intermediates (iodo azides mixtures) are used in the successive step, whereas from the other glycals the diastereomeric iodo azides are separated by column chromatography. 

The reaction of iodine azide in acetonitrile with cyclic conjugated dienes and polyenes afforded cis-1,2- or cis- 1,4-diazides80 81 in 80-90% yield, via SN2 reaction of the azide ion with the intermediate trans-/)-iodo azides (Section 1.2.2.2). These diazides were not purified, due to their explosive nature, and their stereochemistry was deduced from the H-NMR spectrum of the cycloadducts obtained with dimethyl acetylenedicarboxylate80,81. Instead, the addition of iodine azide to. V-acyl and 7V-sulfonylindole82-83 and benzofuran83 gave mixtures of trans- and cis-2,3-diazides. 

The addition of iodine azide to double bonds gives p-iodo azides. The reagent can be prepared in situ from KI—NaNa in the presence of Oxone -wet alumina. The addition is stereospecific and anti, suggesting that the mechanism involves a cyclic iodonium ion intermediate. The reaction has been performed on many double-bond compounds, including allenes and a,p-unsaturated ketones. Similar reactions can be performed with BrNa and CfNa. 1,4-Addition has been found with acyclic conjugated dienes. In the case of BrNa, both electrophilic and free-radical mechanisms are important, whUe with CIN3 the addi-... 

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. 

Khoukhi, M., Vaultier, M., and Carrie, R., The use of m-iodo azides as primary protected electrophihc reagents. Alkylation of some carbanions derived from active methylene compounds and V,V-dimclh-ylhydrazones. Tetrahedron Lett., 27, 1031, 1986. 

The iodo azide undergoes stereospecific trans dehydrohalogenation to give a vinyl azide, which on photolysis or pyrolysis gives the 2H-azirine. Reduction of the 2H-azirine with lithium aluminium hydride gives the m-aziridine in good yield. 

Pseudohalogen addition reactions reported recently include those of iodine azide (IN3), which readily attacks olefinic steroids (e.g. 139) to give iodo-azides... 

Aziridino-steroids (e.g. 486) are available by reduction of suitable iodo-azides with lithium aluminium hydride, but fewer side-reactions occur if the iodo-azide (484) is first treated with triphenylphosphine, or with a phosphite ester. Loss of nitrogen leads to the iV-phosphonium aziridine derivative (485), which is smoothly reduced by lithium aluminium hydride to give the aziridine. The exact mechanism of nitrogen loss in the first step is uncertain. 

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