Aziridines sodium azide

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. 

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. 

Highly regioselective opening of epoxides and aziridines with sodium azide and Oxone in aqueous acetonitrile in very high yield was reported (equation 52). ... 

Azidotrimethylsilane, 24, 217 Diazidodiisopropoxytitanium, 217 Sodium azide-Methyltrioctylammonium chloride, 240 Aziridines... 

A stereospecific synthesis of aziridine 266 has been reported by Ittah et al. from arene oxide 1 by treatment with sodium azide, followed by tri-phenylphosphine reaction. The reaction proceeds via a phosphonium hydroxide intermediate (267).157... 

Exposure of sulfolane 261 to sodium azide and mesylation regioselectively afforded mesylate 262, which was transformed into aziridine 263 by a three-step sequence involving azide to amine Staudinger reduction, acetylation, and ring closure. The trans 1,2-diamino derivative 264 was quickly obtained from 263 by azide opening of the aziridine ring, followed by reduction. 

Two isomeric hydroxyl azides, (VIII), and, (IX), were produced when epoxide intermediates were reacted with sodium azide. Both isomers were subsequently converted to the desired aziridine. 

AZIRIDINES Lead tetraacetate. Sodium azide-Triphenylphosphine. Triphenyl-phosphine-Diethyl azodicarboxylate. 

Bromine azide, prepared by different methods, undergoes addition to alkenes stereoselectively by an ionic mechanism 33- 37 (Table 2). Improved yields are obtained by using azidotrimethyl-silane and A-bromosuccinimide (NBS) in the presence of Nafion-FI as catalyst33. Alternatively, A-bromosuccinimide may be added to the mixture of the alkene and sodium azide in dimeth-oxyethane/water34. Aziridines were prepared stereoselectively by reduction of (i-bromo azides with lithium aluminum hydride34. 

The intramolecular aziridination of alkoxycarbonyl azides derived from ( )-5-hydroxymethyl-2(5//)-furanone, via thermal decomposition to nitrenes, gave the tricyclic compound 34 which was successively converted to the bicyclic compound 35. The aziridine ring opening with hydrazoic acid/ sodium azide ion of the aziridines 34 and 35 gives azido lactones 36 with the xylo configuration mixtures of xylo- and (y.w-forms were obtained by partial epimerization in equilibrating conditions and were easily separated60. 

Free amino carboxylic acids65 and their ester derivatives66 can be added to fluoroalkylated alkynes to give amino acid derivatives. Fluoroalkynes and sodium azide afford, after thermal decomposition, the corresponding aziridines.67... 

The treatment of compound 13s with sodium azide in dimethylformamide in presence of ammonium chloride allows ring opening of acetylated aziridine and formation of product 13t. The ring opening reaction is completely regiospecific giving azide 13t as the only product. 

Preparation. By reaction of picryl chloride with sodium azide or by nitration of o- or p-nitroazidobenzene. Like cyanogen azide which see), the reagent (1) reacts with an olefin either to form a Schiff base (2), convertible into the corresponding ketone (3), or to form an aziridine (4). Simple olefins give Schiff bases. The reagent is much safer to handle than cyanogen azide. 

---