A variety of substituted aryl amines were transformed into aryl azides using t-BuONO and moist NaN 3 in t-BuOH in good to excellent yields. Smooth transformation was observed with anilines, having electron withdrawing and donating groups. Both acid-and base-sensitive groups survived the reaction conditions. Azides are versatile intermediates in organic synthesis. 1 A major application of this class of compounds is 1,3-dipolar cycloaddition with an unsaturated reactant to give a variety of five-membered heterocycles. 2 While numerous methods are available for the preparation of aliphatic azides, there is a limited choice for aryl azides. The most straightforward route for the preparation of aryl azides involves diazotization of amines with nitrous acid followed by addition of sodium azide at low temperature. 3 Alternatively, aryl amines have been transformed into aryl azides by treating the former with para-toluenesulfonyl azide in the presence of a Grignard reagent or strong base. 4 Aryl azides have also been prepared from arylmagnesium halides or aryl lithium reagents, generated from aryl halides, and para-toluenesulfonyl azide. 5 The above conversion has also been accomplished under mild condition using a combination of triflyl azide, CuSO 4, and triethylamine. 6 Very recently, the coupling of aromatic and vinyl halides with sodium azide under catalysis with CuI-L-proline was reported to produce aryl/vinyl azides in good to excellent yields. 7 However, all these transformations require either acidic or basic conditions, which are not compatible with many functional groups present in a substrate. This has prompted us to report our results for the same transformation.During the course of our ongoing investigations, we needed a process for the preparation of aryl azides from aryl amines, having acid-and base-sensitive groups. This led us to investigate neutral conditions for the preparation of aryl azides. Here we describe our successful efforts towards this endeavor. Scheme 2Deamination of aryl amines with alkyl nitrite is being carried out in our laboratories as a routine work (Scheme 1). We reasoned that in the presence of a strong nucleophile such as azide, a deamination reaction could be diverted to azide formation (Scheme 2), since aryl amines do undergo diazotization with alkyl nitrite. 8 Scheme 3We chose compound 1 as a model substrate to optimize the reaction conditions for the transformation to azide 2 (Scheme 3). Initially, the reaction was carried out in DMF in the presence of excess t-BuONO 9 (10 equiv) and NaN 3 (5 equiv) at 80°C leading to decomposition of the amine. Although azide formation was observed at room temperature, the reaction was not complete even after 24 hours. Subsequently, reactions were carried out in other solvents such as toluene, chloroform and t-BuOH. Reactions in toluene and chloroform were found to be very slow because of the poor solubility of NaN 3 in these solvents. Addition of a phase transfer catalyst, benzyltriethylammonium bromide, produced a mixture of products. On the...

Azide formation O 0272An Easy Access to Aryl Azides from Aryl Amines under Neutral Conditions. -A one-pot tandem aziridination/substitution method is described for the direct conversion of a variety of aromatic and heteroaromatic amines to the corresponding azides. -(DAS*, J.; PATIL, S. N.; AWASTHI, R.; NARASIMHULU, C. P.; TREHAN, S.; Synthesis 2005, 11, 1801-1806; Chem.

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