Replacement of azido group

I. 1.8.2. Replacement of Azido Groups with Fluorine in the Nitrosative Decomposition... 

There are individual cases of replacement of other groups in substituted pyridazine iV-oxides, such as the substitution of methoxy or ethoxy groups with amino or hydrazino groups, and replacement of an azido group with a methoxy, ethoxy, or benzyloxy group... 

Introduction of a 2 -hydroxyl group in the j8-configuration to AZT (3 -Az-ara-T) led to an inactive compound. Reduction of the azido moiety of AZT to an amino group (3 -NH2-ddT) also abolished activity. Efforts to replace the azido group with a variety of... 

The benzylic hydrogen atom of alkylarenes is replaced by the azido group on treatment with trimethylsilyl azide in the presence of 2,3-dichloro-5,6-dicyano-l,4-benzoquinone subsequent hydrogenation yields amines (e.g. equation 5)31. 

In some of the following examples, the terminal amino group of the substrate is initially protected or even replaced by an azido group ... 

Such cyclizations have been used extensively, especially to prepare hydropy-razines. The amino group of the substrate may be replaced by an azido group or it may be used (especially for chiral syntheses) in a protected form In the latter case, deprotection is usually done prior to cyclization albeit in a one-pot sequence the ester group of the substrate may be replaced by a terminal lactonic grouping.813 The following examples illustrate some such possibilities ... 

The most common "monovalent nitrogen groups which can be substituted by fluorine are the nitro (NO2). azido (N3), triazo (N = NNR2), and amino (NH2) groups. Replacement of the amino group is facilitated by transformation to either the corresponding activated diazo-nium salt (N2 by diazotization. or by quaternization to the ammonium salt (NRj" X ). 

C. Replacement of Halogeno Substituents by Hydrazino, Azido, and Amido Groups... 

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