III. Azo Compounds

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Azo compounds, in particular 2,2'-azobis(isobutyronitrile), are ubiquitous initiators in radical reactions, but they rarely participate in these reactions in other ways. One reaction that includes an azo compound in a role other than that as an initiator is shown in eq 17, where the imine 11 is produced by reaction of a carbohydrate radical with an azo compound.^52,53 The dimer 12 is a suggested intermediate in the proposed mechanism for this reaction, which is pictured in Scheme 7.^52,53 After radical reaction is complete, the imine 11 can be hydrolyzed to produce an aminodeoxy sugar.

II15(17).png

It is also possible to synthesize an azo compound in a radical reaction. Such a compound is formed when a carbohydrate radical, generated from a deoxyiodo sugar, adds to a diazonium salt (eq 18).⁵⁴ The propagation steps for a proposed mechanism for this reaction are shown in Scheme 8.⁵⁴

II15(18).png