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Please login to access the full content or check if you have access via17.5.2.2.1 Method 1: Photolysis Reaction of Azidopyridines with Nucleophiles
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Herr, R. J., Science of Synthesis, (2004) 17, 948.
Photolysis reactions of azidopyridines have been shown to provide 1,3-diazepines (Scheme 19). Reisinger and co-workers showed that irradiation of 2-azidopyridine (62), which is in equilibrium with the fused tetrazole 63, forms a fleeting nitrene species which inserts intramolecularly to provide an intermediate cyclic carbodiimide. In situ trapping of this intermediate with nucleophiles provides 2-substituted 1,3-diazepines as either 1H- or 5H-tautomers, depending on the nucleophile and on the substitution around the pyridine substrate.[72–74] When simple alcohols are used as nucleophiles, 1H-1,3-products 64 predominate, whereas the use of secondary amine nucleophiles leads to 5H-1,3-products 65 in most cases. Another research team has shown that 6-chloropyridin-2-amines may be diazotized and photolyzed with alcohol and amine substrates to provide 2,7-disubstituted 5H-1,3-diazepines in good yields.[75] 2,4-Disubstituted 3-azidopyridines 66 may also be irradiated in the presence of sodium methoxide to provide 4-methoxy-5H-1,3-diazepines 68 via intermediate 67 in moderate yields.[76]
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References
[72] | Meeeeeeee, M.; Meee, M.; Meeeeee, M., M. Meee. Mee., Meeeee Meeee. 8, (8888), 8888. |
[73] | Meee, M.; Meeeee, M.; Meeeeee, M., M. Meee. Mee., Meeeee Meeee. 8, (8888), 8888. |
[74] | Meeeeeeee, M.; Meeeeee, M., M. Meee. Mee., Meee. Meeeee., (8888), 888. |
[75] | Meee, M.; Meeeeeee, M.; Meeeee, M., M. Meeeeeeeee. Meee., (8888) 88, 8888. |
[76] | Meeeeeeee, M.; Meeeee, M.; Meeeeeee, M., Meee. Meeee. Meee., (8888) 88, 8888. |
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- 8.Meeeee-Meee, (8888) M 8e, 888.
- 8.Meeeee-Meee, (8888) M 88e, 888.
- 8.Meeeee-Meee, (8888) M 8e, 888.
- 8.Meeeee-Meee, (8888) M 8e, 888.