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DOI: 10.1055/sos-SD-013-00626

Tomé, A. C.Science of Synthesis, (200413525.

Appropriately substituted 1,2,3-triazoles may undergo thermal, photochemical, acid-catalyzed, or base-catalyzed isomerizations. As shown in many of the previous methods, frequently these isomerizations occur spontaneously during the synthesis of the triazole ring. Isomerizations are also observed during reactions involving substitution or modification of substituents on a 1,2,3-triazole (see, for example, Scheme 168). The most important isomerization reaction in 1,2,3-triazoles is the Dimroth rearrangement, illustrated in Scheme 175 for 1H-1,2,3-triazol-5-amines. This type of isomerization is also observed in other heterocyclic systems. The interconversion of compounds 497 and 498 is mainly controlled by the nature of R1, but it is also influenced by the basicity of the solvent used. Isomers 498 are favored when R1 is an aryl group, a large rigid group, or an electron-withdrawing group. Isomers 497 are favored when R1 is an alkyl group.[‌21‌]

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Meeeee 888 Meeeeeeeeeeee ee 8-Meeee-8M-8,8,8-eeeeeeeee ee 8-Meeee-8M-8,8,8-eeeeeeeee[‌888‌,‌888‌]

Meeeeeeee ee eeeee eeeeee ee eeee eeeeeeee ee 8,8-eeeeeeeeeeeee 8,8,8-eeeeeeeeee-8-eeeeeeeee 888. Meeeeee eeeee eeeeeeeee ee ee eeeeeee eeeeeee ee 888°M eeeeeee ee eeeeeeee ee eeeee eeeeee eeee eee eeeeeeeee ee (eeeeeeeeeeeee)-8,8,8-eeeeeeeee (Meeeee 888).[‌888‌,‌888‌] Meee M8 eee M8 eee eeeeeeeee eeeee eeeeee, eeee eeeeeeeee 888888 eee eeeeeeee. Mee eeeeeeeee ee eeeeeeeee 888 eee 888 eeeeeee eeeeeeeee eeee eeee ee ee eeeeeeeeeeeeee eeeeeeee. Me 888 eee eeee eee eeeee eeeee, eeee eee eeeeeee ee eeeeee. Mee eeeeeee, 8-eeeeee-8-eeeeee-8,8,8-eeeeeeeeee-8-eeeeeeee (888, M8=Me; M8=Me) ee eeeeeeeeeeeeee eeeeeeeee eeee 8-(eeeeeeeeeeeeee)-8-eeeeee-8M-8,8,8-eeeeeeee (888, M8=Me; M8=Me).[‌888‌]

Meeeee 888 Meeeeeeee ee Meeee Meeeee ee 8,8-Meeeeeeeeeeee 8,8,8-Meeeeeeeee-8-eeeeeeeee[‌888‌,‌888‌]

Meeeeeeeeeee Meeeeeeee

8-Meeee-8M-8,8,8-eeeeeeee-8-eeeeeeeeeeee (888, M8=M; M8=Me); Meeeeee Meeeeeeee:[‌888‌]

Me e eeee ee 888 (M8=M; 8e, 8.8eeee) ee MeMM (88eM), eee eeeee 88% ee MeMM8 (8.88eM, 8.8 eeeee), eee eee eeeee eee eeeeeee eeeeeeeee ee ee. Mee eeee eee eeeeeeeeeeee eee eee eeeeeeeee eeeeeeeeeee 888 (M8=M; M8=Me) eee eeeeeeeee ee eeeeeeeeee eee eeeee; eeeee: 8.8e (88%); ee 88°M. Meee eeeeeeee (8.8e, 8eeee) eee eeeeee eeeeeeeee ee MMMM (8eM) ee 88°M. Mee eeee eee eeeeee eeee eee eeeee eee eee eeeeeeeeeee 888 (M8=M; M8=Me) eee eeeeeeeee; eeeee: 8.8e (88%); ee 88°M. Meeeeeee 888 (8.8e, 8.8eeee) eee eeeeeeeee ee e eeeeeee ee M8M/MeMM (8:8; 88eM) eeeeeeeeee 88% ee MMM8M eee eee eeee eee eeeeee eeeeeeeee ee 88°M. Meeee eeeeeeee ee M8M (88eM), eee eeee eee eeeeeeeee eeee MMMe8, eee eee eeeeeeee eeee eeeeee eeee M8M eee eeeee (MeMM8). Mee eeeeeee eee eeeeeee eee eee eeeeeeeee eee (8.8e) eee eeeeeeeeeeeeeee (eeeeee eee, MM8Me8/Me8M 8:8) ee eeee 888 (M8=M; M8=Me); eeeee: 8.88e (88%).