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13.13.1.4.3 Rearrangement of Substituents

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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Meee eeee ee eeeeeeeeeeeee ee eeee eeeeeeee ee 8-eeeeeeeeeee 8-(eeeeeeeeeee)-8M-8,8,8-eeeeeeeee (Meeeee 888). Mee eeeeeee, eeeeee 888 eee 888 (M8=M) eee eeeeeeeeeeeeeeee eeee eeeeee ee eeeeeeee eeeeeeeee ee 88°M. Mee eeeeeeeeeee eeeeeeee eeeeeee ee eee eeeeeeeeee eeeeeeeeee ee eee M8 eeeeeeeeeee, eeeeeeee 888 eeee M8 ee eeeee, eeeeee, eee 8-eeeeeeeeeeeee, eee 888 eeee M8 ee 8-eeeeeeeeeeee eee 8-eeeeeeeeeee.[‌888‌] Me eeeeeeeeeee eeeeeeeeeee ee eeee eeeeeeeeeeeee ee eee eeeeeeeee ee 8-eeeee-8M-8,8,8-eeeeeeee-8-eeeeeeeeeeeee 888 eeee 8-eeeeee-8M-8,8,8-eeeeeeee-8-eeeeeeeeeeee (888, M8=M).[‌888‌] Meee eeee ee eeeeeeeeeeeee ee eeee eeeeeee ee eee eeeeeeeeee ee 8-eeeeee-8M-8,8,8-eeeeeeee-8-eeeeeeeeeeeee 888 (M8=Me, Me) eeee 8-eee-eeeeeeeeeee 8-eeeee-8M-8,8,8-eeeeeeeee 888 (M8=Me, Me).[‌888‌]

Meeeee 888 Meeeeeeeeeeee ee 8-Meeeeeeeeee 8-(Meeeeeeeeee)-8M-8,8,8-eeeeeeeee[‌888‌,‌888‌]

Meeeeee eee eeeeeee ee eeeeeeeee eee eeeee eeeeeeeeeee 888 (M8=M; M8=MM8, MMMe, MM) ee eeeeeeeee ee 888,[‌888‌] eeeeeeeeeeeeeee 888 (eeeeeeee eeee eeeeeeee 888) eee eeeeeeeee eeee eeeeeeeeee 888 (Meeeee 888). Meeeeeeee, eeeeeeeeeeeeeee 888 (M8=MMMe) eee eeeee 888 (M8=MM) eee eeeeeeeee eeee eeeeee 888.[‌888‌] Meeeeeee 888 [eee 8-eeeeee, 8-(8-eeeeeeeeeeee), eee 8-(8-eeeeeeeeeeeee) eeeeeeeee] eee eeeeeeeee eeee eeeeeeeeeeee ee eeee 888 (M8=Me, Me) ee eeeeeeee eeee eeeeeeeeeee ee eeeeeeeeee eeeeeeee ee eeeeeeeeeeeee ee eee eeeeeeeee eeeeee ee eeeeeee eeeee eeeee eeeeeee eeeeee.[‌888‌]

Meeeee 888 Meeeeeeeeeeee ee 8-Meeeee-8M-8,8,8-eeeeeeeee Meeeeee e Meeeeeeee ee Meeee Meeeeeee ee eee 8-Meeeeeee[‌888‌]

Meeeeee eeeeeeeeeee eeee ee eeeeeeeeeeeee ee 8,8,8-eeeeeeeee eeeeeeeeeee ee eee eeeeeeeee ee eeeee eeeeee eeeeeee eeeeeeeee. Meee ee eee e eeee eeeeee eeeeeeeeeeeeee, eee eeee eeeeeeee eeee eeee eeeeeeee.[‌888‌,‌888‌,‌888‌] Meeeeeee 888, eee eeeeeee, eeeeeeeeee ee 888 eeee eeeeeee eeee eeeee eeeeeeeeeee (Meeeee 888).[‌888‌,‌888‌]

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%).

References


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