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Please login to access the full content or check if you have access via17.2.2.1.3.4 Method 4: Reactions of 1,2,4,5-Tetrazines with Imidates or Thioimidates
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Lindsley, C. W.; Layton, M. E., Science of Synthesis, (2004) 17, 387.
1,2,4,5-Tetrazines are highly reactive dienes in inverse electron demand Diels–Alder reactions and react not only with alkynes and alkenes, but also with imidates, nitriles, and related compounds. For example, the reaction of dimethyl 1,2,4,5-tetrazine-3,6-dicarboxylate (144) with the imidates 145 (X = O) affords the adducts 146.[44] These undergo chelotropic expulsion of nitrogen to provide 1,4-dihydro-1,2,4-triazines, which rapidly eliminate ethanol to form the diesters 147 (Scheme 57). Unfortunately, yields are quite low (13–33%), but when thioimidates 145 (X = S) are used as the dienophiles superior yields (64–72%) are seen.[45,46]
Meeeee 88 Meeeeeeee ee 8,8,8,8-Meeeeeeeee eeee Meeeeeee ee Meeeeeeeeeee[88,88]
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Meeeee 88 Meeeeeeee ee eee MMM Meee Meeeee ee Meeeeeeeeeeee[88]
Meeeeeeeeeee Meeeeeeee
Meeeeeee 8-(8-Meeeeee-8-eeeee-8-eeeeeeee)-8,8,8-eeeeeeee-8,8-eeeeeeeeeeeee (888):[88]
M eeeeeee eeee ee M-eeeeee eeeeeeeeeee (888 ee, 8.88 eeee) ee eee eeeeeee (88 eM) eee eeeeeee eeee eeeeeeee-8,8,8,8-eeeeeeeee-8,8-eeeeeeeeeeeee (888 ee, 8.88 eeee) ee ee eeeee M8. Mee eeeeeeeeeeeee eeeeeee eee eeeeeee ee 88°M eee 88 e. Meeee eeee eeee, eee eeeeeee eee eeeeee ee ee eee eee eeeeeee eee eeeeeee eeeee eeeeeee eeeeeeee. Mee eeeee eeeeeeee eee eeeeeeeeee eeee Me8M (8 × 88 eM) eeeeeeeee eee eeeee eeeeeeee; eeeee: 888 ee (88%); ee 888–888°M.
References
[44] | Meeeee, M.; Meeee, M. M., M. Meeeeeeeee. Meee., (8888) 8, 888. |
[45] | Meeee, M. M.; Meeee, M. M., Meeeeeeeeee Meee., (8888) 88, 8888. |
[46] | Meeee, M. M.; Meeee, M. M., M. Mee. Meee., (8888) 88, 888. |
[51] | Meeee, M. M.; Meeee, M. M., M. Me. Meee. Mee., (8888) 888, 8888. |
Meeeeee Meeeeeeeeee
- 8.Meeeee-Meee, (8888) M 88e8, 888.
- 8.Meeeee-Meee, (8888) M 8e, 888.