- Selective N1/N4 1,4-Cycloaddition of 1,2,4,5-Tetrazines Enabled by Solvent Hydrogen Bonding
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An unprecedented 1,4-cycloaddition (vs 3,6-cycloaddition) of 1,2,4,5-tetrazines is described with preformed or in situ generated aryl-conjugated enamines promoted by the solvent hydrogen bonding of hexafluoroisopropanol (HFIP) that is conducted under mild reaction conditions (0.1 M HFIP, 25 °C, 12 h). The reaction constitutes a formal [4 + 2] cycloaddition across the two nitrogen atoms (N1/N4) of the 1,2,4,5-tetrazine followed by a formal retro [4 + 2] cycloaddition loss of a nitrile and aromatization to generate a 1,2,4-triazine derivative. The factors that impact the remarkable change in the reaction mode, optimization of reaction parameters, the scope and simplification of its implementation through in situ enamine generation from aldehydes and ketones, the reaction scope for 3,6-bis(thiomethyl)-1,2,4,5-tetrazine, a survey of participating 1,2,4,5-tetrazines, and key mechanistic insights into this reaction are detailed. Given its simplicity and breath, the study establishes a novel method for the simple and efficient one-step synthesis of 1,2,4-triazines under mild conditions from readily accessible starting materials. Whereas alternative protic solvents (e.g., MeOH vs HFIP) provide products of the conventional 3,6-cycoladdition, the enhanced hydrogen bonding capability of HFIP uniquely results in promotion of the unprecedented formal 1,4-cycloaddition. As such, the studies represent an example of not just an enhancement in the rate or efficiency of a heterocyclic azadiene cycloaddition by hydrogen bonding catalysis but also the first to alter the mode (N1/N4 vs C3/C6) of cycloaddition.
- Zhu, Zixi,Glinkerman, Christopher M.,Boger, Dale L.
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supporting information
p. 20778 - 20787
(2020/12/22)
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- NOVEL DISUBSTITUTED 1, 2, 4-TRIAZINE COMPOUND
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This invention provides a novel disubstituted 1,2,4-triazine compound or a pharmaceutically acceptable salt thereof, which has an aldosterone synthetase inhibitory activity and is useful for preventing and/or treating various diseases or conditions associated with aldosterone; a method for preparing it; use of it; as well as a pharmaceutical composition comprising it as an active ingredient. A compound of the general formula [I]: wherein RA is, for example, a group of the following formula (A-1): wherein ring A1 is, for example, a cycloalkyl group which may be substituted, and RB is, for example, a monocyclic cycloalkyl group, or a pharmaceutically acceptable salt thereof.
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Paragraph 0305; 0306; 0307; 0308
(2017/03/23)
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- FURTHER INTRAMOLECULAR DIELS-ALDER REACTIONS OF 1,2,4-TRIAZINES. SYNTHESIS OF DIHYDROPYRROLOpyridines
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3-(3-Butynylamino)-1,2,4-triazines undergo intramolecular Diels-Alder reactions to yield 2,3-dihydropyrrolopyridines
- Taylor, Edward C.,Pont, Joseph L.
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p. 379 - 382
(2007/10/02)
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- FURTHER INTRAMOLECULAR REACTIONS OF 1,2,4-TRIAZINES. SYNTHESIS OF FUROPYRIDINES AND DIHYDROPYRANOPYRIDINES
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3-(3-Butynyloxy)- and 3-(4-pentynyloxy)-1,2,4-triazines undergo facile intramolecular Diels-Alder reactions to yield 2,3-dihydrofuro(2,3-b)pyridines and dihydropyrano(2,3-b)-pyridines respectively.The former are readily dehydrogenated with DDQ to furo(2,3
- Taylor, Edward C.,Macor, John E.
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p. 431 - 432
(2007/10/02)
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- 6- AND 7-Aryl-1,2,4-triazolo[4,3-b]-1,2,4-triazines
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This application discloses 6- or 7-(o-, m- or p-substituted-phenyl)-1,2,4-triazolo[4,3-b]-1,2,4-triazines useful as anxiolytic agents.
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- Pharmacologically active substituted 1,2,4-triazines
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Substituted 1,2,4-triazines, compositions thereof and methods of using same are described. The compounds of the invention exhibit a wide range of pharmacological activity including anti-inflammatory, analgesic, anti-pyretic, hypotensive and central nervous system effects.
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