1558-23-2Relevant academic research and scientific papers
Three-Component Reaction of 3,3-Difluorocyclopropenes, s-Tetrazines, and (benzo) Pyridines
Nechaev, Ilya V.,Cherkaev, Georgij V.,Boev, Nikolay V.,Solyev, Pavel N.
, p. 1037 - 1052 (2021)
A new three-component reaction leading to 1-α-(pyridyl-2-[1,2,4]triazolyl)-2-alkyl-ethanones has been discovered while studying the reactivity of monosubstituted 3,3-difluorocyclopropenes in an inverse electronic demand Diels-Alder (IEDDA) cycloaddition-cycloreversion sequence with s-tetrazines. The reaction involving the above-mentioned reactants and (benzo)pyridine as a third component results in a complex transformation proceeding in mild conditions in a stoichiometric ratio of reactants and has high functional group tolerance (phenols, amides, ethers, carboxylic acids, ketones, and acrylic esters). As a result, simple pyridines are selectively functionalized at the α-position in good isolated yields. The reaction mechanism includes a rare azaphilic [4 + 2]-cycloaddition step between s-tetrazine and intermediate 1-hydroxyindolizine, suggested after byproduct identification and tracked with a deuterium label. To date, it is only the third known example of skewed azaphilic cycloaddition of tetrazine. The reaction is truly three-component and cannot be effectively performed stepwise.
Catalyst-free photooxidation reaction from 1,4-dihydropyridazine to pyridazine under air
Karaki, Fumika,Kiguchi, Takuto,Itoh, Kennosuke,Sato, Noriko,Konishi, Kazuhide,Fujii, Hideaki
supporting information, (2021/09/16)
In the inverse electron-demand Diels–Alder (iEDDA) reactions between tetrazines and strained alkenes, a mixture of 1,4-dihydropyridazine isomers are formed first, and they are then oxidized to pyridazines. Although the products of these related oxidation processes converge as pyridazines, the oxidation rate is quite low with some substrates. In this study, we revealed that 1,4-dihydropyridazines formed in the iEDDA reactions were oxidized to pyridazines by simply irradiating with an ultraviolet light under an air atmosphere. Our experimental results implied that singlet oxygen was formed in the course of the reactions to oxidize the 1,4-dihydropyridazine molecules.
Selective N1/N4 1,4-Cycloaddition of 1,2,4,5-Tetrazines Enabled by Solvent Hydrogen Bonding
Zhu, Zixi,Glinkerman, Christopher M.,Boger, Dale L.
supporting information, p. 20778 - 20787 (2020/12/22)
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.
Development of a self-immolative linker for tetrazine-triggered release of alcohols in cells
Davies, Sarah,Oliveira, Bruno L.,Bernardes, Gon?alo J. L.
supporting information, p. 5725 - 5730 (2019/06/19)
Bioorthogonal decaging reactions are a promising strategy for prodrug activation because they involve bond cleavage to release a molecule of interest. The trans-cyclooctene (TCO)-tetrazine inverse electron-demand Diels-Alder reaction has been widely applied in vivo for decaging of amine prodrugs, however, the release of alcohol-containing bioactive compounds has been less well studied. Here, we report a TCO-carbamate benzyl ether self-immolative linker for the release of OH-molecules upon reaction with a tetrazine trigger. The benzyl ether linker proved to be highly stable and can rapidly liberate alcohols under physiological conditions upon reaction with tetrazines. The mechanism and decaging yield were systematically examined by fluorescence and HPLC analysis by using a fluorogenic TCO-benzyl ether-coumarin probe and different 3,6-substituted tetrazine derivatives. This study revealed that decaging occurs rapidly (t1/2 = 27 min) and the cycloaddition step happens within seconds (t1/2 = 7 s) with reaction rates of ≈100 M-1 s-1. Importantly, the reaction is compatible with living organisms as demonstrated by the decaging of a prodrug of the antibacterial compound triclosan in the presence of live E. Coli, that resulted in complete cell killing by action of the released "OH-active drug". Overall, this work describes a new linker for masking alcohol functionality that can be rapidly reinstated through tetrazine-triggered decaging.
Tetrazine Assists Reduction of Water by Phosphines: Application in the Mitsunobu Reaction
Polezhaev, Alexander V.,Maciulis, Nicholas A.,Chen, Chun-Hsing,Pink, Maren,Lord, Richard L.,Caulton, Kenneth G.
, p. 13985 - 13998 (2016/09/21)
Reaction of 3,6-disubstituted-1,2,4,5-tetrazines with water and PEt3forms the corresponding 1,4-dihydrotetrazine and OPEt3. Thus PEt3, as a stoichiometric reductant, reduces water, and the resulting two reducing equivalent
CHANNEL PROTEIN ACTIVATABLE LIPOSOMES
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Page/Page column 95; 96, (2014/06/11)
Disclosed is a liposome, comprising a lipid bilayer enclosing a cavity, wherein the bilayer comprises a channel protein releasably linked to an eight-membered non-aromatic cyclic alkenylene group, preferably a cyclooctene group, and more preferably a trans-cyclooctene group. The liposomes are used in a kit comprising the liposome, the liposomal membrane of which comprises a channel protein linked to a Trigger, and an Activator for the Trigger, wherein the Trigger comprises the eight- membered non-aromatic cyclic alkenylene group, and the Activator comprises a diene.
CHEMICALLY CLEAVABLE GROUP
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Page/Page column 80, (2014/06/11)
Disclosed is the use of the reactive components of the inverse electron-demand Diels Alder reaction for chemical masking and unmasking in vitro. This can be applied in complex chemical reactions and, particularly in the synthesis of biomolecules, e.g. on solid supports. The reactice components are a dienophile, particularly a trans-cyclooctene, and a diene, particularly a tetrazine.
ACTIVATABLE LIPOSOMES
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Page/Page column 111, (2014/06/11)
Disclosed are reactive liposome, comprising a lipid bilayer enclosing a cavity, wherein the bilayer comprises a linkage to an eight-membered non-aromatic cyclic alkenylene group, preferably a cyclooctene group, and more preferably a trans-cyclooctene group. The liposomes are use in a kit comprising the liposome linked, directly or indirectly, to a Trigger, and an Activator for the Trigger, wherein the Trigger comprises an eight-membered non-aromatic cyclic alkenylene group, and the Activator comprises a diene.
BIO-ORTHOGONAL DRUG ACTIVATION
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Page/Page column 73, (2014/06/11)
Disclosed is a kit for the administration and activation of a Prodrug. The kit comprises a Masking Moiety linked, directly or indirectly, to a Trigger moiety, which in turn is linked to a Drug, and an Activator for the Trigger moiety. The Trigger moiety comprises a dienophile and the Activator comprises a diene, whereby the dienophile is an eight-membered non- aromatic cyclic alkenylene group, preferably a cyclooctene group, and more preferably a trans-cyclooctene group. The Trigger and the Activator undergo a fast, bio-orthogonal reaction resulting in the release of the Masking Moiety, and activation of the drug.
Click to release: Instantaneous doxorubicin elimination upon tetrazine ligation
Versteegen, Ron M.,Rossin, Raffaella,Ten Hoeve, Wolter,Janssen, Henk M.,Robillard, Marc S.
supporting information, p. 14112 - 14116 (2014/01/06)
Eliminated without a trace: The fastest click reaction, the highly selective inverse-electron-demand Diels-Alder reaction, has been modified to enable selective bioorthogonal release. Thus, the click reaction of a tetrazine with a drug-bound trans-cyclooctene caused the instantaneous release of the drug and CO2 (see scheme). One possible application is the chemically triggered release, and thereby activation, of a drug from a tumor-bound antibody-drug conjugate. Copyright
