- Bridge-Clamp Bis(tetrazine)s with [N]8 π-Stacking Interactions and Azido-s-Aryl Tetrazines: Two Classes of Doubly Clickable Tetrazines
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Click chemistry at a tetrazine core is useful for bioorthogonal labeling and crosslinking. Introduced here are two new classes of doubly clickable s-aryl tetrazines synthesized by Cu-catalyzed cross-coupling. Homocoupling of o-brominated s-aryl tetrazines leads to bis(tetrazine)s structurally characterized by tetrazine cores arranged face-to-face. [N]8 π-stacking interactions are essential to the conformation. Upon inverse electron demand Diels–Alder (iEDDA) cycloaddition, the bis(tetrazine)s produce a unique staple structure. The o-azidation of s-aryl tetrazines introduces a second proximal intermolecular clickable function that leads to double click chemistry opportunities. The stepwise introduction of fluorophores and then iEDDA cycloaddition, including bioconjugation to antibodies, was achieved on this class of tetrazines. This method extends to (thio)etherification, phosphination, trifluoromethylation and the introduction of various bioactive nitrogen-based heterocycles.
- Mboyi, Clève D.,Vivier, Delphine,Daher, Ahmad,Fleurat-Lessard, Paul,Cattey, Hélène,Devillers, Charles H.,Bernhard, Claire,Denat, Franck,Roger, Julien,Hierso, Jean-Cyrille
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Read Online
- Redox potential tuning of s-tetrazine by substitution of electron-withdrawing/donating groups for organic electrode materials
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Herein, we tune the redox potential of 3,6-diphenyl-1,2,4,5-tetrazine (DPT) by introducing various electron-donating/withdrawing groups (methoxy, t-butyl, H, F, and trifluoromethyl) into its two peripheral benzene rings for use as electrode material in a
- Kwon, Ji Eon,Lee, Kyunam,Min, Dong Joo,Park, Hyunji,Park, Soo Young
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- SYNTHETIC SPHINGOLIPID INSPIRED MOLECULES WITH HETEROAROMATIC APPENDAGES, METHODS OF THEIR SYNTHESIS AND METHODS OF TREATMENT
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Small molecules compounds and methods of their synthesis are provided. Formulations and medicaments are also provided that are directed to the treatment of disease, such as, for example, neoplasms, cancers, and other diseases. Therapeutics are also provided containing a therapeutically effective dose of one or more small molecule compounds, present either as pharmaceutically effective salt or in pure form, including, but not limited to, formulations for oral, intravenous, or intramuscular administration.
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Paragraph 0223
(2021/04/02)
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- Synthetic Sphingolipids with 1,2-Pyridazine Appendages Improve Antiproliferative Activity in Human Cancer Cell Lines
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A synthetic sphingolipid related to a ring-constrained hydroxymethyl pyrrolidine analog of FTY720 that was known to starve cancer cells to death was chemically modified to include a series of alkoxy-tethered 3,6-substituted 1,2-pyridazines. These derivati
- Bachollet, Sylvestre P. J. T.,Vece, Vito,Mccracken, Alison N.,Finicle, Brendan T.,Selwan, Elizabeth,Ben Romdhane, Nadine,Dahal, Amogha,Ramirez, Cuauhtemoc,Edinger, Aimee L.,Hanessian, Stephen
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supporting information
p. 686 - 690
(2020/03/04)
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- Iridium complex and organic electroluminescence device using the same
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Provided are: an iridium complex represented by formula (1); and an organic electroluminescent element which uses the iridium complex as a phosphorescent dopant material. The organic electroluminescent element can exhibit good performance, such as reduced driving voltage, improved current efficiency, or a long half-life period.
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Paragraph 0045-0049
(2020/04/17)
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- ADDITIVE FOR IMPARTING LOW HEAT BUILD-UP TO RUBBER COMPONENT
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Provided is an additive for imparting low heat build-up to a rubber component, wherein the additive includes a tetrazine compound represented by general formula (1): (wherein X1 and X2 are the same or different and represent a hydrogen atom or an alkyl, alkylthio, aralkyl, aryl, arylthio, heterocyclic, or amino group; and each of these groups may have one or more substituents), or a salt thereof.
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Paragraph 0194-0198
(2020/08/05)
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- Installation of Minimal Tetrazines through Silver-Mediated Liebeskind-Srogl Coupling with Arylboronic Acids
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Described is a general method for the installation of a minimal 6-methyltetrazin-3-yl group via the first example of a Ag-mediated Liebeskind-Srogl cross-coupling. The attachment of bioorthogonal tetrazines on complex molecules typically relies on linkers that can negatively impact the physiochemical properties of conjugates. Cross-coupling with arylboronic acids and a new reagent, 3-((p-biphenyl-4-ylmethyl)thio)-6-methyltetrazine (b-Tz), proceeds under mild, PdCl2(dppf)-catalyzed conditions to introduce minimal, linker-free tetrazine functionality. Safety considerations guided our design of b-Tz which can be prepared on decagram scale without handling hydrazine and without forming volatile, high-nitrogen tetrazine byproducts. Replacing conventional Cu(I) salts used in Liebeskind-Srogl cross-coupling with a Ag2O mediator resulted in higher yields across a broad library of aryl and heteroaryl boronic acids and provides improved access to a fluorogenic tetrazine-BODIPY conjugate. A covalent probe for MAGL incorporating 6-methyltetrazinyl functionality was synthesized in high yield and labeled endogenous MAGL in live cells. This new Ag-mediated cross-coupling method using b-Tz is anticipated to find additional applications for directly introducing the tetrazine subunit to complex substrates.
- Lambert, William D.,Fang, Yinzhi,Mahapatra, Subham,Huang, Zhen,Am Ende, Christopher W.,Fox, Joseph M.
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supporting information
p. 17068 - 17074
(2019/11/16)
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- CLEAVABLE TETRAZINE USED IN BIO-ORTHOGONAL DRUG ACTIVATION
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Disclosed is an advancement in provoked chemical cleavage. Thereby the invention provides the use of a diene as a chemically cleavable group attached to a Construct, and the use of a dienophile to provoke the release of the Construct by allowing the diene to react with a dienophile capable of undergoing an inverse electron demand Diels Alder reaction with the diene. The invention includes a kit for releasing a Construct CA bound to a Trigger TR, the kit comprising a tetrazine and a dienophile, wherein the Trigger is the tetrazine. The invention also includes the use of the formation of a pyridazine by reacting a tetrazine comprising a Construct CA bound thereto and a dienophile, as a chemical tool for the release, in a chemical, biological or physiological environment, of said Construct.
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Page/Page column 143-144; 148-149
(2018/02/03)
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- PROCESS FOR PREPARING FUNCTIONALIZED 1,2,4,5-TETRAZINE COMPOUNDS
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The present invention relates to a process for the synthesis of 3,6 functionalized 1,2,4,5-tetrazine compounds of formula (I); wherein A and B being the same; and wherein at least one of R1, R1', R2 and R2' and at least one of R10 and R10' is a halogen atom or acetate group; said process comprising reacting the corresponding 1,2,4,5-tetrazine compounds wherein at least one of R1, R1', R2 and R2' and at least one of R10 and R10' is a hydrogen atom with an oxidative reagent in presence of a catalyst.
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Page/Page column 19
(2017/06/29)
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- Tetrazine Assists Reduction of Water by Phosphines: Application in the Mitsunobu Reaction
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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
- Polezhaev, Alexander V.,Maciulis, Nicholas A.,Chen, Chun-Hsing,Pink, Maren,Lord, Richard L.,Caulton, Kenneth G.
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p. 13985 - 13998
(2016/09/21)
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- Ortho-Functionalized Aryltetrazines by Direct Palladium-Catalyzed C-H Halogenation: Application to Fast Electrophilic Fluorination Reactions
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A general catalyzed direct C-H functionalization of s-tetrazines is reported. Under mild reaction conditions, N-directed ortho-C-H activation of tetrazines allows the introduction of various functional groups, thus forming carbon-heteroatom bonds: C-X (X=I, Br, Cl) and C-O. Based on this methodology, we developed electrophilic mono- and poly-ortho-fluorination of tetrazines. Microwave irradiation was optimized to afford fluorinated s-aryltetrazines, with satisfactory selectivity, within only ten minutes. This work provides an efficient and practical entry for further accessing highly substituted tetrazine derivatives (iodo, bromo, chloro, fluoro, and acetate precursors). It gives access to ortho-functionalized aryltetrazines which are difficult to obtain by classical Pinner-like syntheses.
- Testa, Christelle,Gigot, élodie,Genc, Semra,Decréau, Richard,Roger, Julien,Hierso, Jean-Cyrille
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supporting information
p. 5555 - 5559
(2016/05/09)
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- 3,6-Substituted-1,2,4,5-tetrazines: Tuning reaction rates for staged labeling applications
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Cycloaddition reactions involving tetrazines have proven to be powerful bioorthogonal tools for various applications. Conceivably, sequential and selective labeling using tetrazine-based reactions can be achieved by tuning the reaction rate. By varying th
- Wang, Danzhu,Chen, Weixuan,Zheng, Yueqin,Dai, Chaofeng,Wang, Ke,Ke, Bowen,Wang, Binghe
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p. 3950 - 3955
(2014/06/09)
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- A general and efficient entry to asymmetric tetrazines for click chemistry applications
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The importance of click chemistry is widely recognized. Among all the known click reactions, those involving tetrazines represent the fastest click reactions reported and are generating a great deal of interest. However, there is no efficient entry to asymmetric tetrazines and those with strong electron withdrawing groups, which limits the development of this field. Herein, we report a general and efficient entry to asymmetric tetrazines with strongly electron withdrawing groups.
- Wang, Danzhu,Chen, Weixuan,Zheng, Yueqin,Dai, Chaofeng,Wang, Lifang,Wang, Binghe
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p. 171 - 177
(2013/09/02)
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- Novel synthesis of 3,6-disubstituted-1,2,4,5-tetrazine derivatives from hydrazones by using [hydroxyl(tosyloxy)iodo]benzene
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A mild and efficient protocol for the construction of 1,4-dihydro-3,6- disubstituted-1,4-bis(p-toluenesulfonyl)-1,2,4,5-tetrazines from p-toluenesulfonyl hydrazones mediated by [hydroxyl(tosyloxy)iodo]benzene in the presence of pyridine has been developed. This protocol affords the products in good to excellent yields. The corresponding 3,6-disubstituted-1,2,4,5-tetrazines can be easily obtained through one-step N-deprotection of p-toluensulfonyl groups and aromatization by tetrabutyl ammonium fluoride in THF. A mechanism has been proposed.
- Liu, Haixuan,Wei, Yunyang
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p. 4645 - 4648
(2013/08/23)
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- Clicking 1,2,4,5-tetrazine and cyclooctynes with tunable reaction rates
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Substituted tetrazines have been found to undergo facile inverse electron demand Diels-Alder reactions with "tunable" reaction rates.
- Chen, Weixuan,Wang, Danzhu,Dai, Chaofeng,Hamelberg, Donald,Wang, Binghe
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supporting information; scheme or table
p. 1736 - 1738
(2012/03/09)
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- Effect of substituents on redox, spectroscopic and structural properties of conjugated diaryltetrazines - A combined experimental and theoretical study
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Two series of new soluble conjugated compounds containing tetrazine central ring have been synthesized. The three-ring compounds have been synthesized by the reaction of aryl cyanide (where aryl = thienyl, alkylthienyl, phenyl or pyridyl) with hydrazine followed by oxidation of the intermediate product with diethyl azodicarboxylate. The five-ring compounds have been prepared using two pathways: (i) reaction of 5-cyano-2,2′-bithiophene (or its alkyl derivative) with hydrazine; (ii) via Suzuki or Stille coupling of 3,6-bis(5-bromo-2-thienyl)-1,2,4,5-tetrazine with a stannyl or boronate derivative of alkylthiophene. UV-vis spectroscopic properties of the synthesized compounds are strongly dependent on the nature of the aryl group, the position of the solubilizing substituent and the length of the molecule, showing the highest bathochromic shift (λmax > 440 nm) for five-ring compounds with alkyl groups attached to Cα carbon in the terminal thienyl ring. An excellent linear correlation has been found for spectroscopically determined and theoretically calculated (TD-B3LYP/6- 31G*) excitation energies. With the exception of dipyridyl derivative, the calculated lowest unoccupied molecular orbital (LUMO) level of the investigated molecules changes within a narrow range (from -2.63 to -2.41 eV), in line with the electrochemical data, which show a reversible reduction process with the redox potential varying from -1.23 V to -1.33 V (vs. Fc/Fc+). The electrochemically determined positions of the LUMO levels are consistently lower by 0.9 to 1.2 eV with respect to the calculated ones. All molecules readily crystallize. Single crystal studies of 3,6-bis(2,2′-bithien-5-yl)-1,2,4,5- tetrazine show that it crystallizes in a P21/c space group whose structural arrangement is not very favorable to the charge carriers flow within the crystal. Powder diffraction studies of other derivatives have shown that their structural organization is sensitive to the position of the solubilizing substituent. In particular, the presence of alkyl groups attached to C α carbon in the terminal thienyl ring promotes the formation of a lamellar-type supramolecular organization.
- Kurach, Ewa,Djurado, David,Rimarik, Jan,Kornet, Aleksandra,Wlostowski, Marek,Luke, Vladimir,Pecaut, Jacques,Zagorska, Malgorzata,Pron, Adam
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scheme or table
p. 2690 - 2700
(2011/09/20)
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- A novel method for the synthesis of 3,5-disubstituted-(NH)-1,2,4-triazoles from 3,6-diaryl-1,2,4,5-tetrazines
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The reaction of 3,6-diaryl-1,2,4,5-tetrazines and 2-aryl substituted acetonitriles, under basic conditions, leads unexpectedly to 3,5-diaryl-(NH)-1,2,4-triazoles in moderate yields. A mechanism is proposed.
- Haddadin, Makhluf J.,Ghazvini Zadeh, Ebrahim H.
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experimental part
p. 1654 - 1656
(2010/05/19)
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- Synthesis, structures of some unsymmetrical 3,6-disubstituted-1,2,4,5- tetrazines
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(Chemical Equation Presented) A series of new unsymmetrical 3-phenyl-6-benzyl-1,2,4,5-tetrazine derivatives 10a-i were synthesized and characterized by IR, NMR, MS, and element analysis. The structures of 4a, 10c, 10d and 10h were analyzed by X-ray crystallography, which had intermolecular C-H...N, C-H...Cl, C-H...Π and Π...Π H interactions.
- Hu, Wei-Xiao,Xu, Feng
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experimental part
p. 1745 - 1750
(2009/05/31)
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- Microporous material based on π-π Stacking of 1,4-bis(3,6- diphenylpyridazin-4-yl)benzene
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A microporous material constructed by π-π interaction of a twisted H-shape poly-aromatic molecule, 1,4-bis(3,6-diphenylpyridazin-4-yl)benzene (1) was synthesized and X-ray quality crystals were isolated. The intermolecular distances between the various ar
- Kao, Hsien-Chang,Tang, Shang-Wei,Wang, Jau-Shuenn,Wang, Wen-Jwu
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p. 193 - 200
(2008/02/04)
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- Synthesis, structure analysis, and antitumor activity of 3,6-disubstituted-1,4-dihydro-1,2,4,5-tetrazine derivatives
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Fourteen compounds of 3,6-disubstituted-1,4-dihydro-1,2,4,5-tetrazine derivatives were prepared and their structures were confirmed by single-crystal X-ray diffraction and the semi-empirical calculation of PM3 method. This reaction yields the 1,4-dihydro derivatives rather than the 1,2-dihydro derivatives. The central six-membered ring of 1,4-dihydro-1,2,4,5-tetrazine has a chair conformation and therefore is not homoaromatic. Their antitumor activities were evaluated in vitro by SRB method for A-549 and BEL-7402 cells, and MTT method for P-388 and HL-60 cells. The results show that there is one compound which is highly effective against P-388 cells and one compound which is highly effective against HL-60 cells. So it is a kind of compound which possesses potential antitumor activities and is worth to research further.
- Rao, Guo-Wu,Hu, Wei-Xiao
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p. 3702 - 3705
(2007/10/03)
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- Diazocinones: Synthesis and conformational analysis
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1,2,4,5-Tetrazines (prepared from aryl nitriles) condense with isoxazolylcyclobutanones (prepared from 3-benzenesulfonyl-3-vinylcyclobutanol) in methanolic KOH to give conformationally restricted 6-isoxazol-5-yl-6,7- dihydro-5H-[1,2]diazocin-4-ones. The s
- Robins, Lori I.,Carpenter, Richard D.,Fettinger, James C.,Haddadin, Makhluf J.,Tinti, Dino S.,Kurth, Mark J.
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p. 2480 - 2485
(2007/10/03)
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- Synthesis and antitumor activity of s-tetrazine derivatives
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Fifty-five compounds of s-tetrazine derivative including hexahydro-, 1,6-dihydro, 1,4-dihydro-, 1,2-dihydro- and aromatic s-tetrazine were prepared. Their antitumor activities were evaluated in vitro by MTT method for P-388 cell and SRB method for A-549 cell. The results show that there are 9 compounds which in 10-6 μM have more than 50% inhibition rate to A-549 cancer cell growth, and 7 compounds in 10-6 μM have more than 50% inhibition rate to P-388 cancer cell growth. The IC50 of compound 3q for P-388, Bel-7402, MCF-7 and A-549 are 0.6 μM, 0.6 μM, 0.5 μM and 0. 7 μM, respectively. So s-tetrazine derivative is a kind of compound which possesses potential antitumor activities and is worth to research further.
- Hu, Wei-Xiao,Rao, Guo-Wu,Sun, Ya-Quan
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p. 1177 - 1181
(2007/10/03)
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- Tetrazoles: XLIV. Synthesis and chemical properties of 5-substituted 2-triphenylmethyltetrazoles
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Tritylation of tetrazole and its 5-substituted derivatives with triphenylmethyl chloride under conditions of phase-transfer catalysis regioselectively yields the corresponding 5-substituted 2-trityltetrazoles which can be used to protect N-H bonds in nitrogen-containing heterocycles and O-H bonds in primary alcohols. Thermolysis of 2-trityltetrazoles in benzonitrile leads to 3,6-disubstituted 1,2,4,5-tetrazines. Thermal transformation of the same compounds in dodecane follows a radically different mechanism, resulting in formation of difficultly accessible 8,8-diphenylheptafulvenes. The structure of the latter was proved by X-ray analysis.
- Myznikov,Artamonova,Bel'skii,Stash,Skvortsov,Koldobskii
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p. 1360 - 1369
(2007/10/03)
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- Nucleophile-induced intramolecular dipole 1,5-transfer and 1,6-cyclization: Experimental and ab initio studies of formation, thermolysis, and molecular and electronic structures of 3,6-diphenyl-1-propanesulfenimido-1,2,4,5-tetrazine
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Reaction of dichlorobenzaldazine (2) with sodium azide followed by 1-propanethiol/Et3N furnished tetrazine ylide 1 as the main product. The structure of this unprecedented ylide was confirmed with single-crystal X-ray analysis [C17H17N5S, monoclinic P21/n a = 6.8294(4) A, b = 13.6781(9) A, c = 17.5898(12) A, β = 90.666(1)°, Z = 4] and favorably compared with the results of ab initio calculations. The mechanisms of formation of the ylide and its thermal decomposition to 2,5-diphenyltetrazine (5) were investigated using ab initio methods and correlated with the experimental observations. The results suggest that formation of 1 involves intramolecular cyclization of a nitrile imine and thermolysis of 1 might generate a sulfenylnitrene. The formation of 1 is considered to be the first example of a potentially more general reaction.
- Kaszynski, Piotr,Young Jr., Victor G.
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p. 2087 - 2095
(2007/10/03)
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- BADANIA W DZIEDZINIE TIOAMIDOW I ICH POCHODNYCH IX. SYNTEZA POCHODNYCH 1,2,4,5-TETRAZYNY
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In reactions of N,N-disubstituted thioamides, derivatives of 4-thiobenzoylmorpholine, 1-thiobenzoylpiperidine and N1,N2-di(α-morpholinobenzylidene)azine, N1,N2-di(α-piperidinobenzylidene)azine also 4-(R-α-phenylaminobenzylidene)morpholinium and 1-(R-α-phenylaminobenzylidene)piperidinium iodides with hydrazine there was obtained a series compounds, derivatives of 1,2,4,5-tetrazine.Structures of obtained compounds have been determined by elemental analysis and on the ground of their UV and IR spectra.
- Santus, Maria
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p. 183 - 188
(2007/10/02)
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- Radical Cations and Anions of 1,2,4,5-Tetrazines: an Electron Spin Resonance and Cyclic Voltammetric Study
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Exposure to (60)Co γ-ray of dilute solutions of a range of s-tetrazines in fluorotrichloromethane at 77 K gave the corresponding radical cations, identified by their e.s.r. spectra.Two distinct types of spectra were obtained, one showing large hyperfine coupling to four equivalent (14)N nuclei is assigned to n(?)-radical cations, and the other, only found for -NR2 substituents, with strong coupling to two nitrogen nuclei, is assigned to ?-radical cations.The former include the parent s-tetrazine and the 3,6-dimethyl, -diphenyl, dichloro, dimethoxy, bis(methylthio), and di(aziridin-1-yl) derivatives.The latter were also prepared in fluid solution, and showed reversible behaviour in their cyclic voltammograms, in contrast with the former group.The corresponding radical anions have been studied in both fluid and solid solution, all derivatives showing major hyperfine coupling to the four ring (14)N nuclei.Total spin densities have been estimated for both types of radical cations and for the radical anions, and in all cases the total is in the 1.05-1.2 range.This deviation from unity is interpreted in terms of spin polarisation giving rise to considerable negative spin densities.
- Fischer, Hans,Mueller, Thomas,Umminger, Irmgard,Neugebauer, Franz A.,Chandra, Harish,Symons, Martyn C. R.
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p. 413 - 422
(2007/10/02)
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- Rearrangement Reactions of 1,3,6-Triaryl-1,4-dihydro-s-tetrazines leading to 2,4-Diarylquinazolines, 1-Anilino-3,5-diaryl-1H-1,2,4-triazoles, 1,3,5-Triaryl-1H-1,2,4-triazoles, and 2,5-Diaryl-1H-1,3,4-oxadiazoles. X-ray Structure Determination of 6-Isopropyl-2,4-diphenylquinazoline
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1,3,6-Triaryl-1,4-dihydro-s-tetrazines (2c-g) rearrange on heating at ca. 200 deg C to 2,4-diarylquinazolines (for which an X-ray determination was carried out on the 6-isopropyl compound) and 1-anilino-3,5-diaryl-1H-1,2,4-triazoles as major products.Hydrolysis in chloroform solution of the title compounds (2) and their 1-alkyl analogues gives rise to 1-aryl (or alkyl)-3,5-diaryl-1H-1,2,4-triazoles and 2,5-diaryl-1,3,4-oxadiazoles.
- Hunter, Daniel,Neilson, Douglas G.,Weakley, Timothy J.R.
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p. 2709 - 2712
(2007/10/02)
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- An Investigation into the Mechanism of Formation of Oxadiazoles and Arylidenehydrazides from the Action of Methanolic Potassium Hydroxide on 1,4-Dihydro-s-tetrazines.
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3,6-Diaryl- and 3,6-dibenzyl-1,4-dihydro-s-tetrazines have been shown to be inert to methanolic alkali under nitrogen.Oxadiazoles derived from these substances by the action of alkali in methanol in air result from alkali attack on the tetrazines themselves and not on the reduced derivatives as previously believed. 1,4-Dihydro-3,6-bis(α-hydroxybenzyl)-s-tetrazine is likewise stable to alkali under nitrogen but on exposure to air yields the benzylidene derivative of mandelohydrazide.Mechanisms are here proposed for the formation of the oxadiazoles and hydrazides.
- Hunter, Daniel,Neilson, Douglas G.
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p. 1081 - 1086
(2007/10/02)
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- The Role of Lithium Amides as Reducing Agents in a Novel Pathway to 3,6-Diarylpyridazines by Ring Transformations of 3,6-Diaryl-s-tetrazines
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3,6-Diaryl-s-tetrazines undergo two competing reactions when treated with lithium amides.The first, direct nucleophilic attack and addition of lithium amide to the tetrazine, appears to be predominant when a less hindered amide is used, and moderate quantities of tetrazine are then regenerated on quenching.The competing reaction, which is seen more clearly with a bulkier amide such as lithium di-isopropylamide, involves reduction of tetrazine to a dihydro derivative with concomitant formation of imine from the amide: this imine is then attacked by further amide and gives rise to a charged intermediate which reacts with more tetrazine to form a pyridazine.
- Hunter, Daniel,Neilson, Douglas G.
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p. 1601 - 1603
(2007/10/02)
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- Three Component Reactions. XIV. 2-Imidazolines and 1,2,4-Triazoles by Ring Closure Reactions of N-(2-Chloro-alkyl)imidchlorides with Hydrazine and Hydrazones
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N-(2-Chloro-alkyl)benzimidchlorides (1a and 1b) give with hydrazine in dependence on the reaction medium 1,1'-bis(2-imidazolines) (4), 1-benzamido-2-imidazolines (5) or 1,2,4-triazoles (6 and 7) and also N-(2-chloro-alkyl)benzamides (8).From imidchlorides
- Neumann, R.,Beger, J.
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p. 1026 - 1032
(2007/10/02)
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- DIELS-ALDER REACTIONS WITH INVERSE ELECTRON DEMAND. II. THE REACTION OF BENZAMIDINE WITH ?-DEFICIENT HETEROAROMATIC COMPOUNDS
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Benzamidine (I) reacts with several s-tetrazines to give as-triazines in moderate to good yield, together with some s-triazines; separate experiments have shown that these are due to the fact that (I) also undergoes Diels-Alder-reactions with as- and even with s-triazines.
- Figeys, H. P.,Mathy, A.
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p. 1393 - 1396
(2007/10/02)
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- Reactions of Relevance to the Chemistry of Aminoglycoside Antibiotics. Part 13. A Novel Synthesis of Benzyl Ethers
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Benzyl ethers were prepared from alcohols by reaction with chloro(phenylmethyl)dimethylammonium chloride and sodium hydrogen telluride in sequence.The salt (1) 1)OR2Cl-; R1=H, R2=cholest-5-en-3β-yl> and sodium borohydride gave the borane complex of 3β-dimethylaminomethoxycholest-5-ene.Salt (1; R1=Ph, R2=cholest-5-en-3β-yl or 5α-cholestan-3β-yl) and ammonia or hydrazine gave the steroidal benzimidates or benzhydrazonate.
- Barrett, Anthony G. M.,Read, Roger W.,Barton, Derek H. R.
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p. 2184 - 2190
(2007/10/02)
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- Photochemistry of Heterocycles, 8. The Photoreaction of 2,5-Diaryl-1,3,4-oxadiazoles with 1,3-Dimethyluracils. A New and Simple Synthesis of 1,2,4,5-Tetrazines
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Upon UV-irradiation 2,5-diaryl-1,3,4-oxadiazoles 2a-g do not undergo (2+2)-cycloaddition with 1,3-dimethyluracil, but instead ring cleavage occurs to afford the benzoylhydrazones 3a-e as well as the decomposition products 4-6.With 6-chloro-1,3-dimethyluracil (1b) 3h is formed, which in turn photoeliminates benzoyl chloride to give the pyrazolopyrimidine 7.Saponification of 3a gives smoothly 5-benzoyl-1,3-dimethyluracil (photoselective 5-benzoylation). - A new and simple synthesis of 3,6-disubstituted 1,2,4,5-tetrazines from aroylhydrazines is described, employing the system triphenylphosphane/hexachloroethane/triethylamine.
- Farkas, Lajos,Keuler, Josef,Wamhoff, Heinrich
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p. 2566 - 2574
(2007/10/02)
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