- Formation of tricyclic heterocycles from the condensation reaction of 1,2-diamines with 1,2-diketones
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Condensation of 1,2-diamines with 1,2-diketones yielded unexpected tricyclic heterocycles. The structures were determined by single-crystal X- ray analysis.
- Yamaguchi, Tadatoshi,Eto, Masashi,Watanabe, Kenji,Kashige, Nobuhiro,Harano, Kazunobu
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- Dihydropyrazine derivatives as a new type of DNA strand breaking agent
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The DNA strand-breaking activity of some dihydropyrazine derivatives, 2,3-dihydro-5,6-dimethylpyrazine (3), 2,3-dihydro-2,5,6-trimethylpyrazine (4), 2,3-dihydro-2,2,5,6-tetramethylpyrazine (5), trans-2,3-dimethyl- 5,6,7,8,9,10-hexahydroquinoxaline (6), its cis-compound (7) and the mixture of 6 and 7 (8) was tested by agarose gel electrophoresis using plasmid pBR322 ccc-DNA as a substrate. The order of DNA strand-breaking activity in the presence of Cu2+ was (7)>(8)≤(5)>(2)>(6)>(4)≤(1)≤(3). 2,5-Bis(D-arabino- tetrahydroxybutyl)-2,5-dihydropyrazine (1) and 2,5-dihydro-3,6- dimethylpyrazine (2) have already been described in terms of DNA breaking activity in a previous paper. The activity was suggested to be due to the dihydropyrazine skeleton, in addition to active oxygen radicals formed in an aqueous solution. The introduction of a methyl group to the dihydropyrazine skeleton enhanced the activities of dihydropyrazine derivatives. The possible chemical basis for DNA strand breakage by dihydropyrazine derivatives, especially in the presence of Cu2+, was discussed.
- Yamaguchi, Tadatoshi,Kashige, Nobuhiro,Mishiro, Noriko,Miake, Fumio,Watanabe, Kenji
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- New compounds derived from dihydropyrazines having DNA strand-breakage activity
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Dihydropyrazine derivatives such as 2,3-dihydro-5,6-dimethylpyrazine (1), 2,3-dihydro-2,5,6-trimethylpyrazine (2) and 2,3-dihydro-2,2,5,6- teramethylpyrazine (3) were found to be transformed into (2R*, 3S*, 5R*)- 1,2 ethylene-imino-1,7,10-triaza-2,3,6-trimethyl-3-hydroxy-spiro [4,5] decan- 6-ene (4), the stereoisomeric mixtures of 2,4aR*,7,9aS* - tetramethylcyclohexano [1,2-e: 4,5-e']-dipiperazin-6-ene (5) and (4aR*, 9aS*)-2,2,4a,7,7,9a-hexamethylcyclohexano [1,2-e: 4,5-e']-dipiperazin-6-ene (6), respectively. These dimerized compounds (4, 5 and 6), whose structures were determined by X-ray and nmr spectral analyses, showed almost the same DNA strand-breakage activity as their parent dihydropyrazines. The dimerization pathway is discussed on the basis of the PM3 calculation data.
- Yamaguchi, Tadatoshi,Eto, Masashi,Harano, Kazunobu,Kashige, Nobuhiro,Watanabe, Kenji,Ito, Shigeru
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- MONOACYLGLYCEROL LIPASE INHIBITORS
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Provided are compounds of formula (I), or a pharmaceutically acceptable salt or solvate thereof: Also provided are compositions comprising compounds of formula (I). The compounds and compositions are also provided for use as medicaments, for example as medicaments useful in the treatment of a condition modulated by monoacylglycerol lipase (MAGL). Also provided are the use of compounds and compositions for the inhibition of monoacylglycerol lipase (MAGL).
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Paragraph 0340-0341
(2021/09/09)
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- A reusable zirconium(IV) Schiff base complex catalyzes highly efficient synthesis of quinoxalines under mild conditions
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A zirconium(IV) complex of a bidentate Schiff base (ZrL2Cl 2) has been synthesized by the reaction of (z)-N-benzylidene-2- hydroxypropane-1-amine (HL) and ZrCl4. Spectroscopic data and elemental analyses are consistent with a monomeric complex with a ligand:Zr ratio of 2:1. The catalytic activity of ZrL2Cl2 has been investigated for the efficient synthesis of a wide variety of quinoxaline derivatives under mild conditions. The employment of ethanol as an environmentally benign solvent in this high yield method, along with high turnover numbers and reusability of the catalyst providing ready scalability, makes it appropriate for practical applications.
- Jafarpour, Maasoumeh,Rezaeifard, Abdolreza,Haddad, Reza,Gazkar, Somayeh
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- A green synthesis of quinoxalines and 2,3-dihydropyrazines
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Quinoxaline and dihydropyrazine derivatives were obtained in high yields by simple addition of 1,2-diamines and 1,2-dicarbonyl compounds in water. In some cases, the products spontaneously precipitated from the reaction mixture, making it possible to recover and reuse the mother liquor for further condensations. The very mild reaction conditions, the high yields of the products, and the absence of any catalyst make this methodology an efficient and green route to quinoxalines and dihydropyrazines. Georg Thieme Verlag Stuttgart New York.
- Delpivo, Camilla,Micheletti, Gabriele,Boga, Carla
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p. 1546 - 1552
(2013/06/27)
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- Phenyl-substituted dihydropyrazines with DNA strand-breakage activity
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Monophenyl-substituted dihydropyrazines (Ph-DHP-1 to 4) of 2,3-dihydro-5,6-dimethylpyrazine (Me-DHP-1), which have the inductive effects of apoptosis and mutagenesis, were synthesized and their biological effect was investigated in terms of DNA strand-breakage. Differences between the phenyl- and methyl-substituted dihydropyrazines were examined.
- Ito, Shigeru,Takechi, Shinji,Nakahara, Kazuhide,Kashige, Nobuhiro,Yamaguchi, Tadatoshi
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scheme or table
p. 825 - 828
(2010/09/07)
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- Solvent effect on the sensitized photooxygenation of cyclic and acyclic α-diimines
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The reaction of singlet molecular oxygen with a series of cyclic and acyclic α-diimines was studied. Time-resolved methods were used to measure total reaction rate constants and steady-state methods were used to determine chemical reaction rate constants. GC-MS was used to tentatively assign the reaction products. 5,6-Disubstituted cyclic α-diimines are singlet oxygen quenchers, but become more effective in polar solvents. A reaction mechanism involving a perepoxide intermediate or transition state leading to a hydroperoxide seems to be a key reaction path for product formation. A replacement of the phenyl substituent for a methyl substituent opens up an additional reaction involving a perepoxide-like exciplex, which increases singlet oxygen quenching of the cyclic α-diimines. The reactivity of 5,6-disubstituted cyclic α-diimines towards singlet oxygen is highly dependent on steric interactions arising from vicinal phenyl rings and from electronic effects. 1,4-Disubstituted acyclic α-diimines are, by comparison, moderate or poor singlet oxygen quenchers. Total rate constants are scarcely dependent on solvent properties, but instead correlate with the Hildebrand parameter. These results are explained in terms of a mechanism involving a dioxetane-like exciplex that gives rise to a charged intermediate leading to products.
- Lemp, Else,Zanocco, Antonio L.,Günther, German,Pizarro, Nancy
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p. 10734 - 10746
(2007/10/03)
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- PIPERAZINE UREA DERIVATIVES FOR THE TREATMENT OF ENDOMETRIOSIS
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Use of a compound of the following formula (Ia) for the production of a medicament for the treatment of endometriosis in human wherein the treatment comprises administering to a human female in need of such treatment a therapeutically effective amount of said compound.
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Page/Page column 91
(2008/06/13)
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- Piperazine derivatives and their use as anti-inflammatory agents
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This invention is directed to acyl piperazine derivatives which are useful as anti-inflammatory agents. This invention is also directed to pharmaceutical compositions containing the compounds of the invention, and methods of using the compounds to treat inflammatory disorders in humans.
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- PIPERAZINE DERIVATIVES AND THEIR USE AS ANTI-INFLAMMATORY AGENTS
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This invention is directed to acyl piperazine derivatives of formula (Ia): wherein R 1a, R 2, R 3, R 4, R 5and R 6 are defined herein, which are useful as anti-inflammatory agents. This invention is also directed to other acyl piperazine derivatives, pharmaceutical compositions containing the compounds of the invention, and methods of using the compounds to treat inflammatory disorders in humans.
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- A diamine-exchange reaction of dihydropyrazines
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Dihydropyrazines reacted with 1,2-diamines to form tetraazadecalins as intermediates, and then the reaction proceeded forward to dissociate into alternate dihydropyrazine and diamine, or backward to dissociate into the starting materials in certain equilibrium. The product distribution is controlled by diamine-exchange equilibrium reaction. The various equilibrium reactions were analyzed by NMR spectroscopy.
- Yamaguchi, Tadatoshi,Ito, Shigeru,Iwase, Yukiko,Watanabe, Kenji,Harano, Kazunobu
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p. 1677 - 1680
(2007/10/03)
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