- NOVEL IMIDAZO-PYRAZINE DERIVATIVES
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The invention provides novel imidazo-pyrazine derivatives having the general formula (I), and pharmaceutically acceptable salts thereof, wherein X, m, n, and R1to R3 are as described herein: formula (I). Further provided are pharmace
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Page/Page column 45; 87-88
(2021/12/31)
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- Palladium on Polydopamine: Its True Potential in Catalytic Transfer Hydrogenations and Heck Coupling Reactions
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The application of Pd–polydopamine and magnetic Fe3O4@Pd–polydopamine catalysts in catalytic transfer hydrogenation reactions and the Heck arylation is reported. The reduction of a wide range of aromatic nitro-compounds bearing both electron-donating and -withdrawing substituents to the corresponding anilines could be efficiently performed, although the reduction of carbonyl compounds was found to be less general. In the latter case, only aromatic ketones could be reduced to the corresponding alcohols, whereas aldehyde substrates were unaffected, which may be owing to their reaction with the catalyst support leading to catalyst deactivation. By using magnetic Fe3O4@Pd–polydopamine system, facilitated catalyst recovery and reuse for five consecutive cycles without considerable loss of activity in nitro-group reduction. The efficiency of the catalyst in Heck reactions was comparable to that in transfer hydrogenation, however, no catalytic activity was observed upon reuse in this case, likely as a result of metal leaching. We also explored tandem Heck reaction/catalytic transfer hydrogenation sequences, however, the two reactions showed limited compatibility under the applied conditions.
- Kunfi, Attila,Szabó, Vivien,Mastalir, ágnes,Bucsi, Imre,Mohai, Miklós,Németh, Péter,Bertóti, Imre,London, Gábor
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supporting information
p. 3236 - 3244
(2017/08/29)
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- Quinone Imine Route to Benzimidazol-2-ylcarbamates. Part 1. Synthesis of Open-chain and Cyclic 5-Acylamino Derivatives.
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The synthesis of the N',N''-bismethoxycarbonyl-N-(4-acylaminophenyl)guanidines (4) and (7) is described.Oxidation of these with LTA has led to the benzimidazol-2-ylcarbamates. (8), (9) and (10) through a regiospecific cyclisation of quinone imine intermediates.If the acylamino group is part of a ring, the yield of benzimidazoles (15) increases with the size of the lactam ring.The direction of ring closure may be controlled by electronic and steric factors.
- Rajappa, Srinivasachari,Sreenivasan, Ramaswami,Khalwadekar, Asha
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p. 1657 - 1675
(2007/10/02)
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- Process for preparing 4-amino-3-methyl-N-substituted or unsubstituted alkylanilines
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A process for the preparation of 4-amino-3-methyl-N-substituted or unsubstituted alkylanilines comprising acylating and/or sulfonylating 4-amino-3-methyl-nitro-benzene having the formula (I) STR1 with an acylation or sulfonylation agent to obtain a compound having the general formula (II) STR2 wherein R1 represents a hydrogen atom or an acyl group, R2 represents an acyl group or a sulfonyl group, or R1 and R2 can combine as a difunctional acyl group; reducing the nitro group of the compound having the general formula (II) with hydrogen in the presence of a metal hydrogenation catalyst to obtain a compound having the general formula (III) STR3 wherein R1 and R2 are as above defined; alkylating the amino group of the compound having the general formula (III) with an alkylation agent selected from the group consisting of an alkyl halide, a substituted alkyl halide and an alkylene oxide to obtain a compound having the general formula (IV) STR4 wherein R1 and R2 are as above defined, R3 represents an alkyl group or a substituted alkyl group and R4 represents a hydrogen atom, an alkyl group or a substituted alkyl group; and hydrolyzing the compound having the general formula (IV) to obtain a compound having the general formula (V) STR5 wherein R3 and R4 are as above defined.
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