- Controlling Selectivity in the Synthesis of Z-α,β-Unsaturated Amidines by Tuning the N-Sulfonyl Group in a Rhodium(II) Catalyzed 1,2-H Shift
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N2-Sulfonyl-α-diazo amidines can be synthesized by the reaction of electron rich alkynyl amines with electron poor sulfonyl azides through 1,3-dipolar cycloaddition that proceeds with perfect regioselectivity. In the presence of rhodium(II) carboxylate catalysts, denitrogenation occurs to give the corresponding metallocarbene but there are then two competing processes: 1,2–H shift and O-transfer from the sulfonyl group to the metallocarbene center. The outcome can be controlled using an electron poor nitrobenzenesulfonyl group and large carboxylate rhodium ligands to select for 1,2–H shift, forming α,β-unsaturated amidines in high yield and with excellent Z-selectivity.
- Boyer, Alistair,Martin, Matthew L.
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p. 5857 - 5861
(2021/11/27)
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- PYRAZOLES USEFUL IN THE TREATMENT OF INFLAMMATION
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There is provided compounds of formula (I), wherein R1, R2, X1, X2 and n have meanings given in the description, and pharmaceutically-acceptable salts thereof, which compounds are useful in the treatment of diseases in which inhibition of the activity of a lipoxygenase (e.g. 15-lipoxygenase) is desired and/or required, and particularly in the treatment of inflammation.
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Page/Page column 53
(2008/06/13)
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- Preparation with heterogeneous catalysis of N-alkyl-substituted aminoalkynes
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A process for preparing N-alkyl-substituted aminoalkynes by reacting an alkyne with a carbonyl compound and an amine with heterogeneous catalysis in which an unsupported copper acetylide derived from malachite is used as the catalyst. The N-alkyl-substituted aminoalkyne have a wide variety of uses including their use as precursors for pharmaceuticals, their use in electroplating processes and their use as corrosion inhibitors.
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- Base-catalysed isomerization of 2-propynylamines. Synthesis of (dialkylamino)allenes
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A number of (dialkylamino)allenes 2 have been obtained in excellent yields and in a reasonable state of purity by isomerization of dialkyl-2-propynylamines 1 with potassium tert-butoxide in tetrahydrofuran or with the complex t-BuOK*t-BuOH in hexamethylphosphoric triamide.Treatment of the 2-propynylamines with t-BuOK in dimethyl sulfoxide leads to equilibrium mixtures of the allenic amines 2 and dialkyl-1-alkynylamines 3.
- Verkruijsse, H. D.,Bos, H. J. T.,Noten, L. J. de,Brandsma, L.
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p. 244 - 246
(2007/10/02)
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