- Cobalt-catalysed C–H methylation for late-stage drug diversification
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The magic methyl effect is well acknowledged in medicinal chemistry, but despite its significance, accessing such analogues via derivatization at a late stage remains a pivotal challenge. In an effort to mitigate this major limitation, we here present a strategy for the cobalt-catalysed late-stage C–H methylation of structurally complex drug molecules. Enabling broad applicability, the transformation relies on a boron-based methyl source and takes advantage of inherently present functional groups to guide the C–H activation. The relative reactivity observed for distinct classes of functionalities were determined and the sensitivity of the transformation towards a panel of common functional motifs was tested under various reaction conditions. Without the need for prefunctionalization or postdeprotection, a diverse array of marketed drug molecules and natural products could be methylated in a predictable manner. Subsequent physicochemical and biological testing confirmed the magnitude with which this seemingly minor structural change can affect important drug properties. [Figure not available: see fulltext.]
- Ackermann, Lutz,Friis, Stig D.,Johansson, Magnus J.
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p. 511 - 519
(2020/06/05)
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- Manganese-catalyzed directed methylation of C(sp2)-H bonds at 25 °C with high catalytic turnover
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We report here a manganese-catalyzed C-H methylation reaction of considerable substrate scope, using MeMgBr, a catalytic amount of MnCl2· 2LiCl, and an organic dihalide oxidant. The reaction features ambient temperature, low catalyst loading, typically 1%, high catalytic turnover reaching 5.9 × 103, and no need for an extraneous ligand and illustrates a unique catalytic use of simple manganese salts for C-H activation, which so far has relied on catalysis by manganese carbonyls.
- Sato, Takenari,Yoshida, Takumi,Al Mamari, Hamad H.,Ilies, Laurean,Nakamura, Eiichi
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supporting information
p. 5458 - 5461
(2017/11/06)
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- Isochromanone-based urotensin-II receptor agonists
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A series of analogues of the selective non-peptide urotensin II (UII) receptor agonist 3-(4-chlorophenyl)-3-(2-dimethylaminoethyl)-isochroman-1-one (AC-7954, 1) was synthesized and evaluated for UII agonist activity using a functional cell-based assay. The introduction of a methyl group in the 4-position resulted in a complete loss of activity, whereas substituents in the aromatic rings were beneficial. Sterically demanding amino groups were also detrimental to the activity. Several potent agonists were identified, six compounds being equally or more potent than 1. The most potent compound in the series was the 6,7-dimethyl analogue of 1 (16, pEC50 6.87). The racemate of 16 was resolved into the pure enantiomers using preparative straight phase HPLC. It was shown that the potency resides in the (+)-enantiomer (pEC50 7.11). The synthesized compounds seem to be selective for the UII receptor as no activities were observed at the closely related SSTR3 and 5 receptors.
- Lehmann, Fredrik,Currier, Erika A.,Olsson, Roger,Hacksell, Uli,Luthman, Kristina
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p. 3057 - 3068
(2007/10/03)
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