- Discriminating non-ylidic carbon-sulfur bond cleavages of sulfonium ylides for alkylation and arylation reactions
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A sulfonium ylide participated alkylation and arylation under transition-metal free conditions is described. The disparate reaction pattern allowed the separate activation of non-ylidic S-alkyl and S-aryl bond. Under acidic conditions, sulfonium ylides serve as alkyl cation precursors which facilitate the alkylations. While under alkaline conditions, cleavage of non-ylidic S-aryl bond produces O-arylated compounds efficiently. The robustness of the protocols were established by the excellent compatibility of wide variety of substrates including carbohydrates.
- Fang, Jing,Li, Ting,Ma, Xiang,Sun, Jiuchang,Cai, Lei,Chen, Qi,Liao, Zhiwen,Meng, Lingkui,Zeng, Jing,Wan, Qian
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supporting information
p. 288 - 292
(2021/07/25)
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- Electrochemical Deprotection of para-Methoxybenzyl Ethers in a Flow Electrolysis Cell
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Electrochemical deprotection of p-methoxybenzyl (PMB) ethers was performed in an undivided electrochemical flow reactor in MeOH solution, leading to the unmasked alcohol and p-methoxybenzaldehyde dimethyl acetal as a byproduct. The electrochemical method removes the need for chemical oxidants, and added electrolyte (BF4NEt4) can be recovered and reused. The method was applied to 17 substrates with high conversions in a single pass, yields up to 92%, and up to 7.5 g h-1 productivity. The PMB protecting group was also selectively removed in the presence of some other common alcohol protecting groups.
- Green, Robert A.,Jolley, Katherine E.,Al-Hadedi, Azzam A. M.,Pletcher, Derek,Harrowven, David C.,De Frutos, Oscar,Mateos, Carlos,Klauber, David J.,Rincón, Juan A.,Brown, Richard C. D.
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p. 2050 - 2053
(2017/04/27)
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- Contra-thermodynamic Hydrogen Atom Abstraction in the Selective C-H Functionalization of Trialkylamine N-CH3 Groups
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We report a simple one-pot protocol that affords functionalization of N-CH3 groups in N-methyl-N,N-dialkylamines with high selectivity over N-CH2R or N-CHR2 groups. The radical cation DABCO+?, prepared in situ by oxidation of DABCO with a triarylaminium salt, effects highly selective and contra-thermodynamic C-H abstraction from N-CH3 groups. The intermediates that result react in situ with organometallic nucleophiles in a single pot, affording novel and highly selective homologation of N-CH3 groups. Chemoselectivity, scalability, and recyclability of reagents are demonstrated, and a mechanistic proposal is corroborated by computational and experimental results. The utility of the transformation is demonstrated in the late-stage site-selective functionalization of natural products and pharmaceuticals, allowing rapid derivatization for investigation of structure-activity relationships.
- Barham, Joshua P.,John, Matthew P.,Murphy, John A.
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p. 15482 - 15487
(2016/12/09)
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- Identification of a potent, state-dependent inhibitor of Nav1.7 with oral efficacy in the formalin model of persistent pain
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Clinical human genetic studies have recently identified the tetrodotoxin (TTX) sensitive neuronal voltage gated sodium channel Nav1.7 (SCN9A) as a critical mediator of pain sensitization. Herein, we report structure-activity relationships for a novel series of 2,4-diaminotriazines that inhibit hNav1.7. Optimization efforts culminated in compound 52, which demonstrated pharmacokinetic properties appropriate for in vivo testing in rats. The binding site of compound 52 on Nav1.7 was determined to be distinct from that of local anesthetics. Compound 52 inhibited tetrodotoxin-sensitive sodium channels recorded from rat sensory neurons and exhibited modest selectivity against the hERG potassium channel and against cloned and native tetrodotoxin-resistant sodium channels. Upon oral administration to rats, compound 52 produced dose- and exposure-dependent efficacy in the formalin model of pain.
- Bregman, Howard,Berry, Loren,Buchanan, John L.,Chen, April,Du, Bingfan,Feric, Elma,Hierl, Markus,Huang, Liyue,Immke, David,Janosky, Brett,Johnson, Danielle,Li, Xingwen,Ligutti, Joseph,Liu, Dong,Malmberg, Annika,Matson, David,McDermott, Jeff,Miu, Peter,Nguyen, Hanh Nho,Patel, Vinod F.,Waldon, Daniel,Wilenkin, Ben,Zheng, Xiao Mei,Zou, Anruo,McDonough, Stefan I.,Dimauro, Erin F.
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experimental part
p. 4427 - 4445
(2011/09/14)
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