Applications of Ionic Hydrogenation to Organic Synthesis

Kursanov, D. N.; Парнес, З. Н.; Loim, N. M.

doi:10.1055/s-1974-23387

Cited by 376 publications

(161 citation statements)

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“…Reaction of the aldehyde with an excess of the appropriate Grignard reagent afforded a benzyl alcohol that underwent "ionic hydrogenation" by stirring with triethylsilane in the presence of trifluoroacetic acid (27). Deprotection of the methyl ether afforded 5-alkyl derivatives.…”

Section: Synthesis Of 5-substituted Triclosan Analogs-the Compounds Dmentioning

confidence: 99%

X-ray Structural Analysis of Plasmodium falciparum Enoyl Acyl Carrier Protein Reductase as a Pathway toward the Optimization of Triclosan Antimalarial Efficacy

Freundlich

Wang

Tsai

et al. 2007

Journal of Biological Chemistry

115

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The x-ray crystal structures of five triclosan analogs, in addition to that of the isoniazid-NAD adduct, are described in relation to their integral role in the design of potent inhibitors of the malarial enzyme Plasmodium falciparum enoyl acyl carrier protein reductase (PfENR). Many of the novel 5-substituted analogs exhibit low micromolar potency against in vitro cultures of drug-resistant and drug-sensitive strains of the P. falciparum parasite and inhibit purified PfENR enzyme with IC 50 values of <200 nM. This study has significantly expanded the knowledge base with regard to the structure-activity relationship of triclosan while affording gains against cultured parasites and purified PfENR enzyme. In contrast to a recent report in the literature, these results demonstrate the ability to improve the in vitro potency of triclosan significantly by replacing the suboptimal 5-chloro group with larger hydrophobic moieties. The biological and x-ray crystallographic data thus demonstrate the flexibility of the active site and point to future rounds of optimization to improve compound potency against purified enzyme and intracellular Plasmodium parasites.

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Section: Synthesis Of 5-substituted Triclosan Analogs-the Compounds Dmentioning

confidence: 99%

X-ray Structural Analysis of Plasmodium falciparum Enoyl Acyl Carrier Protein Reductase as a Pathway toward the Optimization of Triclosan Antimalarial Efficacy

Freundlich

Wang

Tsai

et al. 2007

Journal of Biological Chemistry

115

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“…The rate Reduction of 17 with Et 3 SiH in CF 3 CO 2 H furnished the expected mixture of two conformers of 11 in 76% yield. [27] constants were 0.36, 1.17, 2.54, and 5.44 ϫ10 Ϫ5 s Ϫ1 for from 18a to 18b, and 0.51, 1.65, 3.46, and 7.14 ϫ10 Ϫ5 s…”

mentioning

confidence: 98%

Synthesis of Pentathiepanes and Isolation of the Conformers Based on High Inversion Barrier of the Pentathiepane Ring

Sugihara

Takeda

Nakayama

1999

European J Organic Chem

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Acenaphtho[1,2‐a]acenaphthylene (1) was sulfurated with elemental sulfur to give a pentathiepane derivative (2). A dynamic NMR spectrum analysis revealed that the two naphthalene rings of 2 are chemically nonequivalent up to 100 °C. The pentathiepane ring of 2 was shown to adopt a chair conformation both in solution and crystals. In accordance with the NMR spectrum analysis, the sulfuration of 5‐phenylacenaphtho[1,2‐a]acenaphthylene (12) gave a pair of conformers (16a and 16b), which were isolated in pure form. The Friedel–Crafts acetylation of 2, followed by dithioacetalization with 1,2‐ethanedithiol, also gave a pair of isolable conformers (18a and 18b). These two pairs of conformers isomerized, as a result of the ring inversion, to each other in solution at room temperature in the first‐order kinetics. The activation parameters for this process, Ea, ΔH#, and ΔS#, were determined. Based on the experimental observations, a probable mechanism for the inversion process is proposed.

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“…This allowed us to assume that the addition of Grignard reagent to another carbonyl would occur from the convex face as well, and 1ead to 2a. N,O-acetal 2a was then subjected to ionic hydrogenation conditions 3 (Et 3 SiH, BF 3 ⋅OEt 2 , CH 2 Cl 2 ,-78°C∼rt) to give 4a as the single diastereomer. Similar treatment of 3a provided diastereoselectively 5a as the only isomer.…”

Section: Introductionmentioning

confidence: 99%

Further studies on the reductive–alkylation of chiral endo-himimide derived from (R)-phenylglycinol

Ye¹,

Huang

et al. 2004

Arkivoc

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The scope of the reductive-alkylation of chiral endo-himimide derived from (R)-phenylglycinol was studied. Careful structural studies by means of both X-ray crystallographical analysis and 1 H NMR spectroscopy analysis on the intermediates and products obtained during these studies allowed us to assign the structures of all the products obtained, and then to conclude that both the Grignard reagents addition (to 1) and the reductive deoxygenation of 2/3 via N-acyliminium intermediates A occurred stereospecifically from the convex face of either 1 or A.

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Applications of Ionic Hydrogenation to Organic Synthesis

Cited by 376 publications

References 0 publications

X-ray Structural Analysis of Plasmodium falciparum Enoyl Acyl Carrier Protein Reductase as a Pathway toward the Optimization of Triclosan Antimalarial Efficacy

X-ray Structural Analysis of Plasmodium falciparum Enoyl Acyl Carrier Protein Reductase as a Pathway toward the Optimization of Triclosan Antimalarial Efficacy

Synthesis of Pentathiepanes and Isolation of the Conformers Based on High Inversion Barrier of the Pentathiepane Ring

Further studies on the reductive–alkylation of chiral endo-himimide derived from (R)-phenylglycinol

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