N-tert-Butyldimethylsilyl Imines as Intermediates for the Synthesis of Amines and Ketones

Zinc chloride-catalyzed Grignard addition reaction of aromatic nitriles

In the alkyl addition reaction of aromatic nitriles using Grignard reagents, ketones are formed after hydrolysis. However, this addition reaction is often slow compared to that using reactive organolithium(i) reagents. In this study, we improved the reaction by using zinc(ii)ates, which are generated in situ using Grignard reagents and zinc chloride (ZnCl2) as a catalyst. As a result, the corresponding ketones and amines were obtained via hydrolysis and reduction, respectively, in good yields under mild reaction conditions. Scale-up reactions are also demonstrated. Interestingly, using a catalytic amount of ZnCl2 was more effective than using a stoichiometric amount of zinc(ii)ates. Possible transition states are proposed on the basis of the active zinc(ii)ate species, and DFT calculations were carried out to elucidate a plausible reaction mechanism.

Access to ortho-Hydroxyphenyl Ketimines via Imine Anion-Mediated Smiles Rearrangement

We have achieved a facile access to N-(2-halophenyl)-2-hydroxyphenylimine derivatives via imine anion-mediated Smiles rearrangement. When 2-(2-halophenoxy)benzonitriles were treated with 1.2-1.4 equiv of organolithium reagents, nucleophilic addition to the nitrile group followed by Smiles rearrangement occurred to give various N-(2-halophenyl)-2-hydroxyphenylimine derivatives, which are sometimes difficult to synthesize by the conventional acid-promoted condensation reaction between carbonyl compounds and aniline derivatives, in good to excellent chemical yields (up to 91%).

Facile Preparation of Aryl Nitriles from Aryl Aldehydes in PEG-DME 250

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A facie and efficient method for one-pot transformation of aryl aldehydes to aryl nitriles using hydroxylamine hydrochloride and phosphorus tribromide in PEG-DME 250 is reported. The conversion of various aryl aldehydes to the corresponding aryl nitriles occurred smoothly in high yields under the present reaction conditions.

Building a Chemical Toolbox for Human Pregnane X Receptor Research: Discovery of Agonists, Inverse Agonists, and Antagonists Among Analogs Based on the Unique Chemical Scaffold of SPA70

Pregnane X receptor (PXR) plays roles in detoxification and other physiological processes. PXR activation may enhance drug metabolism (leading to adverse drug reactions) or inhibit inflammation. Therefore, PXR agonists, antagonists, and inverse agonists may serve as research tools and drug candidates. However, a specific PXR modulator with an associated structure-activity relationship is lacking. Based on the scaffold of specific human PXR (hPXR) antagonist SPA70 (10), we developed 81 SPA70 analogs and evaluated their receptor-binding and cellular activities. Interestingly, analogs with subtle structural differences displayed divergent cellular activities, including agonistic, dual inverse agonistic and antagonistic, antagonistic, and partial agonistic/partial antagonistic activities (as in compounds 111, 10, 97, and 42, respectively). We generated a pharmacophore model that represents 81 SPA70 analogs, and docking models that correlate strong interactions between the compounds and residues in the AF-2 helix with agonistic activity. These compounds are novel chemical tools for studying hPXR.

A combined experimental and computational study of NHC-promoted desulfonylation of tosylated aldimines

NHC-catalyzed mild desulfonylation of tosylated aldimines provides efficient access to aryl nitriles with broad substrate scope. DFT calculations demonstrate that the reaction undergoes multiple stepwise processes.

Copper-Catalyzed Borylative Cyclization of in Situ Generated o-Allenylaryl Nitriles with Bis(pinacolato)diboron

A Cu-catalyzed cascade borylcupration/cyclization of in situ generated allene-nitriles with B₂pin₂ has been developed, which provides highly substituted 3-boryl-1-naphthylamines with excellent regioselectivity and wide functional group compatibility. It has been shown that, for the first time, the catalytically generated allylcopper species can be captured by a cyano group from a normal nitrile to furnish a carbocycle.

A practical iodine-catalyzed oxidative conversion of aldehydes to nitriles

A simple and efficient method for the direct synthesis of nitriles from aldehydes using ammonium acetate as the nitrogen source, iodine as the catalyst, and tert-butyl hydroperoxide (TBHP) as the oxidant was developed.

Synthesis of isotopically labeled daclatasvir for use in human clinical studies

Daclatasvir is a novel hepatitis C virus NS5A inhibitor developed by Bristol-Myers Squibb and marketed as Daklinza®. The need to support the development of daclatasvir required the synthesis of carbon-14 labeled material for use in human absorption, distribution, metabolism, and excretion studies. A total of 7.53 mCi of [(14) C]-daclatasvir was synthesized in eight steps from commercially available [(14) C]-copper cyanide. The radiochemical purity was 99.6%, and specific activity was 3.86 μCi/mg. To support a human absolute bioavailability study, 5.56 g of [(13) C2 , (15) N4 ]-daclatasvir was synthesized in four steps.