A deconstruction-reconstruction strategy to access 1-naphthol derivatives: application to the synthesis of aristolactam scaffolds.

A deconstruction-reconstruction strategy for the synthesis of multisubstituted polycyclic aromatic hydrocarbons (PAHs) is delineated herein. The deconstruction step enables the synthesis of -cyanomethylaroyl fluorides that are bifunctional substrates holding both a pro-nucleophile and an electrophile. The construction step involves a formal [4 + 2] benzannulation using -cyanomethylaroyl fluorides and active methylenes.

Reversed-Polarity Synthesis of -Sulfonyl Ketimines with Imidoylsilanes and Diaryliodonium Salts via Palladium-Catalyzed Reactions.

Imines are important building blocks in organic chemistry. Iminines, aldimines and ketimines, have been traditionally synthesized by the condensation reaction of the corresponding carbonyl compound with an amine moiety. More recently, palladium-catalyzed synthesis of ketimines using imidoyl chlorides has been reported.

Corrosion Inhibition of Mild Steel and 304 Stainless Steel in 1 M Hydrochloric Acid Solution by Tea Tree Extract and Its Main Constituents.

Tea tree extract, containing antioxidant constituents α-terpineol, terpinen-4-ol, and α-terpinene, has a wide range of applications in the cosmetic, food, and pharmaceutical industries. In this study, tea tree extract showed an anticorrosive effect under 1 M HCl solution on mild steel (MS) and 304 stainless steel (STS). Uniform corrosion for MS and pitting corrosion for STS at 298 K were retarded, with inhibition efficiencies of 77% and 86%, respectively.

Recent Advances in One-Pot Modular Synthesis of 2-Quinolones.

It is known that 2-quinolones are broadly applicable chemical structures in medicinal and agrochemical research as well as various functional materials. A number of current publications about their synthesis and their applications emphasize the importance of these small molecules. The early synthetic chemistry originated from the same principle of the classical Friedländer and Knorr procedures for the preparation of quinolines.

Development and structure-activity relationship study of SHP2 inhibitor containing 3,4,6-trihydroxy-5-oxo-5H-benzo[7]annulene.

SHP2, a non-receptor protein tyrosine phosphatase encoded by PTPN11 gene, plays an important role in the cell growth and proliferation. Activating mutations of SHP2 have been reported as a cause of various human diseases such as solid tumors, leukemia, and Noonan syndrome. The discovery of SHP2 inhibitor can be a potent candidate for the treatment of cancers and SHP2 related human diseases.

Chan-Lam coupling reaction of sulfamoyl azides with arylboronic acids for synthesis of unsymmetrical -arylsulfamides.

An efficient method was developed for the synthesis of unsymmetrical -arylsulfamides using sulfamoyl azides and arylboronic acids in the presence of 10 mol% of copper chloride as the catalyst. The reaction was facilitated in MeOH in an open flask at room temperature. Unlike the coupling of sulfamides and boronic acids, the use of sulfamoyl azides was found to be beneficial with respect to the yield and reaction time.

3-Hydroxy-2-(trialkylsilyl)phenyl Triflate: A Benzyne Precursor Triggered via 1,3-C-sp-to-O Silyl Migration.

3-Hydroxy-2-(trialkylsilyl)phenyl triflates are presented as new versatile hydroxyaryne precursors. These are base-activated aryne precursors induced via a C-sp-to-O 1,3-Brook rearrangement. The reaction of various arynophiles and 3-trialkylsiloxybenzyne generated from 3-hydroxy-2-(trialkylsilyl)phenyl triflate efficiently afforded highly regioselective phenol derivatives.

Total Synthesis of Swinholide A: An Exposition in Hydrogen-Mediated C-C Bond Formation.

Diverse hydrogen-mediated C-C couplings enable construction of the actin-binding marine polyketide swinholide A in only 15 steps (longest linear sequence), roughly half the steps required in two prior total syntheses. The redox-economy, chemo- and stereoselectivity embodied by this new class of C-C couplings are shown to evoke a step-change in efficiency.

Formal Synthesis of Premisakinolide A and C(19)-C(32) of Swinholide A via Site-Selective C-H Allylation and Crotylation of Unprotected Diols.

Using stereo- and site-selective C-H allylation and crotylation of unprotected diols, an intermediate in the synthesis of premisakinolide A (bistheonellic acid B) that was previously made in 16-27 (LLS) steps is now prepared in only nine steps. This fragment also represents a synthesis of C(19)-C(32) of the actin-binding macrodiolide swinholide A.

Reductive Cyclization of Halo-Ketones to Form 3-Hydroxy-2-Oxindoles Palladium Catalyzed Hydrogenation: A Hydrogen-Mediated Grignard Addition.

The reductive cyclization of -oxoacyl -bromoanilides to form 3-hydroxy-2-oxindoles under the conditions of palladium catalyzed hydrogenation is described. This work may be viewed as a prelude to intermolecular hydrogen-mediated Grignard-type reductive couplings of organic halides with carbonyl compounds.

Asymmetric Iridium-Catalyzed C-C Coupling of Chiral Diols via Site-Selective Redox-Triggered Carbonyl Addition.

Cyclometalated π-allyliridium C,O-benzoate complexes modified by axially chiral chelating phosphine ligands display a pronounced kinetic preference for primary alcohol dehydrogenation, enabling highly site-selective redox-triggered carbonyl additions of chiral primary-secondary 1,3-diols with exceptional levels of catalyst-directed diastereoselectivity. Unlike conventional methods for carbonyl allylation, the present redox-triggered alcohol C-H functionalizations bypass the use of protecting groups, premetalated reagents, and discrete alcohol-to-aldehyde redox reactions.

Catalyst-directed diastereo- and site-selectivity in successive nucleophilic and electrophilic allylations of chiral 1,3-diols: protecting-group-free synthesis of substituted pyrans.

The iridium-catalyzed, protecting group-free synthesis of 4-hydroxy-2,6-cis- or trans-pyrans through successive nucleophilic and electrophilic allylations of chiral 1,3-diols occurs with complete levels of catalyst-directed diastereoselectivity in the absence of protecting groups, premetallated reagents, or discrete alcohol-to-aldehyde redox reactions.

Catalytic enantioselective C-H functionalization of alcohols by redox-triggered carbonyl addition: borrowing hydrogen, returning carbon.

The use of alcohols and unsaturated reactants for the redox-triggered generation of nucleophile-electrophile pairs represents a broad, new approach to carbonyl addition chemistry. Discrete redox manipulations that are often required for the generation of carbonyl electrophiles and premetalated carbon-centered nucleophiles are thus avoided. Based on this concept, a broad, new family of enantioselective C-C coupling reactions that are catalyzed by iridium or ruthenium complexes have been developed, which are summarized in this Minireview.

Pd-catalyzed Suzuki-Miyaura cross-coupling reactions between sulfamates and potassium Boc-protected aminomethyltrifluoroborates.

Sulfamates were studied as the electrophilic partners in the palladium-catalyzed Suzuki-Miyaura cross-coupling reaction with potassium Boc-protected primary and secondary aminomethyltrifluoroborates. A broad range of substrates was successfully coupled to provide the desired products. Complex molecules containing a new carbon-carbon bond and an aminomethyl moiety could be prepared through this developed method.

Potassium Boc-protected secondary aminomethyltrifluoroborates: synthesis and Suzuki-Miyaura cross-coupling reactions.

Seven potassium Boc-protected secondary aminomethyltrifluoroborates were prepared in a standardized two-step process. The Suzuki-Miyaura cross-coupling reaction was studied with this new class of nucleophiles, and a large variety of aryl and hetaryl chlorides provided the desired products in good to excellent yields, thereby allowing easy access to secondary aminomethyl substructures.

Suzuki-Miyaura cross-coupling reactions of potassium Boc-protected aminomethyltrifluoroborate with aryl and hetaryl mesylates.

Palladium-catalyzed Suzuki-Miyaura cross-coupling reactions were studied with potassium Boc-protected aminomethyltrifluoroborate through C-O activation of various mesylate derivatives to afford the corresponding products in moderate to good yields.

Synthesis and Suzuki-Miyaura cross-coupling reactions of potassium Boc-protected aminomethyltrifluoroborate with aryl and hetaryl halides.

Potassium Boc-protected aminomethyltrifluoroborate, a primary aminomethyl equivalent, was synthesized successfully through a "one-pot" process. With this trifluoroborate, Suzuki-Miyaura cross-coupling reactions were investigated with a variety of both aryl and hetaryl chlorides in good to excellent yields.

Palladium-catalyzed Suzuki-Miyaura cross-coupling reactions of enantiomerically enriched potassium β-trifluoroboratoamides with various aryl- and hetaryl chlorides.

Enantiomerically enriched potassium β-trifluoroboratoamides were synthesized as air-stable solids in greater than 95:5 dr using pseudoephedrine as the chiral auxiliary. With these chiral nucleophiles, Suzuki-Miyaura cross-coupling reactions were carried out with various aryl- and hetaryl chlorides in good to excellent yields. Moreover, the diastereoselectivities were preserved throughout the Suzuki-Miyaura cross-coupling reactions.

YlaC is an extracytoplasmic function (ECF) sigma factor contributing to hydrogen peroxide resistance in Bacillus subtilis.

In this study, we have attempted to characterize the functions of YlaC and YlaD encoded by ylaC and ylaD genes in Bacillus subtilis. The GUS reporter gene, driven by the yla operon promoter, was expressed primarily during the late exponential and early stationary phase, and its expression increased as the result of hydrogen peroxide treatment. Northern and Western blot analyses revealed that the level of ylaC transcripts and YlaC increased as the result of challenge with hydrogen peroxide.