Metal-Free Twofold Electrochemical C−H Amination of Activated Arenes: Application to Medicinally Relevant Precursor Synthesis

The efficient production of many medicinally or synthetically important starting materials suffers from wasteful or toxic precursors for the synthesis. In particular, the aromatic non-protected primary amine function represents a versatile synthetic precursor, but its synthesis typically requires toxic oxidizing agents and transition metal catalysts. The twofold electrochemical amination of activated benzene derivatives via Zincke intermediates provides an alternative sustainable strategy for the formation of new C−N bonds of high synthetic value. As a proof of concept, we use our approach to generate a benzoxazinone scaffold that gained attention as a starting structure against castrate-resistant prostate cancer. Further improvement of the structure led to significantly increased cancer cell line toxicity. Thus, exploiting environmentally benign electrooxidation, we present a new versatile and powerful method based on direct C−H activation that is applicable for example the production of medicinally relevant compounds.     

Synthesis of Bis(phosphanyl)alkane Monosulfides by the Addition of Diphosphane Monosulfides to Alkenes under Light

Bis-phosphanated compounds are regarded as the most ubiquitous privileged ligand structures in transition-metal catalysis. The development of highly atom economical reactions is of great importance for their syntheses because less atom economical methods often require complicated purification procedures under inert atmospheres to remove excess starting materials and byproducts. Herein, the photoinduced addition reactions of diphosphane monosulfides bearing P^V(S)−P^III single bonds to alkenes is disclosed. These reactions require only equimolar amounts of the diphosphane monosulfide relative to the alkene and facilitate highly selective introduction of two different types of phosphorus-containing groups, such as thiophosphoryl and phosphanyl groups, into a variety of alkenes without any catalyst, base, or additive.     

Decacyclene Radical Anions Showing Strong Low‐energy Intramolecular Absorption and Magnetic Coupling of Spins in a Hexagonal Network

Two salts of the aromatic hydrocarbon decacyclene, {cryptand[2.2.2](Cs⁺)} (decacyclene^.?) ( 1 ) and {Bu₃MeP⁺}(decacyclene^.?) ( 2 ), were obtained. In both salts, decacyclene^.? radical anions formed channels occupied by cations. However, corrugated hexagonal decacyclene^.? layers could be outlined in the crystal structure of 1 with several side‐by‐side C???C approaches. The decacyclene^.? radical anions showed strong distortion in both salts, deviating from the C₃ symmetry owing to the repulsion of closely arranged hydrogen atoms and the Jahn‐Teller effect. Radical anions showed intense unusually low energy absorption in the IR‐range, with maxima at 4800 and 6000 cm^?1. According to the carculations, these bands can originate from the SOMO‐LUMO+1 and SOMO‐LUMO+2 transitions, respectively. Radical anions exhibited a S=1/2 spin state, with an effective magnetic moment of 1.72 μ_B at 300 K. The decacyclene^.? spin antiferromagnetically coupled with a Weiss temperature of ?11 K. Spin ordering was not observed down to 1.9 K owing to spin frustration in the hexagonal decacyclene^.? layers.     

Synthesis of well‐defined,soluble poly(3‐alkyl‐4‐benzamide) by chain‐growth condensation polymerization

Well‐defined poly(3‐alkyl‐4‐benzamide) was synthesized by means of chain‐growth condensation polymerization of phenyl 3‐octyl‐4‐(4‐octyloxybenzyl(OOB)amino)benzoate ( 1c ) from initiator 2 , followed by removal of the OOB groups on amide nitrogen of poly 1c . Polymerization of 1c with phenyl 4‐(trifluoromethyl)benzoate ( 2b ) in the presence of 1,1,1,3,3,3‐hexamethyldisilazide (LiHMDS) and LiCl in THF at ?10 °C gave poly 1c with a narrow molecular weight distribution (M_w/M_n ≤ 1.08) and a well‐defined molecular weight (M_n = 4480–12,700) determined by the feed ratio of monomer to initiator (from 10 to 30). The OOB groups of poly 1c were removed with H₂SO₄ to give the corresponding N‐unsubstituted poly(p‐benzamide) (poly 1c′ ) with low polydispersity. The solublity of poly 1c′ in polar organic solvents was dramatically higher than that of poly(p‐benzamide), demonstrating that introduction of an alkyl group on the aromatic ring is very effective for improving the solubility of poly(p‐benzamide). © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 360–365     

Effect of Acid Treatment of Montmorillonite on “Support‐Activator” Performance to Support Metallocene for Propylene Polymerization Catalyst

This work is focused on montmorillonite (MMT)‐based “support‐activators” (S‐As) for the metallocene‐catalyzed propylene polymerization. This catalyst was previously industrialized; however, for further technological advances, the activation mechanism is investigated. The chemical and morphological requirements of the S‐A are surveyed using both commercially available raw clay minerals (non‐acid‐treated) and acid‐treated clay minerals. The S‐A possessing strong‐acid sites (pK a < ?8.2) gives a highly active catalyst. Acid treatment of MMT induces morphological changes as well as the formation of strong acid sites. Based on pore size distribution analysis and atomic force microscopy observations, it is concluded that the strong acid sites are located in the small pores around the edge of the clay mineral (not in the interlayer), where the structure is disordered by the acid treatment.

     

How to make a linear network code (strongly) secure

A linear network code is called k-secure if it is secure even if an adversary eavesdrops at most k edges. In this paper, we show an efficient deterministic construction algorithm of a linear transformation T that transforms an (insecure) linear network code to a k-secure one for any k, and extend this algorithm to strong k-security for any k . Our algorithms run in polynomial time if k is a constant, and these time complexities are explicitly presented. We also present a concrete size of \(|\mathsf{F}|\) for strong k-security, where \(\mathsf{F}\) is the underling finite field.     

Some functional inequalities on non-reversible Finsler manifolds

We continue our study of geometric analysis on (possibly non-reversible) Finsler manifolds, based on the Bochner inequality established by Ohta and Sturm. Following the approach of the \(\Gamma \)-calculus of Bakry et al (2014), we show the dimensional versions of the Poincaré–Lichnerowicz inequality, the logarithmic Sobolev inequality, and the Sobolev inequality. In the reversible case, these inequalities were obtained by Cavalletti and Mondino (2015) in the framework of curvature-dimension condition by means of the localization method. We show that the same (sharp) estimates hold also for non-reversible metrics.     

Caesaljaponins A and B: New Cassane‐Type Furanoditerpenoids from the Seeds of Caesalpinia decapetala var. japonica

Two new cassane‐type furanoditerpenoids, designated caesaljaponin A and caesaljaponin B ( 1 and 2 , resp.), were isolated from seeds of Caesalpinia decapetala var. japonica. The structures were elucidated by spectroscopic data, and the absolute configuration of 1 was determined by X‐ray crystallographic analysis using the anomalous scattering of CuK_α radiation.