Highly Regio-Selective Synthesis of β-Amino Alcohol by Reaction with Aniline and Propylene Carbonate in Self Solvent System over Large Pore Zeolite Catalyst

The nucleophilic ring opening of epoxides with amines is a well known route for the synthesis of β-amino alcohols. The use of carbonates offers significant advantages over epoxides as they are far less hazardous materials, safe for handling, do not require high-pressure equipment and most notably the possibility of solvent less reactions. In this work, utilization of zeolite as host catalyst in the reaction media for synthesis of β-amino alcohols without using solvent is reported.

Towards in vivo amplification: Overcoming hurdles in the use of hematopoietic stem cells in transplantation and gene therapy

With the advent of safer and more efficient gene transfer methods, gene therapy has become a viable solution for many inherited and acquired disorders. Hematopoietic stem cells(HSCs) are a prime cell compartment for gene therapy aimed at correcting blood-based disorders, as well as those amenable to metabolic outcomes that can effect cross-correction. While some resounding clinical successes have recently been demonstrated, ample room remains to increase the therapeutic output from HSC-directed gene therapy. In vivo amplification of therapeutic cells is one avenue to achieve enhanced gene product delivery. To date, attempts have been made to provide HSCs with resistance to cytotoxic drugs, to include druginducible growth modules specific to HSCs, and to increase the engraftment potential of transduced HSCs. This review aims to summarize amplification strategies that have been developed and tested and to discuss their advantages along with barriers faced towards their clinical adaptation. In addition, next-generation strategies to circumvent current limitations of specific amplification schemas are discussed.

A facile process to optimize performance of regenerated Nd-Fe-B sintered magnets:Chemo-selective dissolution washing

In this work,the recycled Nd-Fe-B powders and regenerated Nd-Fe-B sintered magnets with low impurity content were successfully prepared from Nd-Fe-B magnet sludge via reduction diffusion(RD)method followed by a chemo-selective dissolution washing proc ess.The chemo-selective dissolution effect of various solution(deionized water,dilute acetic acid solution,NH_(4)Cl-methanol solution) was evaluated by impurity content and magnetic properties of the recycled Nd-Fe-B powder.The NH_(4)Cl-methanol solution can selectively remove impurities with minimal damage to the magnetic phase.Besides,the optimal NH_(4)Cl concentration and liquid-to-solid ratio were investigated.As a consequence,the contents of Ca,O,and H after optimal washing process are reduced to 0.07 wt%,0.31 wt% and 0.22 wt%,respectively.Hence,M_(3) Tis increased to 146.72 emu/g,which is 33% higher than that of the initial sludge.Then,the regenerated Nd-Fe-B sintered magnets with properties of B_(r)=11.66 kG,H_(cj)=16.49 kOe,and(BH)_(m)=31.78 MGOe were successfully prepared by mixing with 40 wt% Nd4Fe14B alloy powders.Compared with the corresponding regenerated magnets washed with deionized water,the remanence and coercivity are increased by 18% and 59%,respectively.

Chemo-selective Suzuki–Miyaura reactions:Synthesis of highly substituted[1,6]-naphthyridines

The Suzuki-Miyaura reaction of methyl-5-bromo-8-（tosyloxy）-1,6-naphthyridine-7-carboxylate（5）,with 2 equiv. of arylboronic acids gave diarylated product, 5,8–diaryl-1,6-naphthyridine-7-carboxylate（7）, whereas 1 equiv. of arylboronic acid resulted in site-selective formation of 5-aryl-8-（tosyloxy）-1,6-naphthyridine-7-carboxylate（8）. The reactions proceeded with excellent chemo-selectivity in favor of the bromide group. Likewise, one-pot reaction with completely different boronic acids by sequential addition produced 1,6-naphthyridine-7-carboxylates,（10） containing two different aryl groups at 5 and 8 positions.

Synthesis of 2H-benzo[g]furo/thieno/pyrrolo[2,3-e]indazoles via Intramolecular Dehydrogenation Photocyclization

A catalyst-,acid-and base-free,environmental-friendly method for synthesis of 2/7-benzo[g]furo[2,3-e]indazoles,2H-benzo[g]-thieno[2,3-e]indazoles and 2H-benzo[g]pyrrolo[2,3-e]indazoles via UV light irradiation of 3-phenyl-4-(2-heteroaryl)pyrazoles(aryl=furanyl,thiophenyl and N-methylpyrrolyl)in EtOH/H_(2)O at room temperature under argon atmosphere was described.

Understanding Mechanistic Differences between 3-Diazoindolin-2-lmines and N-Sulfonyl-1,2,3-Triazoles in the Rh_(2)(ll)-Catalyzed Reactions with Nitrosoarenes

The employment of α-iminometallocarbenes to construct valuable N-containing compounds has attracted significant research interest.Herein,the nucleophilic addition of nitrosoarenes with the α-imino rhodium carbene species(I),which is derived from Rh_(2)(ll)-catalyzed denitrogenation of 3-diazoindolin-2-imines,to produce synthetically useful 2-iminoindolin-nitrones is described.Mechanistically,the N-attack of nitrosoarenes with the carbene site of I is proposed.For the analogous Rh_(2)(ll)-catalyzed reaction of nitrosoarenes with N-sulfonyl-1,2,3-triazoles reported by Li and co-workers(Org.Lett.2014,16,6394),however,the O-attack of nitrosoarenes with the carbene site of α-imino rhodium carbene species(II)is more favorable to occur than the N-attack.The subsequent transformation to yield the product of N-acylamidines is rationalized based on computational studies.The mechanistic differ-ences for the reactions of nitrosoarenes with a-imino rhodium carbene species I and II are discussed.

Construction of isolated Ni sites on nitrogen-doped hollow carbon spheres with Ni-N_(3) configuration for enhanced reduction of nitroarenes

Designing and synthesizing high-efficiency non-precious metal-based catalysts having uniform active sites increases the reactivity and selectivity of materials and provides a platform for an in-depth understanding of their catalytic reaction mechanism.In this study,we provided an approach for fabricating isolated nickel single-atom sites(Ni SAs)with high loading(4.9 wt.%)stabilized on nitrogen-doped hollow carbon spheres(NHCS)using a core–shell structured Zn/Ni bimetallic zeolitic imidazolate framework(ZIF)composite as the sacrificial template.The as-fabricated Ni SAs/NHCS catalyst shows superior activity,selectivity,and recycling durability for the catalytic transfer hydrogenation of nitrobenzene to aniline,thus achieving 100%yield of aniline with a turn-over frequency(TOF)value as high as 29.9 h^(−1) under mild conditions.This TOF value is considerably superior to the supported Ni nanoparticle catalysts.The experiments designed show that the hollow structure feature of NHCS facilitates accessible active sites and mass transfer,which thus contributes to the enhancement of the catalytic performance of Ni SAs/NHCS.Density functional theory calculations show the high chemo-selectivity and activity of the Ni SAs catalyst,arising from the unique role of the single Ni-N3 site on simultaneously activating the H donor(N_(2)H_(4))and substrate,as well as the hydrogenation of the–NOH group as the rate-determining step.