Fabrication of microfluidics structures on different glasses by simplified imprinting technique

Imprinting technique is an efficient method for fabricating microstructures for microfluidics and lab-on-chip applications. However such technique is not commonly used for glass based microstructures fabrication. In this study, microstructures were transferred completely and successfully from a nickel alloy stamp to different glasses such as sodalime glass, Pyrex glass, SGBN glass and magneto optical glasses, using imprinting technique. Furthermore, the traditional vacuum hot press for imprinting was replaced with the conventional electric furnace which increases the cost efficiency and simplicity greatly. Using specific mold in the conventional furnace, the mass production of microstructured glass chips can be realized.     

Chiral Brønsted Acid from Chiral Phosphoric Acid Boron Complex and Water: Asymmetric Reduction of Indoles

A new chiral Brønsted acid, generated in situ from a chiral phosphoric acid boron (CPAB) complex and water, was successfully applied to asymmetric indole reduction. This “designer acid catalyst”, which is more acidic than TsOH as suggested by DFT calculations, allows the unprecedented direct asymmetric reduction of C2‐aryl‐substituted N‐unprotected indoles and features good to excellent enantioselectivities with broad functional group tolerance. DFT calculations and mechanistic experiments indicates that this reaction undergoes C3‐protonation and hydride‐transfer processes. Besides, bulky C2‐alkyl‐substituted N‐unprotected indoles are also suitable for this system.     

Exonuclease I aided enzyme-linked aptamer assay for small-molecule detection

A novel enzyme-linked aptamer assay (ELAA) with the aid of Exonuclease I (Exo I) for colorimetric detection of small molecules was developed. The fluorescein isothiocyanate (FITC)-labeled aptamer was integrated into a double-stranded DNA (dsDNA). In the presence of target, the binding of aptamer with target protected the aptamer from Exo I degradation, which resulted in the FITC tag remaining on the aptamer. Then, the anti-FITC-HRP conjugate was used to produce an optically observable signal. By monitoring the color change, we were able to detect two model molecules, ATP and L-argininamide, with high selectivity and high sensitivity even in the serum matrix. It is expected to be a simple and general ELAA method with wide applicability.

Surfactant–Thermal Method to Synthesize a Novel Two‐Dimensional Oxochalcogenide

A new two‐dimensional (2D) oxosulfide, (N₂H₄)₂Mn₃Sb₄S₈(μ₃‐OH)₂ ( 1 ), has been successfully synthesized under surfactant–thermal conditions with hexadecyltributylphosphonium bromide as the surfactant. Compound 1 has a layered structure and contains a novel [Mn₃(μ₃‐OH)₂]_n chain along the b‐axis. The photocatalytic activity for compound 1 has been demonstrated under visible‐light irradiation and continuous H₂ evolution was observed. Our results indicate that surfactant–thermal synthesis could be a promising method for growing novel crystalline oxochalcogenides with interesting structures and properties.     

The supertristeroids: large, chiral, molecular bowls prepared by trimerization of pentacyclic steroidal ketones

Robinson annulation of coprostanone (1) at the 2,3- and 3,4-positions gave two pentacyclic enones (7 and 10) that contain A/B-cis-fused ring junctions. Reduction of these enones gave the pentacyclic steroidal ketones 2 alpha,3beta- (8) and 2 alpha,3 alpha-(3'-oxocyclohexano)-5 beta-cholestane (9) and 4 alpha,3beta- (11) and 4 alpha,3 alpha-(3'-oxocyclohexano)-5 beta-cholestane (12). The structures of compounds 8, 9, and 11 were unambiguously established by X-ray analysis. TiCl4-promoted trimerization of compounds 8 and 11 gave the "supertristeroids" 4 and 5, respectively: large (C93) chiral, hydrocarbon clefts with C3-symmetric pockets approximately 12 A in diameter.     

Chiral Brønsted Acid from Chiral Phosphoric Acid Boron Complex and Water: Asymmetric Reduction of Indoles

A new chiral Brønsted acid, generated in situ from a chiral phosphoric acid boron (CPAB) complex and water, was successfully applied to asymmetric indole reduction. This “designer acid catalyst”, which is more acidic than TsOH as suggested by DFT calculations, allows the unprecedented direct asymmetric reduction of C2-aryl-substituted N-unprotected indoles and features good to excellent enantioselectivities with broad functional group tolerance. DFT calculations and mechanistic experiments indicates that this reaction undergoes C3-protonation and hydride-transfer processes. Besides, bulky C2-alkyl-substituted N-unprotected indoles are also suitable for this system.     

Stereospecific 1,4‐Metallate Shift Enables Stereoconvergent Synthesis of Ketoximes

Reported herein is a stereospecific 1,4‐metallate rearrangement for single‐geometry ketoxime synthesis from oxime chlorides and arylboronic acids. This strategy exhibits broad substrate scope with excellent stereoselectivity under mild reaction conditions. In comparison with the conventional approaches, each configuration of unsymmetric diaryl oximes, as well as the thermodynamically less stable Z isomer of aryl alkyl ketoximes can be selectively and exclusively obtained. The reactivities of unsymmetric diaryl oximes and the Z isomer of aryl alkyl oximes, a class of underexplored molecules, enables efficient access to the corresponding isoquinolines, isoquinoline N‐oxides, and amides having a single configuration.