Suoqin Zhang

H8-BINOL Chiral Imidodiphosphoric Acids Catalyzed Enantioselective Synthesis of Dihydroindolo-/-pyrrolo[1,2-a]quinoxalines

The first enantioselective synthesis of 5,6-dihydroindolo[1,2-a]quinoxalines is achieved by using a newly developed H8-BINOL-type imidodiphosphoric acid catalyst with low catalyst loading through efficient Pictet-Spengler-type reactions of indolyl anilines with ketones. This methodology also generates phenyl-4,5-dihydropyrrolo[1,2-a]quinoxalines with high yields and excellent enantioselectivities. Moreover, this method was utilized to synthesize an HIV-1 inhibitor with high yield and good enantioselectivity through a one-step procedure.

Extraction of steroid saponins from Paris polyphylla Sm. var. yunnanensis using novel ultrahigh pressure extraction technology

A new method of ultrahigh pressure extraction (UPE) was used to extract steroid saponins from Paris polyphylla SM. var. yunnanensis (chonglou) at room temperature. The microstructure of the drug before and after the extraction was studied by scanning electron microscopy (SEM). The mechanism of UPE is discussed and demonstrated based on the results of SEM investigation. The influence of several factors, including solvent type, solvent concentration, UPE pressure, UPE time, and liquid-to-solid ratio, has been studied in order to optimize the extraction process. The optimum extraction takes place with an ethanol concentration of 90%, a pressure of 400 MPa, an extraction time of 2 min, and a liquid-to-solid ratio of 40: 1. In comparison with usual room-temperature extraction at normal pressure, ultrasound-assisted extraction, microwave-assisted extraction, and Sohxlet extraction, the UPE method shows higher efficiency at room temperature.

Organocatalyzed nucleophilic addition of pyrazoles to 2H-azirines: asymmetric synthesis of 3,3-disubstituted aziridines and kinetic resolution of racemic 2H-azirines

The first organocatalytic asymmetric nucleophilic addition of arylpyrazoles to 2H-azirines and kinetic resolution of racemic 2H-azirines have been realized. Chiral aziridines were obtained with up to 98% yields and up to 99.9% ee. Meanwhile, simply changing the ratio of reactants, optically active 2H-azirines were recovered in good yields with excellent enantioselectivities.

Chemical composition and antioxidant activity of essential oil from berries of Schisandra chinensis (Turcz.) Baill

Essential oils of Schisandra chinensis seeds and berries without seeds were separately extracted. A total of 55 compounds were identified in the essential oil of berries without seeds (EOB), representing 85.75% of the total content. A total of 52 compounds were identified in the essential oil of seeds (EOS), representing 89.74% of the total content. For EOB, the top three content compounds were α-cis-bergamotene (10.79%), 4,11-selinadiene (5.28%) and α-cadinol (5.19%), while the top three content compounds of EOS were ylangene (10.16%), β-himachalene (9.46%) and di-epi-α-cedrene (8.92%). The antioxidant activity of the essential oil was tested using the DPPH radical-scavenging method. The antioxidant activity of EOB was higher than EOS. The IC50 values of EOB and EOS were 8.4 and 15.8 mg/mL, respectively. This study concluded that EOB and EOS were not only different in extraction yield but also in chemical composition and antioxidant activity.

Simple and Effective Synthetic Approach to Chiral 2-Amino-4-piperidinyl Pyridine Derivatives

Abstract A facile way has been developed to provide a series of novel chiral N-(4-(piperidin-1-yl)pyridin-2-yl)amide derivatives as potential stereoselective catalysts. The key intermediate, 2-amino-4-piperidinyl pyridine, was obtained by nucleophilic substitution of 2-amino-4-chloropyridine with piperidine in good yields (up to 96%). The total control of enantioselectivity was obtained for the synthesis of L-proline and (R)-1,1′-bi(2-naphthol) derivatives. GRAPHICAL ABSTRACT

(S)‐N‐(1H‐Tetra­zol‐5‐ylmeth­yl)pyrrolidine‐2‐carboxamide dihydrate

In the title compound, C7H12N6O·2H2O, all bond lengths and angles show normal values. The pyrrolidine ring adopts a C1–Cγ-endo conformation. An extensive network of N—H⋯O and O—H⋯O hydrogen bonds stabilizes the crystal packing.

Metal-free hydrogen transfer reduction of 3-hydroxy-3-indolyloxindoles: a novel method for the synthesis of 3,3′-biindolin-2-ones

Herein, a new approach for the synthesis of 3,3′-biindolin-2-ones is reported. The transformation has been successfully performed following a one-step strategy starting from 3-hydroxy-3-indolyloxindoles. The reaction proceeds smoothly under mild conditions and is applicable to a broad scope of substrates. In this process, a number of products were obtained in good to excellent yields (≥99%) using Bronsted acid as a catalyst and benzothiazolines as the hydrogen source.

Synthesis of pennogenyl saponins using three methods

The synthesis of pennogenyl saponins using three important methods of glycosylation is reported in this article. Six correlative compounds (7–12) were first synthesized. As donors (1–6), glycosyl halide, trichloroimidate, and thioglycoside were chosen to study their reaction with the acceptor pennogenin. In these reactions the difference in steric hindrance between 3-OH and 17-OH of pennogenin was utilized skillfully and only the 3-hydroxyl group of pennogenin could be connected with each kind of donors selectively. There was no reaction at the 17-hydroxyl group, which had no protection. The characteristic above makes it convenient to synthesize compounds of pennogenyl saponins.

Novel Catalytic Method for Synthesis of Glycosyl Esters by Combining PTC with DMAP

This article presents a novel catalytic method by combining phase-transfer catalyst, benzyltriethylammonium chloride, with 4-dimethylaminopyridine for the syntheses of glycosyl esters from substituted phenoxyacetic acids and the peracetate of α- D -1-bromosugars to produce eight novel β-glycosyl esters in high yields. The structures of the synthesized compounds were established by IR, MS, 1 H NMR, and 13 C NMR spectra and elemental analyses.

Synthesis and Characterization of Novel-4-Methyl-3-isoxazolidinone Derivatives

Abstract A novel type of acetohydroxyacid synthase inhibitors, 4-methyl-3-isoxazolidinone derivatives of sulfonylurea, was designed and synthesized. The structures of these compounds were confirmed by using MS, NMR, and elemental analysis. The results of preliminary active tests indicate that the compounds show a herbicidal activity.