Yumei Xiao

Highly enantioselective Friedel–Crafts alkylation of indoles and pyrrole with β,γ-unsaturated α-ketoesters catalyzed by heteroarylidene-tethered bis(oxazoline) copper complexes

The simple and cheap chiral catalyst, heteroarylidene-tethered Ph-bis(oxazoline)-Cu(OTf)(2), can efficiently catalyze the asymmetric F-C alkylation of indoles and pyrrole with β,γ-unsaturated α-ketoesters. The 3-indolyl adducts were obtained in up to >99% ee. Moreover, the 2-pyrrolyl adducts were achieved in up to 92% ee for the first time.

Design, synthesis and antifungal/insecticidal evaluation of novel cinnamide derivatives.

Twenty novel cinnamamide derivatives were designed and synthesized using as lead compound pyrimorph, whose morpholine moiety was replaced by β-phenylethylamine. All the compounds were characterized by their spectroscopic data. The fungicidal and insecticidal activities were also evaluated. The preliminary results showed that all the title compounds had certain fungicidal activities against seven plant pathogens at a concentration of 50 μg/mL, and compounds 11a and 11l showed inhibition ratios of up to 90% against R. solani. Most of the title compounds exhibited moderate nematicidal activities. In general, the morpholine ring may be replaced by other amines and a chlorine atom in the pyridine ring is helpful to fungicidal activity.

Design and Functional Characterization of a Novel Abscisic Acid Analog

The phytohormone abscisic acid (ABA) plays a crucial role in mediating plant growth and development by recruiting genetically redundant ABA receptors. To overcome its oxidation inactivation, we developed a novel ABA analog named 2′,3′-benzo-iso-ABA (iso-PhABA) and studied its function and structural characterization with A. thaliana ABA receptors. The (+)-iso-PhABA form showed much higher ABA-like activities than (+)-ABA including inhibitory effects on the seed germination of lettuce and A. thaliana, wheat embryo germination and rice seedling elongation. The PP2C (protein phosphatases 2C) activity assay showed that (+)-iso-PhABA acted as a potent and selective ABA receptor agonist, which is preferred to PYL10. In some cases, (−)-iso-PhABA showed moderate to high activity for the PYL protein inhibiting PP2C activity, suggesting different mechanisms of action of iso-PhABA and ABA. The complex crystal structure of iso-PhABA with PYL10 was determined and elucidated successfully, revealing that (+)-iso-PhABA was better coordinated in the same binding pocket compared to (+)-ABA. Moreover, the detailed interaction network of iso-PhABA/PYL10 was disclosed and involves hydrogen bonds and multiple hydrophobic interactions that provide a robust framework for the design of novel ABA receptor agonists/antagonists.

A highly efficient regioselective addition of acetylides to enediones based on steric effects.

A simple and efficient strategy for the synthesis of 1-ethynylcyclohex-2-enol derivatives was developed utilizing regioselective addition of acetylides to enediones based on steric effects. Further investigation of the substrate scope of enediones indicated that all the addition reactions ocurred in good yield.

A convenient one-pot synthesis of arene-centered tris(thiazoline) compounds

A simple and practical one-pot synthesis of novel enantiopure tris(thiazoline) compounds was documented. The desired products were obtained in moderate to good yields through three steps from commercially available 1, 3, 5-benzenetricarboxylic acid or 2, 4, 6-pyridinetricarboxylic acid, and chiral amino alcohols. Only one column chromatographic purification was needed for the three steps.

Synthesis and Fungicidal Activity of Thiazoline Derivatives Containing Halogenated Indolyl Moiety

Abstract A series of novel 1,3-thiazoline derivatives containing a 5- or 6-position halogenated indole moiety were synthesized via a one-pot and three-step reaction. Their structures were confirmed by spectroscopic methods. The fungicidal activities of all the title compounds were evaluated. Most of them exhibited moderate to high activity against eight plant pathogens at the concentration of 50 ug/mL. Generally the fungicidal activity of fluorinated indolyl thiazolines was higher than that of chlorinated indolyl thiazoline derivatives. Supplemental materials are available for this article. Go to the publishers online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file. GRAPHICAL ABSTRACT

Synthesis and Biological Activity of 2′,3′-iso-Aryl-abscisic Acid Analogs

2′,3′-iso-Benzoabscisic acid (iso-PhABA), an excellent selective abscisic acid (ABA) analog, was developed in our previous work. In order to find its more structure-activity information, some structural modifications were completed in this paper, including the substitution of phenyl ring and replacing the ring with heterocycles. Thus, 16 novel analogs of iso-PhABA were synthesized and screened with three bioassays, Arabidopsis and lettuce seed germination and rice seedling elongation. Some of them, i.e., 2′,3′-iso-pyridoabscisic acid (iso-PyABA) and 2′,3′-iso-franoabscisic acid (iso-FrABA), displayed good bioactivities that closed to iso-PhABA and natural (+)-ABA. Some others, for instance, substituted-iso-PhABA, exhibited certain selectivity to different physiological process when compared to iso-PhABA or (+)-ABA. These analogs not only provided new candidates of ABA-like synthetic plant growth regulators (PGRs) for practical application, but also new potential selective agonist/antagonist for probing the specific function of ABA receptors.