Xiao-Hong Zhang

Synthesis of Isoxazolo[5,4-b]pyridines by Microwave-Assisted Multi-Component Reactions in Water

A series of new polycyclic-fused isoxazolo[5,4-b]pyridines were obtained by a one-pot tandem reaction under microwave irradiation in water. Without any use of additional reagent or catalyst, the synthetic protocol represents a green one and makes this methodology suitable for library synthesis in drug discovery efforts.

New potential inhibitors of DNA topoisomerase. Part II: Design and synthesis of α-lapachone derivatives under microwave irradiation

A new series of potential inhibitors of DNA topoisomerase II were synthesized from facile materials (aromatic aldehydes, Meldrums acid and 2-hydroxynaphthalene-1,4-dione) under microwave irradiation. The method provides a valuable tool in designing new and more potent cytotoxic analogues. This procedure is advantageous both economically and environmentally.

Design and microwave-assisted synthesis of naphtho[2,3-f]quinoline derivatives and their luminescent properties.

A sequential three-component reaction of an aromatic aldehyde with an equimolar amount of 2-aminoanthracene and cyclic 1,3-dicarbonyl compounds (such as tetronic acid, 5,5-dimethyl,3-cyclohexanedione, 1,3-indanedione, 3H-chromene-2,4-dione, quinoline-2,4(1H, 3H)-dione and barbituric acid) in acidic medium under microwave irradiation has been developed. In this one-pot reaction, a series of unusual fused heterocyclic compounds, naphtho[2,3-f]quinoline derivatives, were synthesized. This method has the advantages of operational simplicity, increased safety for small-scale fast synthesis, and minimal environmental impact. Most distinctively, this new class of naphtho[2,3-f]quinoline derivatives exhibit good luminescent properties in the ethanol solution, which can be used potentially as organic electroluminescent (EL) media.

Facile Diversity-Oriented Synthesis of Novel Dipeptide Mimetic Compounds Containing Bioactive Molecular Skeletons under Microwave Irradiation

The diversity-oriented synthesis of dipeptide mimetic compounds embedded with bioactive molecular skeletons have been successfully established via microwave-assisted reactions between various 4-arylidene-2-phenyloxazol-5(4H)-ones and a broad scope of amines including aliphatic, aromatic, and heteroaromatic ones. This synthetic approach has prominent features of short reaction time, high yields, operational simplicity, as well as widespread applications, leading to a facile and straightforward access to structurally diverse dipeptide analogues with potential bioactivities. Moreover, the preliminary evaluation on the cytotoxic activity of this type of dipeptide derivatives has resulted in the finding of five compounds with stronger cytotoxicity than doxorubicin hydrochloride at the concentration of 10 μg/mL.

Efficient microwave-assisted synthesis of novel 3-aminohexahydrocoumarin derivatives and evaluation on their cytotoxicity.

The efficient synthesis of novel 3-aminohexahydrocoumarin derivatives with high diastereoselectivity, wide applicability, short reaction time, high yields as well as operational simplicity was achieved via microwave-assisted reactions of dimedone or cyclohexane-1,3-dione with 4-arylidene-2-phenyloxazol-5(4H)-ones. Moreover, these novel compounds were subject to the test of in vitro cytotoxicity to carcinoma SW1116 and SGC7901 cells. Seven compounds showed stronger cytotoxicity to carcinoma SW1116 cells than doxorubicin hydrochloride at the concentration of 10 ug/mL. Nearly all the tested compounds exhibited strong or moderate cytotoxicity to SGC7901 cells with IC(50) values from 5.127 to 0.158 ug/mL.

One-Step Efficient Synthesis of Pyrazolo[3,4-f]quinoline Derivatives Under Microwave Irradiation

A series of new pyrazolo[3,4-f]quinoline derivatives were synthesized by multicomponent reactions of equimolar amounts of aromatic aldehydes 1, barbituric acids 2 (barbituric acid or 1,3-dimethyl barbituric acid), and 5-aminoindazole 3 in mixed solvent of glacial acetic acid and ethylene glycol (2:1, v/v) without catalyst under microwave irradiation. This one-pot protocol has the advantage of good yields (91–94%), simple workup procedure, and short reaction times (5–6 min).

Microwave-assisted combinatorial synthesis of new 3-pyrimidin-5-ylpropanamides via a solvent-dependent chemoselective reaction.

A series of new 3-pyrimidin-5-ylpropanamides was selectively synthesized via a microwave-assisted, chemoselective reaction of arylidene-Meldrums acid, 6-hydroxypyrimidin-4(3H)-one, and structurally diverse amines including (S or R)-1-phenylethanamine, cyclohexanamine, and cyclopentanamine depended on nature of solvents. In this reaction, the utilization of HOAc as a solvent leads to 3-pyrimidin-5-ylpropanamides, whereas water as reaction media results in the spiro[5.5]undecane-1,5,9-triones from same starting materials. This method has the advantages of short synthetic route, operational simplicity, increased safety for small-scale high-speed synthesis, and minimal environment impact.

Green, Microwave-Assisted Approach to the Synthesis of Arylidene-Substituted Spiro[4,5]decan-8-one Derivatives in Water

A green approach to the synthesis of arylidene-substituted spiro[4,5]decan-8-one derivatives was successfully realized via the mild, base-catalyzed reaction of aromatic aldehydes with 1,4-dioxa-spiro[4.5]decan-8-one in water under microwave irradiation. This protocol has the prominent advantages of environmental friendliness, short reaction time, excellent yields, low cost, easy operation, and broad scope of applicability.

2-Amino-4-(2-chloro­phen­yl)-5,10-dioxo-5,10-dihydro-4H-benzo[g]chromene-3-carbonitrile

In the molecule of the title compound, C20H11ClN2O3, the pyran ring adopts a flattened-boat conformation. In the crystal structure, intermolecular N—H⋯N and N—H⋯O hydrogen bonds generate edge-fused R 2 2(12) and R 2 2(14) ring motifs; the hydrogen-bonded motifs are linked to each other, forming a three-dimensional network. A π–π contact [centroid-to-centroid distance = 3.879u2005(3)u2005Å] between the chlorophenyl rings may further stabilize the structure.