Xiu-Qing Song

Improved synthesis of diethyl 2,6-dimethyl-4-aryl-4H-pyran-3,5-dicarboxylate under ultrasound irradiation.

Diethyl 2,6-dimethyl-4-aryl-4H-pyran-3,5-dicarboxylates (1) have been synthesized by the reaction of aryl aldehyde and 1,3-diketone catalyzed by ZnCl(2) under ultrasound irradiation. The effects of changes in the ultrasonic power, temperature, and reaction time are discussed. With the optimized reaction conditions, various aryl aldehydes were used to synthesize 4H-pyrans (1) under the influence of ultrasound irradiation. Compared with the conventional thermal methods, the remarkable advantages of this method are the simple experimental procedure, shorter reaction time and high yield of product.

[3 + 2] Cycloaddition of Oxazol-5-(4H)-ones with Nitrones for Diastereoselective Synthesis of Isoxazolidin-5-ones

In the presence of TMSCl, the [3 + 2] cycloaddition of oxazol-5-(4H)-ones with nitrones proceeded smoothly and furnished the desired isoxazolidin-5-ones with high diastereoselectivities in reasonable chemical yields. The chemical structure of the title compounds was firmly confirmed by X-ray single-crystal structure analysis.

Facile access to novel 1,2,4-oxadiazinan-5-ones via [3 + 3] cycloaddition of in situ generated azaoxyallyl cations with nitrones

In the presence of Na2CO3, azaoxyallyl cations in situ generated from α-halohydroxamates with nitrones readily underwent [3 + 3] cycloaddition, and gave rise to 1,2,4-oxadiazinan-5-one derivatives in 56–99% chemical yields. The chemical structure of the title compounds was unambiguously identified by X-ray single crystal structure analysis.

Direct access to non-aromatic 1,2,3,6-tetrahydro-1,2,3,4-tetrazines via [4 + 2] cycloaddition of α-halogeno hydrazones with azodicarboxylic acid derivatives

In the presence of K2CO3, the [4 + 2] cycloaddition of α-halogeno hydrazones with azodicarboxylic acid derivatives proceeded efficiently, and delivered novel non-aromatic 1,2,3,6-tetrahydro-1,2,3,4-tetrazines in moderate to excellent chemical yields.

Highly diastereoselective synthesis of imidazolidine-dispirooxindoles via three-component [3 + 2] cycloadditions of isatins, 2-(aminomethyl)pyridine and isatin-based imines

In the presence of Et3N, the [3 + 2] cycloaddition of isatins, 2-(aminomethyl)pyridine and isatin-based imines proceeded readily, and furnished novel imidazolidine-dispirooxindoles in up to 84% yield with up to >99:1 diastereoselectivity. The relative configuration of the imidazolidine-dispirooxindoles was firmly confirmed on the basis of X-ray single crystal structure analysis. The reaction mechanism was assumed to account for the diastereoselective formation of the imidazolidine-dispirooxindoles.

Facile construction of novel imidazolidine-spirooxindoles via diastereoselective cycloaddition of N-acylhydrazine-derived imines with 3-isothiocyanato oxindoles

In the presence of 10 mol% of Na2CO3, the desired imidazolidine-spirooxindoles were obtained in 81–99% yield with up to 99 : 1 dr by means of the diastereoselective [3 + 2] cycloaddition of N-acylhydrazine-derived imines with 3-isothiocyanato oxindoles. Single-crystal X-ray structure analysis was conducted to determine the relative stereochemistry of the imidazolidine-spirooxindoles. Diastereoselective access to the imidazolidine-spirooxindoles was hypothesized by the proposed mechanism.

Preparation of 4,7-diphenyl-1,10-phenanthroline-2,9-dicarboxylic acid catalyzed by iron(III)porphyrins with (diacetoxyiodo)benzene

Using iron(III)porphyrins in combination with (diacetoxyiodo)benzene allows for the conversion of 2,9-bis(bromomethyl)-4,7-diphenyl-1,10-phenanthroline into 4,7-diphenyl-1,10-phenanthroline-2,9-dicarboxylic acid. This method provides a cost-effective and environmentally-friendly oxidation procedure using less toxic PhI(OAc)2 and biologically relevant iron(III)porphyrins. The catalytic activity of five kinds of iron-metallated functional porphyrins were investigated using different oxidants, including air, H2O2, PhI(OAc)2, PhIO and NaClO. Our results showed that the use of T(p-NO2)PPFeCl with PhI(OAc)2 as the oxidant in the presence of water displays remarkable activity for the desired oxidation reaction. The generality of this method was examined by synthesizing the carboxylic acids of pyridines and quinolines.

1,3-Dipolar [3 + 3] cycloaddition of α-halohydroxamate-based azaoxyallyl cations with hydrazonoyl chloride-derived nitrile imines

Promoted by Et3N, the 1,3-dipolar [3 + 3] cycloaddition of α-halohydroxamate-based azaoxyallylcations with hydrazonoyl chloride-derived nitrile imines occurred efficiently, and furnished desired products in acceptable chemical yields. The chemical structure of the title compounds was firmly confirmed by an X-ray single crystal structure analysis.

Design and synthesis of 4-(2,3-dihydro-1 H -benzo[ d ]pyrrolo[1,2- a ]imidazol-7-yl)- N -(5-(piperazin-1-ylmethyl)pyridine-2-yl)pyrimidin-2-amine as a highly potent and selective cyclin-dependent kinases 4 and 6 inhibitors and the discovery of structure-activity relationships

Cyclin-dependent kinases 4/6 play an important role in regulation of cell cycle, and overexpress in a variety of cancers. Up to now, new CDK inhibitors still need to be developed due to its poor selectivity. Herein we report a novel series of 4-(2,3-dihydro-1H-benzo[d]pyrrolo[1,2-a]imidazole-7-yl)-N-(5-(piperazin-1-ylmethyl)pyridine-2-yl)pyrimidin-2-amine anologues as potent CDK 4/6 inhibitors based on LY2835219 (Abemaciclib). Compound 10d, which exhibits approximate potency on CDK4/6 (IC50 = 7.4/0.9 nM), has both good pharmacokinetic characters and high selectivity on CDK1 compared with LY2835219. Overall, compound 10d could be a promising candidate and a good starting point as anticancer drugs.

Construction of 2,3,4,5-tetrahydro-1,2,4-triazines via [4 + 2] cycloaddition of α-halogeno hydrazones to imines

In the presence of sodium carbonate, the [4 + 2] cycloaddition of α-halogeno hydrazones to imines proceeded readily, and furnished 2,3,4,5-tetrahydro-1,2,4-triazines in moderate to high chemical yields.