Xuesen Fan

Tandem reactions leading to bicyclic pyrimidine nucleosides and benzopyran-4-ones.

A novel, rapid, and efficient synthesis of bicyclic pyrimidine nucleosides and benzopyran-4-ones through oxidation of homopropargyl alcohols and subsequent isomerization, intramolecular addition of enol to allenic ketone has been developed. This methodology provides an efficient and promising approach to the structurally and pharmaceutically interesting pyrano[2,3-d]pyrimidine-2,5-dione nucleoside and benzopyran-4-one derivatives.

Tandem reactions of 1,2-allenic ketones leading to substituted benzenes and α,β-unsaturated nitriles.

One-pot double Michael addition/intramolecular aldol reaction/decarboxylation of 1,2-allenic ketones with cyanoacetate offers an efficient and convenient approach to highly functionalized benzenes. With 2-substituted cyanoacetates, the reaction proceeds via a different tandem process to afford α,β-unsaturated nitriles effectively.

Tunable synthesis of 3-acyl-2-naphthols and 3-substituted isocoumarins via Jones reagent promoted cascade reactions of 2-(4-hydroxy-but-1-ynyl)benzaldehydes.

Novel and efficient synthesis of 3-acyl-2-naphthols and 3-substituted isocoumarins via the tunable cascade reactions of 2-(4-hydroxy-but-1-ynyl)benzaldehydes have been developed. Treatment of 2-(4-hydroxy-but-1-ynyl)benzaldehydes with 0.7 equiv of Jones reagent in CH3CN and subsequent purification through column chromatography on silica gel pre-eluted with Et3N afforded 3-acyl-2-naphthols with high efficiency. When the same substrates were treated with 3 equiv of Jones reagents in acetone, on the other hand, 3-substituted isocoumarins could be obtained in good yields.

InCl3·4H2O/TMSCl-catalysed aldol reaction of aromatic aldehydes with cycloalkanones in ionic liquid medium

An efficient and practical preparation of α,α′-bis(substituted benzylidene) cycloalkanone derivatives from cycloalkanones and aromatic aldehydes promoted by InCl3•4H2O/TMSCl in ionic liquid ([bmim][BF4]) is described.

Samarium chloride catalysed Biginelli reaction: one-pot synthesis of 3,4-dihydropyrimidin-2(1H)-ones

An efficient synthesis of 3,4-dihydropyrimidin-2(1H)-one derivatives using samarium chloride as a catalyst from aldehyde, β-keto ester and urea or thiourea in ethanol is described; compared to the classical Biginelli method, this new method has the advantages of good yields and milder reaction conditions.

MWI-promoted preparation of 4H-thiopyran derivatives through one-pot multi-component reactions

One-pot reaction of aromatic aldehydes, cyanothioacetamide and malononitrile under microwave irradiation proved to be an efficient way for the synthesis of 2,6-diamino-4-aryl-4H-thiopyran-3,5-dicarbonitriles without any added catalyst.

Samarium diiodide mediated regeneration of 1,2-benzene-diamine and preparation of benzimidazolin-2-ones from 2,1,3-benzo-thia-diazoles

On treatment with SmI2 in THF and in the presence of methanol, 2,1,3-benzothiadiazoles underwent reductive N–S bond cleavage leading to 1,2-benzenediamines in high yields. Without methanol but in the presence of triphosgene, benzimidazolin-2-ones were obtained in moderate yields under mild conditions.

NOVEL AND EFFICIENT SYNTHESIS OF PYRAZOLO[3,4-b]PYRIDIN-6-ONES OR THEIR HYDROGENATED DERIVATIVES THROUGH ONE-POT REACTION IN IONIC LIQUID

- Pyrazolo[3,4-b]pyridm-6-ones or their hydrogenated derivatives were obtained selectively and conveniently through one-pot reaction of aldehyde, ethyl cyanoacetate and 5-amino-3-methyl-l-phenylpyrazole in [bmim][BF 4 ] with or without ferric chloride at different temperatures. Advantages of this novel method include high yield, mild conditions, simple procedure and good selectivity. In addition, the ionic liquid used can be easily recovered and effectively reused.

SmI2-mediated reduction of phenacyl azides: a novel preparation of 2,4-diarylpyrroles

A novel reductive cyclisation of phenacyl azides brought about by samarium iodide is described in this paper. By this process several 2,4-diarylpyrroles have been prepared.

Facile preparation of 2,3-disubstituted indole derivatives through low-valent titanium induced intramolecular reductive coupling reactions of acylamido-carbonyl compounds

An efficient synthesis of 2,3-disubstituted indole derivatives through low-valent titanium induced reductive cyclisation of suitably substituted acylamido-carbonyl compounds is described.