Chizhong Xia

A simple and effective method for chemoselective esterification of phenolic acids

Abstract A new method for efficient and chemoselective esterification of phenolic acids in KHCO3/alkyl halide/DMF reaction system is described, by which a series of phenoic acid esters were obtained in excellent yields.

Synthesis of α‐Substituted N‐Aryl Acrylamide Derivatives Through Baylis–Hillman Reaction

Abstract N‐aryl acrylamides were found to be the more activated Michael acceptor forBaylis–Hillman reaction than acrylamides and N‐alkyl acrylamides. Treatment of N‐aryl acrylamides with aromatic aldehydes in the presence of DABCO (1,4‐diazabicyclo[2·2·2]octane) afforded the desired Baylis–Hillman products, α‐substituted acrylamide derivatives, which have important applications as novel radical polymerization monomers and biologically important reagents.

A CONVENIENT SYNTHESIS OF IMIDAZOLIUM SALTS AND TRISUBSTITUTED ETHYLENEDIAMINE DERIVATIVES

ABSTRACT A series of 1,2-dimethyl-3-arylsulfonyl1-4,5-dihydroimidazolium iodides (7–11) was prepared by convenient sulfonylation and methylation from commercially available 2-methyl-2-imidazoline. Trisubstituted ethylenediamine derivatives 12–21 were synthesized from the reduction or hydrolysis of imidazolium salts 7–11 in high yield.

REACTIONS OF 2,3-DIARYL-1-METHYL-4,5-DIHYDROIMIDAZOLIUM IODIDES WITH NUCLEOPHILIC REAGENTS

ABSTRACT 2,3-Diaryl imidazolium salts, represented by 1 and 2, reacted with 2-ethanolamine or ethylenediamine to produce 2-aryl oxazolines or imidazolines 5–8 respectively. Their hydrolysis resulted in ring-opened ethylenediamine derivatives 9 and 10. The reduction of 1 and 2 produced partially reduced imidazolidines 11, 12 and 11 reacted further with tryptamine to provide 2,3,4,9-tetrahydro-1-phenyl 1H-pyrido[3,4-b]indole, 13. In all these reactions one-carbon units were successfully transferred to the nucleophilic acceptors, which mimic the one-carbon unit transfer function for tetrahydrofolate coenzymes.

AMINOLYSIS OF 1,2-DIMETHYL- 3-ARYLSULFONYL-4,5-DIHYDROIMIDAZOLIUM IODIDES WITH AROMATIC AMINES

ABSTRACT Reactions of the arylsulfonylimidazolium salts (1–4) with aromatic amines produced N′-aryl-N-methyl-N-(2-arylsulfonylamino)ethylacetamidine monohydroiodides (5–17) in good to excellent yields through a nucleophilic addition and the followed ring-opening mechanism.

Synthesis of functionalized tetrahydro-β-carboline derivatives by modified pictet-spengler reaction

Instead of iminium salt in Pictet-Spengler reaction, a series of indole-bearing secondary enamines were synthesized through one-carbon unit transfer reactions of a tetrahydrofolate coenzyme models with tryptamine, and applied to Pictet-Spengler reaction. Reaction of the secondary enamines in acid conditions produced a series of functionalized tetrahydro-β-carboline derivatives in good to excellent yields.

A Convenient Synthesis of 1‐Tosyl‐3, 4‐Dimethyl Imidazolium Salt and N,N,N′‐Trisubstituted Ethylendiamine Derivatives

Abstract 1‐Tosyl‐3,4‐dimethyl imidazolium iodide 3 was prepared by convenient cyclization, sulfonylation, and methylation from 4‐methyl‐2‐imidazoline, which was obtained by the reaction of ethyl formate with 1,2‐diaminopropane. Monofunctional carbon nucleophiles reacted with 3 to yield a series of N,N,N′‐trisubstituted ethylendiamine derivatives.

NUCLEOPHILIC ADDITION TO 1,2-DIMETHYL-3-ARYLSULFONYL- 4,5-DIHYDROIMIDAZOLIUM IODIDES

ABSTRACT Benzenesulfonamide derivatives 6–11 were prepared from the reactions of arylsulfonylimidazolium iodides 1–5 with malononitrile or nitromethane anions in high yield. The addition product 11 reacted further with tryptamine to produce 2,3,4,9-tetrahydro-1-methyl-1-nitromethyl-1H-pyrido[3,4]indole (12) in excellent yield through Pictet–Spengler type reaction.

A convenient preparation of a series of 2-aryl-substituted imidazolidines through diamine transfer reaction

A series of 2-aryl-substituted imidazolidines were prepared through the simple diamine transfer reactions between 2-alkyl-substituted imidazolidines and aromatic aldehydes under the catalysis of n-butylamine.

Ethyl 2-acetyl-3-[2-(1H-indol-3-yl)­ethyl­amino]­propenoate

Secondary enamines have attracted a great deal of attention in recent years because of their range of applications (Duthaler, 2003; Stanovnik & Svete, 2004; Elassar & El-Khair, 2003). Moreover, functionalized secondary enamine derivatives may enable chemical and biological studies on these derivatives, which will be used in pharmaceutical research. We were therefore interested in the synthesis of secondary enamine derivatives during our investigation of tetrahydrofolate coenzyme models (Li et al., 2004). Tetrahydrofolate is involved in the biological transfer of a carbon unit at different oxidation levels (Blakley, 1969), which can transfer ÐC CÐ or CHÐ groups via mechanisms analogous to those operative in biochemical processes (Bieraugel et al., 1983; Pandit & Bieraugel, 1979).