SOLVENTLESS CYCLOCONDENSATIONS BETWEEN 1-NAPHTHOL AND BENZILS

In the absence of organic solvents,the Lewis acid catalyzed cyclocondensation reactions between 1-naphthol and benzils gave 3-aryl-3-aryl'naphtho[1,2-b]furan-2(3H)-ones(NFs) in good yields(62%～70%)An electrophilic substitution mechanism involving formation of n-EPD/v- EPA complexes and rearrangement of aryl group was proposed.

A catalysis study of mesoporous MCM-41 supported Schiff base and CuSO_4·5H_2O in a highly regioselective synthesis of 4-thiazolidinone derivatives from cyclocondensation of mercaptoacetic acid

Mesoporous MCM-41 supported Schiff base and Cu SO4· 5H2 O shows high catalytic activity in the cyclocondensation of mercaptoacetic acid with imines（or aldehydes and amines） to afford pharmaceutically important thiazolidinone derivatives. The catalytic reactions involving twocomponents or three-components afforded the desired product in high yields（up to 98% and 99%）.Moreover, the catalyst works well with respect to recyclability, giving the product in 85% and 83% yields after recycling six times.

N-Heterocyclic Carbene-Catalyzed All Carbon-[4+2] Cyclocondensation of α,β-Unsaturated Acyl Chlorides with 3-Alkylenyloxindoles

Although the NHC-catalyzed cyclization reactions have been well established for the synthesis of various heterocycles,the corresponding all carbon cyclization reaction for the synthesis of carbocycles is far less established.In this note,the NHC-catalyzed all carbon[4+2]cyclocondensation of α,β-unsaturated acyl chlorides and 3-alkenyloxindoles was developed to give the corresponding spirocarbocyclic oxindoles in good yield with good to high diastereoselectivities.

Clean heterocyclic synthesis in water:I_2/KI catalyzed one-pot synthesis of quinazolin-4(3H)-ones

Oxidative cyclocondensation of o-aminobenzamide with various aldehydes in water using I2/KI as catalyst and oxidizing agent is carded out giving the corresponding quinazolin-4（3H）-ones 3a-n in good to excellent yields.

A facile one-pot synthesis of new thieno-[2,3-d]pyrimidine-2,4(1H,3H)-dione derivatives

A facile one-pot synthesis of new 3-arylthieno[2,3-d]pyrimidine-2,4（1H,3H）-diones via base-catalyzed cyclocondensation of ethyl 2-amino-4,5-dimethylthiophene-3-carboxylate with aryl isocyanates is described.

Synthesis of 2H-3,1-pyrazolo[3,4-e]oxazines via a new conversion of Friedlander reaction

2H-3,l-Pyrazolo[3,4-e]oxazines (5a-c) and tacrine analogies (6a-c) were designed and prepared using 5-amino-4-cyanopyrazole (7) and cycloketones (2a-c) as reactants. The study demonstrated that the new conversion existed in the Friedlander reaction of o-aminocyanopyrazole with cycloketones. (C) 2007 Jia Rong Li. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.

ZnO-beta zeolite:As an effective and eco-friendly heterogeneous catalyst for the synthesis of benzothiazole derivatives

A cheap and recyclable ZnO-beta zeolite was used as catalyst for the synthesis of benzothiazole derivatives.This method provides several advantages such as environmental friendliness,short reaction times,high yields,simple work-up procedure and catalyst was successfully reused for four cycles without significant loss of activity.

New conversion of Friendlnder reaction of 3-amino-1H-benzo[f]chromene-2-carbonitriles with cyclohexanone

Two different skeletons of heterocyclic compounds, quinoline and quinazolinone analogs could be obtained by a novel one-pot synthesis from substituted 3-amino- 1H-benzo[f]chromene-2-carbonitrile derivatives and cyclohexanone in DMF in the catalyst of anhydrous Zinc chloride under reflux. A plausible mechanism was proposed. 2007 Jia Rong Li. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.

Synthesis, Crystal Structure and DNA Interaction Study of 3-(2-(3,5-Diphenyl-4,5-dihydropyrazol-1-yl)thiazol-4-yl)-2H-chromen-2-one

A new compound 3-（2-（3,5-diphenyl-4,5-dihydropyrazol-1-yl）thiazol-4-yl）-2Hchromen-2-one was synthesized by cyclocondensation of 3,5-diphenyl-4,5-dihydropyrazole-1-carbothioamide with 3-（2-bromoacetyl）-2H-chromen-2-one in ethanol at reflux for 2hrs. The compound was characterized by IR, 1H-NMR, 13C-NMR and single-crystal X-ray diffraction analysis. The newly synthesized compound（C27H19N3O2S） crystallizes in the triclinic system, space group P1 with a = 5.2476（6）, b = 18.289（2）, c = 23.115（3） , α = 93.546（7）, β = 94.715（6）, γ = 92.347（7）°, V = 2204.3（4）3, Z = 4, Mr = 449.51, crystal size = 0.38 mm × 0.22 mm × 0.16 mm,（I 2σ（I）） = 35317, 9736, 3785, Rint = 0.081,（Δρ）max = 0.19 and（Δρ）min = –0.24 e·-3. DNA interaction studies revealed that the target compound strongly interacts with DNA through an intercalation binding mode and the binding constant of the compound is 7.45 × 104 M-1.

Synthesis and Spectral Characterization of Novel 2-Pyrazoline and Bis-2-Pyrazoline Containing Quinoline Moiety

Eight new compounds containing in their structures substituted quinoline and pyrazole entity were synthesized in good to excellent yield by cyclocondensation reaction of chalcones and hydrazine hydrate. This reaction was conducted in formic acid in presence of BF3·Et2O or in acetic acid. These approaches were extended to bis-chalcones, which delivered functionalized bispyrazolines. The structures of the prepared compounds were confirmed by IR, 1HNMR, 13CNMR and mass spectral analysis.

Synthesis of 2,3-dihydroquinazolin-4(1H)-ones catalyzed by a-chymotrypsin

We discovered that a-chymotrypsin has a promiscuous ability to catalyze the cyclocondensation of aromatic and aliphatic aldehydes with 2-aminobenzamides to afford the corresponding 2,3-dihydroquinazolin-4（1H）-ones successfully in high yields（90%–98%） under alcohol solvent. The catalytic activity of a-chymotrypsin was evaluated through investigating the temperature, the enzyme loading and the ratio of substrates in the enzyme-catalyzed reactions. The present method proves to be efficient and environmentally friendly in terms of short reaction time, high yield, green catalyst and the clean products obtained without further purification processes.

Polarized Ketene Dithioacetals-Versatile Synthons for Different Heterocycles

The reactivity of polarized ketene dithioacetals to develop a variety of heterocycles under different conditions was studied.

A facile synthesis of 6-amino-2H, 4H-pyrano[2,3-F]pyrazole-5-carbonitriles in deep eutectic solvent

A convenient synthesis of 6-amino-2H,4H-pyrano[2,3-F]pyrazole-5-carbonitriles has been accomplished by one pot four-component cyclocondensation of aromatic aldehydes（1a-o） malanonitrile（2）, ethyl acetoacetate（3）, and hydrazine hydrate（4） in freshly prepared deep eutectic solvent, DES（choline chloride：urea）. This protocol has afforded corresponding pyrano[2,3-F]pyrazoles in shorter reaction time with high yields, and it avoids the use of typical toxic catalysts and solvents.

Microwave Irradiation for Accelerating Synthesis of Diarylimidizo[1,5-a]pyrimidine Based on Isoflavones

Microwave irradiation was used to accelerate the cyclocondensation of i soflavones and 5-amino-1H-imidazole- 4-carboxamide in the presence of sodium hydroxide to produce 3,4-diphenyl-imidazo[ 1,5-a]pyrimidines in good to moderate yields.

Synthesis of 5,6-Diarylpyridin-2（1H）-ones from Isoflavones

A simple method for the cyclocondensation of substituted isoflavones with cyanoacetamide in the presence of sodium hydroxide to give an array of 3-cyano-5,6-diarylpyridin-2（1H）-ones in good yields is reported.

A practical synthesis of novel hydroxyl-substituted macrocyclic tri-,tetra- and hexa-amines

Macrocyctic tri- and tetra-amines containing a hydroxyl group in the ring have been prepared in moderate yields by a. 1:1 cyclocondensation of 1,3-dichloro-2-propanol with the disodium salt of N-tosylated diethylenetriamine and triethylenetetraamine. In the case of condensation of 1,3-dichoro-2-propanol with the disodium salt of N-tosylated diethylenetriamine, the 2:2 cyclocondensation product, dihydroxyl macrocyclic hexaamine, was also isolated.