Journal of Chemical Research

Three component condensation reactions between azaarenes (phenanthridine, quinoline or isoquinoline) and acetylenic esters were undertaken in the presence of phenol derivatives (2,4-di-tert-butylphenol, 2,6-dimethylphenol, 4-methylphenol and 4-chloro-3,5-dimethylphenol) for generation of C-arylation in good yields. The reactions proceeded smoothly at room temperature without using any catalyst.

A rapid and efficient microwave-assisted synthesis method for the preparation of 1,3,4-thiadiazole Schiff base derivatives is described. These 1,3,4-thiadiazole Schiff bases (5a-h) were identified by IR, ¹H NMR, elemental analyses. The target compounds were performed in a shorter reaction time compared with conventional heating methods.

A mild, efficient, and eco-friendly method for the Ugi reaction between a carboxylic acid, an amine, a carbonyl compound and an isocyanide to give a bisamide is described using PEG–H₂O as a solvent. Reactants of poor water-solubility could be used in an aqueous medium without significant decrease in the yield. No side products were observed. The advantages of this protocol are short reaction time and easy isolation of the precipitated product when compared to reactions carried out in methanol.

anti-9-Methoxy[3]metacyclo[3](2,6)pyridinophan-2,11-dione is obtained by the coupling reaction of 2,6-bis (bromomethyl)pyridine and 2,6-bis[2-isocyano-2-(tolylsulfonyl)ethyl]-4-tert-butylanisole in dimethylformamide (DMF) with an excess of sodium hydride, from which the corresponding syn-9-methoxy[3]metacyclo[3](2, 6)pyridinophane is synthesised via anti–syn-isomerisation during the Wolff–Kishner reduction in good yield.

3,3,17,17-Diethylenedioxyandrost-5-ene was obtained by ketalisation of androstenedione, which was oxidised with PDC and t-BuOOH to form 3,3,17,17-diethylene-dioxyandrost-5-ene-7-one. Stereoselective reduction of 3,3,17,17-diethylene-dioxyandrost-5-ene-7-one by NaBH₄ in the presence of CeCl₃.6H₂O gave 3,3,17,17-diethylenedioxy-7β-hydroxy-androst-5-ene, which was deprotected with p-toluenesulfonic acid to gave 3,3-ethylenedioxyandrost-5-ene-7β-hydroxy and androst-4,6-dien-3,17-dione. A series of androstenedione derivatives were obtained from 3,3-ethylenedioxyandrost-5-ene-7β-hydroxy by the esterification reaction. Their structures were confirmed by MS, ¹H NMR, ¹³C NMR and HRMS.

A rapid and efficient method for the synthesis of novel chenodeoxycholic acid thiosemicarbazone derivatives under solvent-free conditions using microwave irradiation is reported. Ten novel compounds have been synthesised in good yields. Their structures were elucidated by ¹H NMR, IR, ESI-MS spectra and elemental analysis. Preliminary results showed that some of these compounds possess inhibitory effects against S. typhimurium and E. coli.

The aza-Michael addition reaction of 4-aryl-7,7-dimethyl-1,2,3,4,5,6,7,8-octahydroquinazoline-2-one/thione-5-ones to α,β-ethylenic compounds in the presence of KF/Al₂O₃ furnishes N3-substituted quinazolinone derivatives. Those groups (NO₂, MeO) with larger steric hindrance at the o-position of the phenyl ring of quinazolinone have an apparent affect on the chemical selectivity thus giving the N1-subsituted products.

A new chemosensing ensemble that exhibits sensitive and selective recognition of pyrophosphate in 100% aqueous solution at physiological pH has been developed. The chemosensing ensemble was constructed by a dinuclear Zn(II) complex and eosin Y, the receptor–indicator pair is capable of selectively discriminating pyrophosphate from other common anions such as I^-, Cl^-, Br^-, F^-, CH₃COO^-, HSO₄^-, NO₃^-, H₂PO₄^-, HPO₄^2-, PO₄^3- and NCS^- in water at pH 7.4.

The N-benzoyl of α,β-dehydroamino acids that were obtained by condensation of N-benzoylglycine and an aldehyde, were esterified with an alcohol in high yield using cyclohexyl isocyanide to activate the carboxylic acid under neutral conditions.

A series of novel chiral bisimidazolium and chiral bis(benzimidazolium) dichlorides with different substituents were synthesised effectively from the corresponding N-substituted imidazoles or N-substituted benzimidazoles with chiral (S)-2,2'-bis(2-chloroethoxy)-1,1'-binaphthalene in solvent-free conditions at ambient pressure. This protocol features a short reaction time, good yields, an eco-friendly process and easily control and handling. These compounds were fully characterised by NMR, IR and elemental analysis, and their specific rotations were given.

A highly efficient manufacturing-scale process for the preparation of 2,6-dichloro-3-fluorobenzonitrile, utilising industrial by-product 2,6-dichloro-3-fluoroacetophenone as starting material, has been developed. The overall yield was 77%.

Acid-washed (pH 4 and pH 6) bentonite earth cleaves the tetrahydropyranyl ethers to the corresponding alcohols in good yield under mild conditions.

An improved method for the selective hydration of nitriles to amides employing N,N-disubstituted hydroxylamine is described leading to a reduction in reaction time and improved yield. Amides having electron-donating groups, which were not reported using the original method, were obtained in excellent yields. The amount of N,N-disubstituted hydroxylamine was reduced from three equivalents to one equivalent and the use of water as the reaction medium is environmentally friendly.

Ionic liquids were employed as a part of composite phase transfer catalyst to synthesise mandelic acid, and it is found that [bmim]PF₆ coupled with β-cyclodextrin is the most effective catalyst, which was also applicable to other reactions used to synthesise mandelic acid derivatives. Reaction conditions were optimized and the products were characterised by ¹H NMR and IR.

The Zn(II) complexes: [Zn(Hbimtz)₂Cl₂]·H₂O, [Zn₂(Hbimtz)₄Cl₄]·H₂O, and {[Zn₂(H₂O)₄(SO₄)₂(Hbimtz)₂]·(H₂O)_2.5}_n, where Hbimtz = 1-[(1H-benzimidazole-2-yl)methyl]-1,2,3,4-tetrazole, have been synthesised and their structures determined. The mononuclear complexes have four–coordinated Zn(II) centres with two benzimidazole N atoms from Hbimtz and two terminal Cl atoms, while the Zn(II) centre of the dinuclear complex is ligated by N atoms of Hbimtz and O atoms of sulfate and water molecules in distorted octahedral geometry. The thermal stability and luminescent properties of the three complexes are also discussed.

A novel N,N'-diethyl-4,4'-bipyridine copper complex, [Cu₂Cl₄][(C₂H₅)₂-4,4'-bipyridine] (1), has been obtained in situ through a solvothermal reaction and structurally characterised by X-ray diffraction. Complex 1 comprises discrete Cu₂Cl₄ moieties and (C₂H₅)₂-4,4'-bipyridine molecules interlinked via hydrogen bonding interactions to give a three-dimensional supramolecular open framework. Photoluminescent study shows that the complex exhibits an emission in the green region. Theoretical study reveals that the emission is attributed to the π → π^* charge-transfer interaction of the (C₂H₅)₂-4,4'-bipyridine moieties.