Journal of Chemical Research

The ozonolysis of terpenoids is described and the origins of some by-products are discussed.

Palladium-catalysed competitive three-component C–H functionalisation reactions and cascade coupling ring-closing reactions of quinones with iodophenols in dihaloalkanes are described. During initial attempts to conduct C–H functionalisation reactions of quinones with iodophenols in dihaloalkanes, surprisingly a three-component C–H functionalisation reaction was discovered. Furthermore, as the reaction of chloroquinones with iodophenols was in progress, another surprising cascade coupling with ring closure was achieved. This provided an efficient single-step synthesis of naphtho[2,3-b]benzofuran-6,11-diones.

Without the need of any protecting groups, aryl halides bearing acidic amides were coupled with several Knochel-type organozinc reagents by using Pd(OAc)₂ as catalyst and 2-dicyclohexylphosphino-2’,6'-dimethoxy biphenyl (S-Phos) as ligand. The reactions were carried out on a large scale (30 mmol), furnishing the desired coupling products smoothly in excellent yields (70–98%).

An efficient protocol for the synthesis of novel glycosyl-containing 1,2,4-triazolo[3,4-b][1,3,4]thiadiazole derivatives starting from the commercially available D-glucosamine hydrochloride is described by reaction of glycosyl isothiocyanate with various aminotriazoles in DMF. Glycosyl isothiocyanate is an important intermediate and synthetic methods are discussed. The acetylcholinesterase inhibitory activity of these compounds was tested by Ellman's method. It was found that most compounds exhibited over 90% inhibition and they were subsequently evaluated for their IC₅₀ values.

Oxidative α-cyanation of tertiary amines was achieved by using an MCM-41-immobilised N-alkylethylenediamine ruthenium(III) complex (MCM-41-2N-RuCl₃) as catalyst in MeOH at 60 °C in the presence of H₂O₂ as oxidant and NaCN in acetic acid as a cyanide source to afford the corresponding α-aminonitriles in good yields. The new heterogeneous ruthenium catalyst can easily be prepared by a simple two-step procedure from commercially readily available and inexpensive reagents. It can be recovered by filtration of the reaction solution and reused at least 7 times without significant loss of activity.

An efficient one-pot synthesis of 1-(4-bromophenyl)-1H-tetrazol-5-amine was performed using 4-bromoaniline as the starting material. A novel and widely applicable amidation procedure was then employed, whereby 1-(4-bromophenyl)-1H-tetrazol-5-amine was acylated with different acyl chlorides in the presence of lithium bis(trimethylsilyl)amide as catalyst, for the high-yield synthesis of [1-(4-bromophenyl)-1H-tetrazol-5-yl]amide derivatives.

A novel zinc complex [Zn₃(2,2′-bi-1H-imidazole)₂(1H-biimidazole)₂(SO₄)₂] _n has been synthesised through a solvothermal reaction and structurally characterised by single-crystal X-ray diffraction. It has a one-dimensional chain-like structure with both tetrahedral and square pyramidal zinc atoms. A three-dimensional supramolecular framework is constructed through hydrogen-bonding interactions. Photoluminescence shows that the complex displays an emission in the blue region of the light spectrum that time-dependent density functional theory calculations reveal can be attributed to ligand-to-ligand charge transfer. Solid-state diffuse reflectance measurements show the existence of a narrow optical band gap of 2.08 eV.

A metal-free, base-promoted facile synthesis of phenol derivatives utilising diaryliodonium salts as the aryl source and benzaldoxime as the hydroxide surrogate has been developed. The reaction is fast and shows good substrate compatibility, giving the corresponding products in good to excellent yields. A gram-scale synthesis of phenols utilising this protocol has also been achieved.

The incubations of androst-4-ene-3,17-dione with Aspergillus candidus MRC 200634, Aspergillus tamarii MRC 72400, Aspergillus wentii MRC 200316 and Mucor hiemalis MRC 70325 for 5 days are reported. A. candidus MRC 200634 mainly hydroxylated androst-4-ene-3,17-dione at C-11α, C-15α and C-15β whilst A. wentii MRC 200316 hydroxylated it mainly at C-6β. A. tamarii MRC 72400 showed predominately a Baeyer–Villiger monooxygenase activity. M. hiemalis MRC 70325 hydroxylated the substrate at C-14α and reduced most of it at C-17.

A new series of 7-trifluoromethyl-2-pyridylquinazolin-4(3H)-one-based acyl thiourea derivatives has been generated and tested for their cytotoxicity towards human ovarian cancer (SK-OV-3), cervical cancer (HeLa), renal cancer (Caki-2) cell lines, as well as noncancerous a human umbilical vein endothelial cell (HUVEC) line. The new thiourea derivatives were found to be promisingly cytotoxic towards the cancerous cell lines. Changing the substituent at the thiourea linkage led to variations in the cytotoxic potential of the resultant derivatives towards specific cell lines. Molecules with fluorine functionality and multiple pyridyl moieties showed encouraging anticancer effects and could be used as a platform for the design of further chemotherapeutic agents. The proposed structures of the products were ascertained through FTIR, mass, ¹H NMR and ¹³C NMR spectra and elemental analyses.

An efficient pseudo four-component reaction between substituted 2-hydroxybenzaldehydes, ammonium acetate and different dialkyl but-2-ynedioates for the preparation of (2E)-2-(6H,12H-6,12-epiminodibenzo[b,f][1,5]dioxocin-13-yl)but-2-enedioates in moderate to good yields (60–83%) was developed. This method uses a variety of cheap and readily available reactants and a wide range of substrates. The structure of a typical product was confirmed by X-ray crystallography.

The 1,3-dipolar cycloaddition of nitrilimine, generated in situ from N′-phenylbenzohydrazonoyl chloride and triethylamine, to 7-arylmethylidene-6,7-dihydroindolizin-8(5H)-one afforded novel 4′-aryl-2′,5′-diphenyl-2′,4′,5,6-tetrahydro-8H-spiro(indolazine-7,3′-pyrazol)-8-ones in moderate yields. The structures of all the products were characterised thoroughly by NMR, infrared spectroscopy and HRMS. The structure and stereochemistry was confirmed by X-ray diffraction analysis.

A one-pot, efficient, synthesis of six novel trans-spirocyclopropane-indanedione derivatives with high stereoselectivity has been achieved via the reaction of acetopyridinium chloride with 1,3-indandione and an araldehyde in the presence of triethylamine in acetonitrile under reflux conditions. The attractive features of the method are excellent yields and high purity, short reaction times, and easy work-up.

2-Cyano-3-nitroporphyrin derivatives were synthesised by the reaction of 2-nitroporphyrin with trimethylsilyl cyanide in the presence of tetrabutylammonium fluoride with moderate yields. The reaction took place regioselectively on the 3-position carbon of the porphyrins, which was confirmed by X-ray analysis.