Journal of Chemical Research

An efficient route for the synthesis of polysubstituted pyrrole derivatives through a three-component intermolecular Wittig reaction is described. This simple fragment assembly strategy uses mild conditions and affords a broad range of polysubstituted pyrroles in moderate to good yield from simple and readily available starting materials.

A simple and efficient one-pot three-component approach was devised for the synthesis of spiro-oxindoles through the reaction of isatin derivatives, malononitrile and 1,3-dicarbonyl compounds in the presence of modified montmorillonite (Fe³⁺-mont.) under ultrasonic irradiation. The reaction furnished the desired products in excellent yields (85–95%) and short reaction times (2–7 min).

A convenient route for the synthesis of a third-generation epidermal growth factor receptor inhibitor, mereletinib (AZD9291) using starting materials that are commercially available has been achieved through reactions that are readily conducted under mild conditions. Importantly, a 5 g scale synthesis was also accomplished and this method could therefore be useful in the synthesis of similar drugs.

An efficient method is developed for the synthesis of 5-substituted 1H-tetrazoles through the [3 + 2] cycloaddition reaction of nitriles with sodium azide using silver(I) bis(trifluoromethanesulfonyl)imide (AgNTf₂) as a catalyst. This procedure provides mild reaction conditions, short reaction times and high yields.

A simple, one-pot procedure is described for the stereospecific preparation of β-chloro esters from the corresponding crowded epoxide.

5-Chloro-2, 3, 4-trifluorobenzoic acid, a key intermediate for preparing quinolone-3-carboxylic acid derivatives, was synthesised from the commercially available 2, 3, 4, 5-trifluorobenzoic acid in excellent yield by a reaction sequence involving nitration, selective reduction, diazotisation and chlorination.

The synthesis of tungsten carbide nanostructures on silicon substrates using hot filament chemical vapour deposition is described. The effect of substrate temperature and gas mixture on structural and morphological properties of the nanostructure was studied by X-ray diffraction (XRD), field emission scanning electron microscopy, atomic force microscopy (AFM), energy dispersive X-ray analysis (EDAX) and Raman spectroscopy. The XRD results show that different phases are more likely to grow due to increasing carbonisation by increasing the temperature. Also EDAX analyses confirm the presence of tungsten and carbon in structure. All Raman spectra indicate the occurrence of the amorphous carbon, characterised by two peaks, one related to carbon network and another which is due to disorder. From AFM images we can conclude that the grain size increased by increasing the temperature and this caused the increase in the roughness.

Bunte salts, easily prepared from odourless sodium thiosulfates and various alkyl and aryl halides, acted as thiol surrogates for preparation of disulfides in the presence of hydrogen peroxide and a Brønsted-acidic deep eutectic mixture. The reaction proceeded smoothly to give the corresponding disulfide products in moderate to good yields, leaving odourless sodium bisulfite and water as the by-products. Moreover, this catalytic system could be readily recovered and reused several times without significant loss in activity.

Concise and efficient total syntheses of bromotyrosine-derived metabolites aplysinellamides A and B, isolated from Australian marine sponge Aplysinella sp., have been accomplished in seven steps. A condensation between cinnamic acid and Boc-D-lysine methyl ester was applied to form the amide skeleton as a key step.

A series of novel urea derivatives containing the 1,2,3-thiadiazole moiety were synthesised using microwave-assisted condensation reactions of 4-methyl-1,2,3-thiadiazole-5-carbohydrazide with various substituted isocyanatobenzenes in acetonitrile. Their chemical structures were characterised by ¹H NMR, MS and elemental analysis. This method provides several advantages such as high yields, facile work-up and is environmentally friendly.

3,3′-Dihydroxy-6,6′(or 7,7′)-dimethyl-3,3′-dipropyl-[2,2′-bi-1H-indenylidene]-1,1′-dione was found to undergo photochromism in a single crystalline phase from yellow to red. The structure of the compound was confirmed by X-ray crystallography analysis. Results showed that the compound contains a pair of isomers, 3,3′-dihydroxy-6,6′-dimethyl-3,3′-dipropyl-[2,2′-bi-1H-indenylidene]-1,1′-dione and 3,3′-dihydroxy-7,7′-dimethyl-3,3′-dipropyl-[2,2′-bi-1H-indenylidene]-1,1′-dione. A plausible reaction mechanism was proposed.

Three chiral manganese(III) Schiff-base complexes [Mn(R,R-Salcy)(CH₃OH)(N₃)], [Mn(S,S-Salcy)(DMF)(N₃)] (both monomers by X-structure determination) and the trinuclear complex (X-ray structure) {[Mn(R,R-Salcy)(H₂O)]₂[μ-Ni(CN)₄]}·3CH₃OH·H₂O [Salcy = N,N′-(1,2-cyclohexanediylethylene)bis(salicylideneiminato)dianion)] have been synthesised. The trimeric complex shows weak antiferromagnetic interactions between the adjacent Mn(III) ions.

Novel di-tert-butylated polycyclic aromatic hydrocarbons (PAHs) with [4] helicene components were prepared through an oxidative photocyclisation reaction. The structural properties of the PAHs were evaluated with ¹H NMR and X-ray crystallography. It was detected that the PAHs have highly twisted π-conjugated systems and a deep fjord region. Although they are not planar, these PAHs can readily form dimers in solutions and undergo staggered one-dimensional array columnar crystal packing by intermolecular π–π interactions.

Novel cis-N-acyl-2,3-dimethyl-3,4-2H-1,4-benzoxazine derivatives were synthesised by acylation of 2,3-dimethyl-3,4-dihydro-2H-1,4-benzoxazine derivatives, which were prepared via the reduction and cyclisation of 3-(o-nitrophenoxy)butan-2-one. The configuration was determined by X-ray crystallography.

One-pot synthesis of new dihydropyrimidinone and tetrahydro-2-thioxopyrimidinone derivatives by a three-component reaction between appropriate amines, phenyl isocyanate or phenyl isothiocyanate with ethyl bromopyruvate in DMF under ultrasound irradiation without using bases and catalysts.

The mono-azo dye, Orange-II (acid orange 7), is mainly used to dye materials like textiles, paper, leather and cosmetics. It is important to understand the kinetic and mechanistic aspects of the oxidative decolourisation of Orange-II dye. A simple, efficient and cost-effective oxidation method is developed for the reaction. A detailed kinetic study of the oxidative decolourisation of orange-II dye with chloramine-T (CAT) in alkaline medium at 308 K has been carried out spectrophotometrically at 486 nm. The reaction shows a first-order dependence of rate both on [CAT]_o and [Orange-II]_o and an inverse-fractional- order on [OH⁻]. The reaction was studied at different temperatures and the thermodynamic parameters have been evaluated. The reaction was subjected to change in (i) ionic strength, (ii) p-toluenesulfonamide and (iii) chloride ions, and the effects of these on the reaction rate were determined. Oxidation products of Orange-II were characterised as 1,2-naphthaquinone and benzenesulfonic acid by GC-MS analysis. The observed kinetic results have been explained by a general mechanism to understand the elementary pathways of this redox system. The relevant kinetic modelling has been worked out.

Calcitriol analogues which contained an oxime in the side chain were synthesised in five steps from an intermediate 22-nor Ketone. The key intermediate enones were synthesised by the Wittig–Horner olefination and Wittig olefination respectively. Reduction, oximation, photoisomerisation and deprotection gave the target compounds with the oxime at C-24.