Journal of Chemical Research

A novel one-step procedure for the synthesis of 2-substituted-isoindoles and 1-aryl-2-substituted-isoindoles is described. The procedure is based on the reaction of 2-(bromomethyl)benzaldehyde or 2-(bromomethyl)benzophen-one derivatives with primary aromatic or aliphatic amines. Reactions of 1,2-diarylisoindoles with N-phenylmaleimide were studied. Refluxing the reactants in i-PrOH in the presence of triethylamine leads to the formation of Diels–Alder endo-adducts; whilst refluxing in AcOH in the presence of AcONa affords Michael adducts. The structure of the latter was confirmed by X-ray diffraction.

A one-dimensional Cd(II) complex [Cd(3,4′-bpt)₂(H₂O)₂]·H₂O (1) (3,4′-Hbpt = 1H-3-(3-pyridyl)-5-(4-pyridyl)-1,2,4-triazole) has been synthesised and characterised using single crystal X-ray diffraction, IR and elemental analysis. In [Cd(3,4′-bpt)₂(H₂O)₂]·H₂O, two types of 2₁ helical chain were formed by the 3,4′-bpt spacers bridging the Cd(II) centres along the crystallographic a axis. These two helices were both in an orderly arrangement with the Cd atoms functioning as hinges to form the one-dimensional ordered helical array. The thermal stability and luminescent properties of the title complex have been briefly investigated.

Multicomponent condensation reactions of aldehydes, 2-naphthol and methyl/benzyl carbamate have been done by using magnesium 2,2,2-trifluoroacetate [Mg(OOCCF₃)₂] as an efficient catalyst. This methodology results in the synthesis of a variety of methyl (2-hydroxynaphthalen-1-yl)(aryl)methyl/benzylcarbamate derivatives in high yields. Despite their importance from pharmacological and synthetic points of view, comparatively few methods for the preparation of 1-carbamatoalkyl 2-naphthol derivatives have been reported via multicomponent reactions of aldehydes, 2-naphthol and carbamate using acidic catalysts. Magnesium 2,2,2-trifluoroacetate [Mg(OOCCF3)2] has been prepared from the reaction of trifluoroacetic acid and magnesium chloride. The prepared catalyst has been characterised through a powder X-ray diffraction pattern.

A novel dansyl-based fluorescent probe has been synthesised. Its structure was confirmed by single crystal X-ray diffraction, and its fluorescent property was also investigated.

The N-monoalkylation of 2- or 3-aminopyridines by a carboxylic acid and sodium borohydride afforded the corresponding alkylaminopyridine under mild conditions in good yields. N-Alkylaminopyridines are important intermediate for preparing N-containing heterocycles, such as “flytrap” aminopyridinium-based anion hosts and pharmaceuticals.

A microwave-assisted Claisen rearrangement/Diels–Alder cascade reaction was used to synthesise caged Garcinia natural products and analogues containing the unique 4-oxa-tricyclo[4.3.1.0^3,7]decan-2-one scaffold from xanthone-based and chromone-based substrates. Forbesione and cluvenone as well as two new and six known caged analogues were obtained. Compared with the traditional thermal method, the reaction time was reduced dramatically and the yield was greatly improved under microwave irradiation. In addition, the regioselectivity observed in the cascade reaction has also been rationalised. Garcinia have long been used in folk medicines for their healing, antibacterial, and cytotoxic activities.

Triethylammonium hydrogen sulfate [Et₃NH][HSO₄]) has been used as an efficient acidic ionic liquid catalyst for the preparation of 1,5-diaryl-3-(arylamino)-1H-pyrrol-2(5H)-ones at room temperature. The present methodology offers the advantages of good yields, a simple procedure, shorter reaction times and mild condition. The products were purified without resorting to chromatography.

(Z)-α,β-Unsaturated esters can be stereoselectively synthesised in one pot under mild conditions and in good yields, by the hydrostannylation of alkynyl esters followed by Stille cross-coupling with aryl iodides.

Celiprolol hydrochloride, a β-blocker drug, has been synthesised from 4-chloronitrobenzene. The route involved hydrolysis of the chloride and acetylation of the phenol, reduction of the nitro group, and acylation of theamine. This was followed by Fries rearrangement of the acetyl group, Williamson etherification with epichlorohydrin, followed by opening of the epoxide ring and salt formation. The overall yield of celipropol was 39.1% on the basis of 4-chloronitrobenzene. The Fries rearrangement was substantially improved. The process is suitable for industrial application because of its convenient and environmentally friendly reaction conditions.

Two polymorphs of (3-nitro-4-bromophenyl)acetic acid, were prepared as single crystals through hydrothermal reaction and were structurally characterised using single-crystal X-ray diffraction. Both polymorphs crystallise in the monoclinic space group P2₁/c, but their cell parameters are obviously different. Hydrogen-bonding interactions has a crucial role in assembling two small molecules into dipolymer in the two polymorphs. The arrangements of the dipolymers in phase A and B are remarkably different for the molecular orientation and interatomic distances according to their strong hydrogen bonds and π…π stacking interactions.

The introduction of methoxy groups into the 3- and 5-positions of 4-methoxybenzoyl chloride leads to a reduction in specific rates of solvolysis. An extended Grunwald–Winstein equation correlation for the specific rates of solvolysis of 3,4,5-trimethoxybenzoyl chloride gives sensitivities towards changes in solvent nucleophilicity (/ value) of 0.29 and towards changes in solvent ionising power (m value) of 0.54. The low m value allows specific rates to be determined in highly ionising fluoroalcohol-H₂O mixtures. A parallel correlation of the specific rates of solvolysis of 2,4,6-trichlorobenzoyl chloride reveals that solvolyses in 100% and 90% ethanol or methanol do not appreciably follow the ionisation pathway indicated for solvolyses in the other solvents and it is proposed that, despite the two ortho-substituents, the addition–elimination pathway has become dominant.

The direct synthesis of dimethyl carbonate (DMC) and propylene glycol from propylene oxide, CO₂ and methanol has been studied with potassium carbonate as catalyst. This is the first time that K₂CO₃ which is readily available has been used as a catalyst. It is quite simple and cheap to use. This route may be an effective way of producing DMC on the large-scale. DMC is used in polycarbonate synthesis, polyurethane synthesis, carbonylating reagents, alkylating reagents, polar solvents, octane boosters in gasoline, carbon-particle reducing agents for diesel engines It is a safe and environmentally benign alternative for phosgene in some reactions.

A mild and facile synthetic method of cyclic imides is presented. These compounds are widely used in the synthesis of novel medical, polymeric, photonic and electronic materials. Compared with traditional syntheses, the method reported has several advantages including mild conditions, simplified work-up and low cost.

A sesquiterpene antibiotic was isolated from the dried fruiting body of Dictyophora indusiata (Vent: Pers.) Fischer by solvent extraction and column chromatography and identified as albaflavenone by FTIR, GC-MS, HR-FIMS and NMR spectra. The content of albaflavenone in the dried fruiting body of Dictyophora indusiata (Vent: Pers.) Fischer (the content of water was 15.63%) was quantified by GC through an external standard method to be about 0.0063%. The compound isolated has an earthy, camphor-like odour.

Protonation of the reactive intermediates produced in the reaction between alkyl isocyanides and dialkyl acetylenedicarboxylates by carboxylic acids leads to vinylnitrilium cations which then undergo nucleophilic addition of the conjugate bases of the carboxylic acids. This intermediate rearranges to produce dialkyl (E)2-{[(aryl)acetyl(alkyl-amino)]carbonyl}-2-butenedioate derivatives.

A new cycloartane triterpenoid has been isolated from an EtOH extract of the stigma of Zea mays L. and shown to be cycloart-24-ene-2α, 3β-diol based on extensive spectroscopic analysis, including IR, NMR, and MS. The cytotoxic activity of this compound against BEL-7402, HL-60, PC3, and HeLa cell lines is described.

Nanostructured SiO₂–H₂SO)₄ has been prepared and shown to efficiently catalyse the one-pot, three-component reaction of an aromatic aldehyde, malononitrile and a cyclic 1,3-diketone at reflux, to afford the corresponding 4H-chromene derivative in high yield. 4H-Chromene derivatives are important pharmacological agents exhibiting spasmolytic, diuretic, anticoagulant, anticancer, and antianaphylactic activities.

A convenient synthesis of 5, 8-O-dimethylshikonin and the 6-isomer of 5,8-O-dimethylshikonin was developed in 81.8% total yield from shikonin. (R)-4-Methyl-1-(1,4,5,8-tetramethoxynaphthalen-2-yl)pent-3-en-1-ol was prepared in a one-pot two-step approach and then oxidised with ceric ammonium nitrate. This is simpler and the overall yield is higher than previous methods. The reaction conditions are milder and more environmentally friendly to environment, avoiding the use of the toxic and expensive reagents methyl iodide and chloromethyl ether and are more applicable to large-scale preparation. This is important because shikonin and its closely related derivatives have attracted much attention in view of their antitumor activities.

Organic compounds containing the thiazolinone ring are of increasing interest due to their bactericidal, pesticidal, anticonvulsant, antiinflammatory, antithyroidal and antimicrobial activities. A rapid microwave-assisted synthesis thiazolinone derivatives is described. The 3-(1H-benzo[d]imidazol-2-yl)-2-substituted phenyl thiazolidin-4-one were identified by IR, ¹H NMR, elemental analyses. The target compounds were performed in a shorter reaction time compared to conventional heating methods.