Journal of Chemical Research

The paper highlights the Michael addition reactions of 2-arylimino-3-aryl-thiazolidin-4-one 1 with acceptors like methyl acrylate and acrylonitrile to furnish the diadducts 5 and 8. Dieckmann condensation of 5 affords the spirocyclohexanone derivative. Also discussed is the interaction of 1 with 1,5-diarylpenta-1,4-dien-3-ones 9.

The electrophilic addition of bromine to 13-anti-bromo-endo-benzocyclobutenonorbornene 7 at −50 ± 5 °C has led in high yield to the formation of the rearranged dibromides 9, 10 and 11. In addition to this, bromination of exo isomer 8 results in formation of rearranged 9 and non rearranged product 10. However, high-temperature bromination of endo 7 and exo isomer 8 at 77 °C gave only non-rearranged products. The possible role of a substituent in rearrangements is discussed in these systems.

Reaction of VO(OPrⁱ)₃ with two equivalents of N-phenyldiethanolamine (PhDEAH₂) yields a homometallic complex [VO(PhDEA)(PhDEAH)] 1, which reacts with a number of metal alkoxides to afford heterobimetallic oxovanadium(V) complexes of the types [VO(PhDEA)₂{M(OR)_n-1}] [where PhDEA = C₆H₅N(CH₂CH₂O^–)₂], [M =: Al (n = 3, R = Prⁱ) 2; Al (n = 3, R = Bu^t) 3; Ti (n = 4, R = Prⁱ) 4; Zr (n = 4, R = Prⁱ) 5; Nb (n = 5, R = Prⁱ) 6; Ta (n = 5, R = Prⁱ) 7. The derivative [VO(PhDEA)(OSiPh₃)] 8 has been prepared by the equimolar interaction of [VO(PhDEA)(OPrⁱ)] with Ph₃SiOH. All of these complexes have been characterised by spectroscopic (IR; ¹H, ¹³C, ²⁷Al and ⁵¹V NMR) studies, elemental analyses, and molecular weight measurements. The derivative 2 has also been characterised by FAB mass spectral studies, which supports for its monomeric nature.

Reaction of the cyanoacetic hydrazide derivatives 1a–e with isothiocyanates gave the hydrazinocarboxamide and thioamide derivatives 2a–g and 1,2,4-triazole-3-thiones 3. Upon reacting 1b–d with ethyl bromoacetate followed by isothiocyanates; the 1,3-thiazole-5-carbohydrazides 5 were afforded. Cyclisation of products 1b–e with triethylorthoformate furnished the unexpected ethyl cyanoacetylhydrazonoformate 6; rather than the expected triazolethiones of type 7. A mechanism for the formation of product 6 was suggested and discussed. Upon heating product 6 with some arylamines in acetonitrile, the 5-aminotriazepin-7-ones 9 were afforded.

Pinacol coupling of aromatic aldehydes and ketones by TiCl₄–Mg–THF under ultrasound irradiation can lead to the corresponding pinacols in 20∼89% yields.

Piperazine as a new reagent for the condensation of aryl aldehydes and their bisulfite adducts with malonic acid are described which afford the corresponding cinnamic acids in excellent yields and short reaction times in the absence of solvents under microwave irradiation.

Aluminium amalgam – mediated reductive dimerisation of 3-methoxycarbonyl-4-oxo-4H-1-benzopyran produced two sets of diastereomeric bichromones coupled through 2,2′ and 2,4′- positions; the latter set of diastereomers underwent diastereoconvergent dehydration to produce Z-3,3′-dimethoxycabonyl-3H-2,4′-bi[1-benzopyran-2-ylidene]-4-one.

Hydrozirconation of terminal alkynes 1 gives (E)-alkenylzirconium complexes 3, which cross-couple with (E)-α-iodovinyltellurides 4 in the presence of [Pd(PPh₃)₄] catalyst to afford stereoselectively 1,3-dienyltellurides 5 in good yields.

A variety of thioacetal (2) are deprotected to parent carbonyl compounds (3) using 1-butyl-4-aza-1-azoniabicyclo[2.2.2] octane dichromate (BABOD) (1) in the presence of AlCl₃ in refluxing CH₃CN.

6-Alkylcarbamato-2,10-dibromodibenzo[d,g][1,3,6,2]dioxathiaphosphocin 6-oxides were prepared by cyclisation of 5,5′-dibromo-2,2′-dihydroxydiphenyl sulfide with dichlorophosphinyl carbamates/thiocarbamates, obtained by the addition of alcohols/thiols to dichloroisocyanatophosphine oxide, and characterised by IR, ¹H, ¹³C, ³¹P NMR and mass spectral studies.

3-(3-Methylbenzofuran-2-yl)-3-oxopropanenitrile (2), a versatile synthon, was prepared and utilised in the synthesis of several azoles and fused azolo-azine derivatives.

Acidic hydrolysis and acetylation of epoxidation products 11a/b of 1,4-diacetoxy-2-cycloheptene afforded unsymmetrical 1,2,3,4-tetraacetoxycycloheptane (12). OsO₄-cis-hydroxylation and acetylation of 1,4-diacetoxy-2-cycloheptene gave two symmetrical 1,2,3,4-tetraacetoxycycloheptanes (14/15). Deacetylation of 1,2,3,4-tetraacetoxy cycloheptanes gave cycloheptane-1,2,3,4-tetraols as cyclitol mimetics.

A series of amphiphilic N-(O,O-dihexadecyl)phosphorylamino acids were designed and synthesised, and the transmission FT–IR spectroscopic investigation of their Langmuir–Blodgett films (LB films) on CaF₂ substrates indicates the spontaneous polycondensation at the air/water interface before the deposition.

Two kinds of task-specific ionic liquids (Ils) composed of imidazolinium or pyridinium cations with a carboxy group and hydrogensulfate as counterion have been synthesised and their application in oxidation of olefins has been studied. The carbonyl compounds were obtained from the oxidation of chain olefins, and 1,2-cycloalkandiols were obtained from cycloalkenes in the novel oxidation systems which are easily manipulated. The products can be easily isolated from the reaction system and the ILs can readily be recovered and reused.

A new application of N-bromophthalimide for the facile oxidation of thiols to their corresponding symmetrical disulfides is described. A wide variety of thiols (aromatic, aliphatic and heterocyclic) were selectively oxidised to their corresponding disulfides with [NBPI] in a mixture of acetone and water under microwave irradiation in a microwave oven at a power output of 650W.

The nature of activation of methane on supported nickel catalyst has been investigated by means of temperature programmed surface reaction (TPSR), temperature programmed desorption (TPD), X-ray photoelectron energy spectroscopy (XPS) and pulse reaction and a synergetic mechanism of carbon dioxide reforming with methane is tentatively postulated. TPSR, TPD and XPS results indicate that carbidic C_α, carbonaceous Cβ and carbidic clusters C_γ surface carbon species formed by decomposition of methane show different surface mobility, thermal stability and reactivity. C_α and C_β species on the nickel surface are thermally unstable and can be rapidly converted into C_γ species upon increasing temperature. The carbidic carbon is a very active and important intermediate in carbon dioxide reforming with methane and the carbidic clusters C_γ species might be the precursor of the surface carbon deposition.

The highly reactive 1:1 adduct produced in the reaction between alkyl or aryl isocyanides and dialkyl acetylenedicarboxylates is trapped by N,N′-dimethylbarbituric acid to yield 4H-pyrano[2,3-d]pyrimidine derivatives.

Non-substituted phthalocyanines have been synthesised starting from phthalonitrile in various non-aqueous solvents in the presence of two different zeolites of the clinoptilolite type is studied. The zeolites are shown to be effective matrices for phthalonitrile cyclisation at relatively low temperatures (0–40°C).

Methyl long-chain alkenoates on treatment with chloramine-T [N-chloro-N-sodio-p-toluenesulfonamide] resulted in the formation of the corresponding aziridines in moderate yields. The N-substituted aziridine derivatives based on methyl undec-10-enoate (1), methyl (Z)-octadec-9-enoate (3) and methyl (9Z,12R)-12-hydroxyoctadec-9-enoate (5) have been synthesised under mild reaction conditions. The products were characterised using micro-analytical and spectral data.

Promoted by the samarium/samarium diiodide mixed reagent, the C–H insertion of phenyl acetylene via the dethiolation of N,N-disubstituted aromatic thioamides was successfully performed to afford 1,3-diaryl-3-aminopropynes in good yields.