Letters in Organic Chemistry - Volume 9, Issue 10, 2012

N-Tosyl-3-nitroindole reacts with moderate and strong nucleophilic dienes in a polar Diels-Alder reaction using protic ionic liquid (PIL) [HMIM][BF4] as reaction media. In the cases in which the diene has oxygenated substituents, the PIL favors the aromatization of the formal [4+2] cycloadducts. Although the presence of the PIL in the reactions of Ntosyl- 3-nitroindole as electrophile shows a clear tendency to the aromatization of t Read More

The synthesis of 5,5-dimethyl-1,3-bis(trimethylsilyl)cyclohexa-1,3-diene: a novel cyclic 1,3-dianionic synthon is reported by the Wurtz-Fittig coupling reaction of 1,3-dichloro-5,5-dimethylcyclohexa-1,3-diene with metallic sodium and chlorotrimethylsilane in anhydrous ether solvent. The compound on further Diels-Alder [π4s+π2s] cycloaddition with five N-substituted maleimides gave five novel cycloadducts: the N-substituted 11,11- Read More

The novel metacyclophanes with chalcone moieties were synthesized by Claisen-Schmidt condensation. These α,β-unsaturated ketones were photoisomerized from the all-trans configuration to the partial trans configuration by 365 nm light irradiation, and then, these cis photoisomers were thermally reversed

In this paper, an efficient synthesis of the two attractive fused thiophenes: [7]helicene (1) and double helicene (2) bearing chiral chains was developed via multi-step moisture sensitive reactions in ca. 10.5 % and ca. 6.0 % isolated yields, respectively, with dithieno[2,3-b:3',2'-d]thiophene (7) as a starting material. However, 1 and 2 showed no optical rotations due to the too weak contribution from chiral induction of the chi Read More

NiO-SnO2 composite nano-powder has been synthesized with an average size of 25 nm. The structural and compositional analysis of the prepared catalyst has been carried out by using XRD, XRF, and TEM. The prepared nanocomposite has been evaluated for its catalytic activity in the three-component reactions of aldehydes, amides / urea and 2- naphthol at 100 °C. The reaction results in the synthesis of a variety of 1-amido Read More

Syntheses of some novel dichromophoric cyanine dyes based on 2-aminobenzothiazoles have been reported. Their highly extended conjugated systems are in symmetrical and unsymmetrical structures, both of which are divided into two electron-rich and electron-poor series. The sixteen synthesized compounds absorb visible light in the region of 462-523 nm in ethanol in deep orange, red and purple color with high molar Read More

The reaction of 1,4-dihydro-4-oxo-1,8-naphthyridine-3-carbohydrazide (4) with substituted phenyl isothiocyanates (5) in ethanol under reflux for 30 min gave thiosemicarbazide derivatives 6, which on cyclization in 2N NaOH under refluxing conditions for 1h resulted in 3-(5-mercapto-4-phenyl-4H-1,2,4-triazol-3-yl)-1,8-naphthyridin-4(1H)-one (7). Alternatively, 7 could also be prepared from 4 through intermediacy of 8, i.e. 4 → 8 → 7 Read More

We have developed a new combination of catalyst system for the synthesis of N-(p-benzoylaminoaryl)-N'-Boc piperazines under microwave conditions (Biotage, 300 Watt) in the presence of sodium tert-butoxide and in DMF. The catalyst and ligand used are Tris (dibenzylideneacetone) dipalladium(0) and 2-Dicyclohexylphosphino-2'-(N,Ndimethylamino) biphenyl (Dave Phos) respectively, the desired N-(p-benzoylaminoary Read More

An environmentally benign Biginelli protocol for the synthesis of substituted 3, 4-dihydropyrimidin-2(1H)- ones using Fe+3-montmorillonite K-10 as a green catalyst in short reaction time and high yield has been achieved.

A combination of CuBr and hematoxylin was found to be a mild, efficient and environmentally benign catalyst system for S-arylation of thiols with aryl halides in DMF-H2O. A variety of aryl sulfides are synthesized from moderate to good yields, under relatively mild reaction conditions with good chemoselectivity and functional group tolerance.

4-hydroxyquinolinones 7 were applied as 1,3-dinucleophiles in the reaction with Baylis-Hillman adduct acetates 6 to synthesize, in high yields of 75-92%, novel 2H-pyrano[3,2-c]quinoline-2,5(6H)-diones which are present in a number of biologically active compounds. The reaction was carried out under different conditions to achieve the optimum ones. The results indicated that acetonitrile as solvent and K2CO3 as base, under refl Read More

An updated and practical approach to the synthesis of dithymoquinone via one-step photoirradiation of thymoquinone (2-methyl-5-isopropyl-1,4-benzoquinone) is described. Synthesis resulted in a 55 % yield of one structural isomer (trans-anti derivative), as confirmed by HPLC, NMR spectroscopy and first ever single-crystal X-ray diffraction analyses.