Phosphine-catalyzed [2 + 4] annulation of allenoates with thiazolone-derived alkenes has been achieved under mild conditions, giving biologically important 6,7-dihydro-5H-pyrano[2,3-d]thiazole derivatives in high to excellent yields. With the use of Kwon's phosphine as the chiral catalyst, optically active products were obtained in good yields with excellent enantioselectivities.

By the reaction of TBA(4)H(4)[γ-SiW(10)O(36)] (TBA = tetra-n-butylammonium) with AgOAc (OAc = acetate) using dimethylphenylsilane as a reductant in acetone, a unique polyoxometalate containing a discrete octahedrally shaped [Ag(6)](4+) cluster, TBA(8)[Ag(6)(γ-H(2)SiW(10)O(36))(2)]·5H(2)O, could be synthesized, and the molecular structure was determined.

The multicomponent reaction of 5-aminopyrazole derivatives with cyclic 1,3-dicarbonyl compounds and dimethylformamide dimethylacetal (DMFDMA) in DMF at 150 °C under controlled microwave heating afforded regioselectively 8,9-dihydropyrazolo[1,5-a]quinazolin-6(7H)-ones 6 rather than the corresponding dihydropyrazolo[5,1-b]quinazolin-8(5H)-ones 4.

Biologically active 3H-pyrrolo[2,3-c]quinolin-4(5H)-ones have been synthesized in an efficient and concise manner utilizing readily available 4-hydroxyquinolin-2(1H)-ones as the starting material. The key strategy relies on the construction of the pyrrole ring through the palladium catalyzed sequential cross-coupling reaction and cyclization process.

The evolution of heterocycles from hexaazaanthracene to tetraazapentacenes led to the discovery that syn aza-substituted polyazaacenes possess unusual zwitterionic structures. One of these, 5,7-diphenyl-5H,12H-quinoxalino[2,3-b]phenazine 4, first claimed in 1898 was fully characterized, including an X-ray crystal structure. These heteroacenes have a low calculated singlet-triplet gap and have u...

The ylides Ph3E-C6H6N2O3 (7, E = P (a), As (b), Sb (c)) have been prepared through the reaction of Ph3E and 5bromo-1,3-dimethyl-2,4,6(1H,3H,5H)-pyrimidinetrione (5-bromo-1,3-dimethylbarbituric acid) 6 in the presence of triethylamine. Their characterisation was performed by nuclear magnetic resonance (NMR), mass spectrometry (MS) and elemental analysis.

Coumarins appended to benzimidazole through pyrazole are designed and synthesized using microwave irradiation. These compounds were analyzed for phosphodiesterase (PDE) inhibition indirectly by motility pattern in human spermatozoa. Some of the synthesized compounds, namely, 5d, 5e, 5f, 5g, 5h, and 5k, have exhibited potent inhibitory activity on PDE.

The reaction of N,N’-persubstituted selenoacrylamides with alkyl bromoacetates gives rise to the formation of alkyl derivatives of N,N-disubstituted 2-aminoselenophene-5-carboxylates which can be transformed by saponification into corresponding 5-carboxylic acids. These compounds decompose by heating under formation of hitherto unknown N,N-disubstituted 2-amino-5H-selenophenes their spectral an...

The possible origin of luminescent properties of biodegradable photoluminescent polyesters (BPLPs) has been revealed by isolation and identification of luminescent agent from the hydrolyzate of BPLP. Elemental analysis, ESI-MS, (1)H, (13)C, 2D HSQC and COSY NMR spectra confirmed the chemical structure as 5-oxo-2,3-dihydro-5H-[1,3]thiazolo[3,2-a]pyridine-3,7-dicarboxylic acid (TPA).

The direct aldol reaction of γ-crotonolactone and various aromatic aldehydes is catalyzed by bifunctional aminothiourea and aminosquaramide organocatalysts to provide diastereomerically and enantiomerically enriched 5-substituted 2(5H) furanones (γ-butenolides). The reaction is a simple alternative to the classical vinylogous aldol reaction of silyloxy furans.