A new natural product named longanlactone was isolated from Dimocarpus longan Lour. seeds. Its structure was determined as 3-(2-acetyl-1H--pyrrol-1-yl)-5-(prop-2-yn-1-yl)dihydrofuran-2(3H)-one by spectroscopic methods and HRESIMS.

In the title compound, C(18)H(14)N(2)O(3), one of the phenyl rings is almost coplanar with the pyrrole ring [dihedral angle = 2.56 (14)°], whereas the other one is tilted by 63.01 (6)° with respect to the pyrrole ring. Since the NH group is shielded from possible acceptors, this group is not involved in hydrogen bonding.

An efficient synthesis of 1,3-diaryl-4-halo-1H-pyrazoles was achieved. The synthesis involves the [3 + 2] dipolar cycloaddition of 3-arylsydnones and 2-aryl-1,1-dihalo-1-alkenes. The process proceeds smoothly in moderate to excellent yields. 1,3-Diaryl-4-halo-1H-pyrazoles are found to be important intermediates that can easily be converted into 1,2,5-triaryl-substituted pyrazoles via Pd-catalyz...

The reaction of dibenzoylacetylene with 4-alkylaminocoumarins in THF/H2O (50:50) lead to 4-(alkylamino)-3-(1,4-dioxo-1,4-diphenylbut-2-en-2-yl)-2H-chromen-2-one derivatives in good yields. When the reaction carried-out in DMSO the cyclized products 2-hydroxy-1-alkyl-3-(2-oxo-2-phenylethylidene)-2-phenyl-2,3-dihydrochromeno [4,3-b] pyrrol-4(1H)-ones were formed in good yields.

The rearrangement of 4-methyl-3,5-diaryl-4H-1,2,4-triazoles to the corresponding 1-methyl-3,5-diaryl-1H-1,2,4-triazoles showed regioselectivity comparable to that observed for the alkylation of 3,5-diaryl-1H-1,2,4-triazoles. This lends support to a proposed mechanism for the rearrangement that involves consecutive nucleophilic displacements steps.

For the first time, a catalytic asymmetric Henry reaction of 1H-pyrrole-2,3-diones was achieved with a chiral bifunctional amine-thiourea as a catalyst possessing multiple hydrogen-bond donors. With this developed method, a range of 3-hydroxy-3-nitromethyl-1H-pyrrol-2(3H)-ones bearing quaternary stereocenters were obtained in acceptable yield (up to 75%) and enantioselectivity (up to 73% ee).