Isocyanide-based consecutive Bargellini/Ugi reactions: an efficient method for the synthesis of pseudo-peptides containing three amide bonds.

Isocyanide-based consecutive Bargellini/Ugi multicomponent reactions as a combinatorial strategy have been developed for the synthesis of new class of pseudo-peptides. Via Bargellini reaction 3-carboxamido-isobutyric acids are prepared using acetone, chloroform, sodium hydroxide, and isocyanides. Then, using Ugi multicomponent reaction strategy, pseudo-peptides containing three amide bonds are synthesized using the Bargellini reaction product, aldehydes, amines, and isocyanides. This is an efficient and eco-friendly approach for easy access to wide variety of structurally diverse, drug-like pseudo-peptides from cheap and readily available precursors in high yields.

Transition-metal-free oxidative cyclization reaction of enynals to access pyrane-2-one derivatives.

A novel and efficient metal-free C-H functionalization of enynals is developed to synthesize α-pyrone derivatives via the formation of two C-O bonds. In this project, K2S2O8 has been introduced as an efficient oxygen source and C-H functionalization agent in regioselective oxidative cyclization reaction with a relatively broad substrate scope.

One-pot four-component synthesis of highly substituted [1,2,4]triazolo[1,5-a]pyrimidines.

A green one-pot four-component strategy has been developed for the synthesis of [1,2,4]triazolo[1,5-a]pyrimidine-6-carboxamide derivatives using an amine, 2,2,6-trimethyl-4H-1,3-dioxin-4-one, an aldehyde, and 3-amino-1,2,4-triazole in the presence of a catalytic amount of p-toluenesulfonic acid in water within 4-6 h.

1,5-Dichloro-4,8-dinitro-anthraquinone.

The ring skeleton of the title compound, C(14)H(4)Cl(2)N(2)O(6), is close to planar (r.m.s. deviation of the carbon atoms 0.091 Å); the nitro goups are twisted with respect to the mean plane of the ring system by 70.8 (1) and 86.7 (2)°. The crystal studied was found to be a merohedral twin, with a domain ratio of 0.61 (8):0.39 (8).

1,8-Dihydr-oxy-2,4,5,7-tetra-nitro-9,10-anthraquinone.

The ring system in the title compound, C(14)H(4)N(4)O(12), is essentially planar (r.m.s. deviation of the carbon atoms = 0.085 Å); the two hydr-oxy groups form intra-molecular hydrogen bonds to the same carbonyl O atom. The nitro groups are twisted with respect to the mean plane of the ring system by 74.3 (1) (1-nitro), 42.3 (3) (3-nitro), 45.7 (3) (6-nitro) and 66.9 (1)° (8-nitro).

1,5-Dicyano-anthraquinone.

The complete mol-ecule of the title compound, C(16)H(6)N(2)O(2), which is generated by a crystallographic inversion centre, is almost planar (r.m.s. deviation = 0.04 Å). In the crystal, adjacent mol-ecules are stacked along the a axis, with a shortest centroid-centroid separation of 3.826 (2) Å.

Fabrication of blue organic light-emitting diodes from novel uranium complexes: synthesis, characterization, and electroluminescence studies of uranium anthracene-9-carboxylate complexes.

In this study, three uranium(vi) complexes, [UO2(C15H9O2)2(CH3CH2OH)2]·2CH3CH2OH (1), [U2O4(C15H9O2)2(CH3O)2(CH3OH)2]·2CH3OH (2), and [U2O4(C15H9O2)4(CH3OH)2]·2H2O (3), were prepared by reacting anthracene-9-carboxylic acid with uranyl acetate dihydrate using various ligand to uranyl acetate ratios in different solvents. The infrared and UV-Vis spectra along with elemental and thermal analyses showed the formation of mono- and dinuclear anthracene-9-carboxylate complexes of uranium. A 1 to 3 molar ratio of uranyl acetate to anthracene-9-carboxylic acid in ethanol resulted in the formation of the mononuclear complex 1, whereas a 1 to 2 and 1 to 3 molar ratio of uranyl acetate to anthracene-9-carboxylic acid in methanol produced the dinuclear complexes 2 and 3, respectively. Single-crystal structure determinations of 1, 2 and 3 revealed hexagonal bipyramidal geometries for the mononuclear uranium complex of 1 and a pentagonal geometry for the dinuclear uranium complexes of 2 and 3. The single-crystal structures of complexes 2 and 3 showed π-π interactions in contrast to complex 1. The strong π-π interactions in complex 2 and 3 lead to an enhanced photoluminescence intensity in comparison with 1 without π-π interaction. The optical properties of the prepared complexes are associated with the ligand-induced resonant system. The fluorescent uranium complex 1 that showed a blue emission upon excitation at 270 nm was used for the fabrication of a blue organic light-emitting diode (BOLED), an industrially important OLED, using a simple solution-process fabrication method.

Aqua-chloridodimethyl-phenyltin(IV)-15-crown-5 (2/1).

The Sn(IV) atom in the title compound, 2[Sn(CH(3))(2)(C(6)H(5))Cl(H(2)O)]·C(10)H(20)O(5), exists in a trans-C(3)SnClO trigonal bipyramidal geometry in which the organo substituents occupy the equatorial sites. The coordinated water mol-ecule forms two hydrogen bonds to the 15-crown-5 mol-ecule, which is disordered about a center of inversion.

Metal-Organic Frameworks via Emissive Metal-Carboxylate Zwitterion Intermediates.

This month's cover is dedicated to the golden anniversary of Singapore by the collaborating groups of Wen-Hua Zhang of the IMRE, Singapore, and T. S. Andy Hor of the NUS, Singapore, and two more groups from Monash University, Malaysia, and Soochow University, P. R. China. In the cover picture the number "50" commemorates the 50th anniversary of Singapore, the Lion City. The photo on the top-right corner shows the modern skyline of Singapore. Underneath are the structures described in this article. Read the full text of the article at 10.1002/cplu.201500134.

Metal-Organic Frameworks via Emissive Metal-Carboxylate Zwitterion Intermediates.

Pyridinemethanol-carboxylate esters form octahedral complexes with Zn(NO3 )2 in aqueous DMF that subsequently undergo hydrolysis at elevated temperatures to form metal-carboxylate zwitterions. In situ deprotonation of the hydroxy group leads to thermally robust, neutral MOFs. This stepwise synthesis can be controlled by temperature and is made possible by the subtle difference in reactivity of the functional groups.