Coordination compounds with 4-aminopyridine. An unusual in situ formation of a bridging formato compound. The structure of catena-poly[bis(4-amino-pyridine)(formato-O)copper(II)-μ-formato(O,O′)]

Applications of alkyl orthoesters as valuable substrates in organic transformations, focusing on reaction media

In this review we focus on applications of alkyl orthoesters as valuable and efficient substrates to perform various classes of two-component and multi-component organic reactions. The article has classified them according to two aspects, which are: (i) a focus on the reaction medium (solvent-free conditions, aqueous media, and organic solvents); and (ii) an examination of product structures. Reaction accomplishment under solvent-free conditions is an eco-friendly process with the absence of volatile toxic solvents, which puts it in line with green chemistry goals. Water is an interesting choice in organic transformations due to its inexpensiveness and safety. The authors hope their assessment will help chemists to attain new approaches for utilizing alkyl orthoesters in various organic synthetic methods. The review covers the corresponding literature up to the beginning of 2020.

2-Chloro-pyrimidin-4-amine

In the title pyrimidine derivative, C(4)H(4)ClN(3), the 2-chloro and 4-amino substituents almost lie in the mean plane of the pyrimidine ring, with deviations of 0.003 (1) Å for the Cl atom, and 0.020 (1) Å for the N atom. In the crystal, molecules are linked via pairs of N-H⋯N hydrogen bonds, forming inversion dimers. These dimers are further linked via N-H⋯N hydrogen bonds, forming an undulating two-dimensional network lying parallel to (100).

Metal Complexes of 3-Thiophene Carboxamides Containing a Pyridine Ring

Complexes of Zn(II), Cu(II) and Co(II) with either N-(2-methylpyridyl)-3-thienyl-alkyl-carboxamide or N-(2-pyridyl)-3-thienylalkyl-carboxamide groups have been prepared and characterized. Crystal structures of ten new complexes are reported and discussed. N-(2-Methylpyridyl)-3-thienyl-alkyl-carboxamide exhibits both uni- and bidentate behavior. With all ligands, bidentate complexation is through the carbonyl oxygen and pyridine nitrogen atoms (O, N) and the amide nitrogen atom remains protonated. The electrochemical behavior and the infrared spectra of selected complexes are discussed.