Formate and CO2 Enable Reductive Carboxylation of Imines: Synthesis of Unnatural α-Amino Acids.

Herein, a photocatalytic umpolung strategy for reductive carboxylation of imines for the synthesis of α-amino acids was disclosed. Carbon dioxide radical anion (CO2•-) generated from formate is the key single electron reductant in the reactions. An unprecedentedly broad substrate scope of imines with excellent reaction yields was obtained with carbon dioxide (CO2) and formate salt as carbon sources.

Dinuclear cobalt and nickel complexes of a mercaptoacetic acid substituted 1,2,4-triazole ligand: syntheses, structures and urease inhibitory studies.

Because of its versatile coordination modes and strong coordination ability, the mercaptoacetic acid substituted 1,2,4-triazole 2-{[5-(pyridin-2-yl)-4H-1,2,4-triazol-3-yl]sulfanyl}acetic acid (H2L) was synthesized and characterized. Treatment of H2L with cobalt and nickel acetate afforded the dinuclear complexes {µ-3-[(carboxylatomethyl)sulfanyl]-5-(pyridin-2-yl)-4H-1,2,4-triazol-4-ido-κ2N1,N5:N2,O}bis[aqua(methanol-κO)cobalt(II)] methanol disolvate, [Co2(C9H6N4O2S)2(CH3OH)2(H2O)2]·2CH3OH (1), and {µ-3-[(carboxylatomethyl)sulfanyl]-5-(pyridin-2-yl)-4H-1,2,4-triazol-4-ido-κ2N1,N5:N2,O}bis[diaquanickel(II)] methanol disolvate dihydrate, [Ni2(C9H6N4O2S)2(H2O)4]·2CH3OH·2H2O (2), respectively. Complex 1 crystallized in the monoclinic space group P21/c, while 2 crystallized in the tetragonal space group I41/a. Single-crystal X-ray diffraction studies revealed that H2L is doubly deprotonated and acts as a tetradentate bridging ligand in complexes 1 and 2. For both of the obtained complexes, extensive hydrogen-bond interactions contribute to the formation of their three-dimensional supermolecular structures. Hirshfeld surface analysis was used to illustrate the intermolecular interactions. Additionally, the urease inhibitory activities of 1, 2 and H2L were investigated against jack bean urease, where the two complexes revealed strong urease inhibition activities.

The genus Scaptodrosophila Duda part II: the coracina species group from East Asia, with morphological and molecular evidence (Diptera, Drosophilidae).

Eight new species of the Scaptodrosophila coracina species group are described from China: S. fuscilimbasp. n., S. fusciventriculasp. n., S. helvpectasp. n., S. longispinatasp. n., S. nigrolimbatasp. n., S. trivittatasp. n., S. ventriobscuratasp. n., and S. zebrinasp. n. One known species S. coracina (Kikkawa & Peng) is redescribed. A key to all the examined species in the coracina group is provided. Species delimitations have been improved by integrating the DNA sequences with morphological information. The intra- and interspecific pairwise p-distances (proportional distance) are summarized. Some nucleotide sites with fixed status in the alignment of the COI sequences (662 nucleotide sites in length) are used as "pure" molecular diagnostic characters to delineate species in the coracina group.

The genus Scaptodrosophila Duda part I: the brunnea species group from the Oriental Region, with morphological and molecular evidence (Diptera, Drosophilidae).

Seven new species of the Scaptodrosophila brunnea species group are described from east Asia: S. maculatasp. n., S. melanogastersp. n., S. nigricostatasp. n., S. nigripectasp. n., S. obscuratasp. n., S. protenipenissp. n. and S. rhinasp. n. Three known species, S. parabrunnea (Tsacas & Chassagnard), S. pressobrunnea (Tsacas & Chassagnard) and S. scutellimargo (Duda) are redescribed. A key to all the examined species in the brunnea group is provided. Species delimitations have been improved by integrating the DNA sequences with morphological information. The intra- and interspecific pairwise p-distances (proportional distance) are summarized. Some nucleotide sites with fixed status in the alignment of the COI sequences (664 nucleotide sites in length) are used as "pure" molecular diagnostic characters to delineate species in the brunnea group.