2050-99-9Relevant articles and documents
Syntheses and properties of zinc and calcium complexes of valinate and isovalinate: Metal α-amino acidates as possible constituents of the early Earth's chemical inventory
Strasdeit, Henry,Buesching, Insa,Behrends, Sabine,Saak, Wolfgang,Barklage, Walter
, p. 1133 - 1142 (2007/10/03)
We have studied the ligand behavior of racemic isovalinate (iva-) and valinate (val-) towards zinc(II) and calcium(II). The following solid metal amino acidates were obtained from aqueous solutions: Zn3Cl2(iva)4 (1). Zn3Cl2(val)4 (2), Zn(val)2 (3). Zn(iva)2 2H2O (4). Zn(iva)2 3.25H2O (5). Zn-(iva)2 (6), Ca(iva)2 x H2O (7), and Ca-(val)2 H2O (8). Except for complex 3, these were hitherto unknown compounds. The conditions under which they formed, together with current ideas of the conditions on early Earth, support the assumption that α-amino acidate complexes of zinc and calcium might have belonged to early Earth's prebiotic chemical inventory. The zinc isovalinates 1. 4. and 5 were characterized by X-ray crystal structure analyses. Complex 1 forms a layer structure containing four- and five-coordinate metal atoms, whereas the zinc atoms in 4 and 5 are five-coordinate. Compound 5 possesses an unprecedented nonpolymeric structure built from cyclic [Zn6(iva)12] complexes, which are separated by water molecules. The thermolyses of solids 1, 3, and 8 at 320°C in an N2 atmosphere yielded numerous organic products, including the cyclic dipeptide of valine from 3 and 8. Condensation, C-C bond breaking and bond formation, aromatization, decarboxylation, and deamination reactions occurred during the thermolyses. Such reactions of metal-bound α-amino acidates that are abiotically formed could already have contributed to an organic-geochemical diversity before life appeared on Earth.
IMPROVED SYNTHESIS OF ALIPHATIC KETONES BY THE REACTION OF ALKYLMERCURIC BROMIDES WITH NICKEL CARBONYL IN THE PRESENCE OF POTASSIUM IODIDE
Ryu, Ilhyong,Ryang, Membo,Rhee, Ilsong,Omura, Haruo,Murai, Shinji,Sonoda, Noboru
, p. 1175 - 1180 (2007/10/02)
An improved and convenient procedure for symmetrical aliphatic ketone synthesis is described, which employs the reaction of alkylmercuric bromides with nickel carbonyl in the presence of potassium iodide.