Synthesis of 1,4-Diamino-2,3-di(2-pyridyl)butane and its Dinuclear Zinc(II) Chloride Complex

Abstract

In a Henry-type reaction nitromethane reacts with N-(2-pyridylmethylidene)-methylamine (1) yielding 1-methylamino-1-(2-pyridyl)-2-nitromethane (2) in nearly quantitative yield. This orange compound decomposes slowly in an inert gas atmosphere and fast in contact with air. Therefore 2 has to be stored at −78 • C as a methanol solution. Reduction of 2 with hydrogen in the presence of a Pd/C catalyst leads to the formation of 1,4-dinitro-2,3-di(2-pyridyl)butane (3) in the rather poor yield of 12 %. The major product is the meso-isomer, meso-3, whereas only traces of (R, R)-and (S, S)-isomers of 3 are formed. A conversion of the nitro groups into amino functionalities succeeds with hydrazine hydrate in the presence of a Pd/C catalyst yielding meso-1,4-diamino-2,3-di(2-pyridyl)butane (4). Recrystallization from an aqueous solution gives 4·2H 2 O. The zinc(II) chloride complex 5 with the metal atoms in distorted tetrahedral environments can be isolated after addition of two equivalents of ZnCl 2 to 4. The molecular structures of trimeric 1, meso-3, (R, R)/(S, S)-3, meso-4, and 5 have been determined and are discussed.

Characterization of Cobalt(III) Hydroxamic Acid Complexes Based on a Tris(2-pyridylmethyl)amine Scaffold: Reactivity toward Cysteine Methyl Ester

“…Syntheses of ligands TPA, 11 (4-Cl 2 )TPA, 12 and (6-Piva)TPA 13 have been previously reported in the literature except N-((4-(pivaloylamido)-2-pyridyl)methyl)-N,N′-bis((2-pyridyl)methyl)amine, (4-Piva)TPA, that we prepared from N-((4nitro)-2-pyridyl)methyl)-N,N′-bis((2-pyridyl)methyl)amine 12 in two steps upon reduction in ethanol with hydrazine hydrate in the presence of a catalytic amount of Pd/C 14 1c). Unlike complexes 2a and 4a for which there are numerous isomers, complexes 1a, 1b, and 1c exist only as a mixture of two geometric isomers, based on whether the hydroxamic oxygen is trans to a pyridine nitrogen or to the tertiary amine nitrogen.…”

Coordination Behavior of the (Diphenylphosphanyl)[α‐(2‐pyridyl)benzyl]amide Anion toward Lithium and Zinc Cations

“…Therefore, [2‐(2‐pyridyl)ethyl]amine can only be deprotonated once, and no C–C coupling occurs under similar reaction conditions 20. Other preparative procedures are necessary to synthesize 1,4‐diamino‐2,3‐bis(2‐pyridyl)butanes 21. We were interested in the influence of a phenyl group at the methylene moiety of the (2‐pyridylmethyl)amines on the coordination behavior of ligand (H L ) – .…”