Synthesis, properties and complexation studies on 3-amino-6,6′-dimethyl-2,2′-bipyridine
摘要:
The new unsymmetrical bipyridyl ligand 6,6'-dimethyl-3-nitro-2,2'-bipyridine was prepared via coupling of 6-methyl-2-trimethylstanniopyridine and 2-chloro-6-methyl-3-nitropyridine in the presence of [Pd(PPh3)2Cl2]. Reduction of the nitro group afforded 3-amino-6,6'-dimethyl-2,2'-bipyridine (L), a model for the central subunit of the antitumour drug streptonigrin. At low temperatures, in [H-2(6)]acetone, L is planar, held in place by a hydrogen bond from the amino group to the pyridyl nitrogen in the adjacent ring. From H-1 NMR lineshape analysis the barrier to rotation about the amino-bipyridyl bond (DELTAG(b)double dagger) was estimated to be almost-equal-to 38 kJ mol-1 at 200 K. This value is significantly lower than the barrier to rotation about the biaryl bond connecting the aryl rings. In solution, L co-ordinates to Cd(II), Cu(I) and Zn(II) as a bipyridyl ligand; in these complexes the chemical shift of the amino group protons shifts upfield to ca. Delta 5 compared to L where they resonate at delta 6.5. The crystal structure of [(CdLCl2)2] was determined by X-ray diffraction methods and refined to a residual of 0.027 for 1895 independent observed reflections. The crystals are monoclinic, space group P2(1)/n, a = 9.560(2), b = 16.886(2), c = 9.577(3) angstrom, beta = 118.37(2)degrees. The complex crystallized as a dimer in which each cadmium binds three chloride ligands and a bipyridyl ligand in a distorted trigonal-bipyramidal arrangement. The relevance of these results to the structure and properties of the antitumour drug streptonigrin is discussed.
Synthesis, properties and complexation studies on 3-amino-6,6′-dimethyl-2,2′-bipyridine
摘要:
The new unsymmetrical bipyridyl ligand 6,6'-dimethyl-3-nitro-2,2'-bipyridine was prepared via coupling of 6-methyl-2-trimethylstanniopyridine and 2-chloro-6-methyl-3-nitropyridine in the presence of [Pd(PPh3)2Cl2]. Reduction of the nitro group afforded 3-amino-6,6'-dimethyl-2,2'-bipyridine (L), a model for the central subunit of the antitumour drug streptonigrin. At low temperatures, in [H-2(6)]acetone, L is planar, held in place by a hydrogen bond from the amino group to the pyridyl nitrogen in the adjacent ring. From H-1 NMR lineshape analysis the barrier to rotation about the amino-bipyridyl bond (DELTAG(b)double dagger) was estimated to be almost-equal-to 38 kJ mol-1 at 200 K. This value is significantly lower than the barrier to rotation about the biaryl bond connecting the aryl rings. In solution, L co-ordinates to Cd(II), Cu(I) and Zn(II) as a bipyridyl ligand; in these complexes the chemical shift of the amino group protons shifts upfield to ca. Delta 5 compared to L where they resonate at delta 6.5. The crystal structure of [(CdLCl2)2] was determined by X-ray diffraction methods and refined to a residual of 0.027 for 1895 independent observed reflections. The crystals are monoclinic, space group P2(1)/n, a = 9.560(2), b = 16.886(2), c = 9.577(3) angstrom, beta = 118.37(2)degrees. The complex crystallized as a dimer in which each cadmium binds three chloride ligands and a bipyridyl ligand in a distorted trigonal-bipyramidal arrangement. The relevance of these results to the structure and properties of the antitumour drug streptonigrin is discussed.
PROBLEM
To provide a method for producing an arylhydroxylamine compound efficiently and safely under mild conditions.
MEANS FOR SOLVING THE PROBLEM
The present invention relates to a method for producing an arylhydroxylamine compound, which comprises contacting a nitroaryl compound with a hydrogen source in the coexistence of a platinum catalyst supported on amino group-coordinated silica and a poisoning agent.
Copper(II) bipyridyl and iminopyridyl analogoues of streptonigrin
作者:Georgina V. Long、Margaret M. Harding、Peter Turner、Trevor W. Hambley
DOI:10.1039/dt9950003905
日期:——
The crystal structures of (3-amino-6,6'-dimethyl-2,2'-bipyridine)dichlorocopper(II) [CuL(1)Cl(2)], and aqua[3-imido-6-(methoxycarbonyl)-2,2'-bipryidine-6'-carboxylato]copper(II), [CuL(3)(H2O)], have been determined. The complex [CuL(1)Cl(2)] crystallizes in space group Pnma with a=19.434(3), b=7.427(2). c=9.403(1) Angstrom and Z=4. The structure has been refined to a final R value of 0.057 based on 680 independent reflections. The copper(ii) centre exhibits tetrahedral co-ordination to the bipyridyl nitrogens of L(1) and two chlorine atoms. Crystals of [CuL(3)(H2O)] were grown from a solution of 3-amino-6,6'-bis(methoxycarbonyl)-2,2'-bypyridine (L(2)) and excess Cu-II The complex crystallizes in space group P2(1)/n with a=3.724(2), b=14,375(3), c=22.953(5) Angstrom, beta=90.72(3)degrees and Z=4. The structure has been refined to a final R value of 0.061 based on 944 independent reflections. The Cu-II centre is square planar with a slight tetrahedral deformation, and co-ordinates to an imino nitrogen. adjacent pyridyl nitrogen, carboxylate oxygen and a water molecule. The implications of these results on the types of complexes formed by streptonigrin are discussed.
US8455690B2
申请人:——
公开号:US8455690B2
公开(公告)日:2013-06-04
Synthesis, properties and complexation studies on 3-amino-6,6′-dimethyl-2,2′-bipyridine
作者:Georgina V. Long、Sue E. Boyd、Margaret M. Harding、Irmi E. Buys、Trevor W. Hambley
DOI:10.1039/dt9930003175
日期:——
The new unsymmetrical bipyridyl ligand 6,6'-dimethyl-3-nitro-2,2'-bipyridine was prepared via coupling of 6-methyl-2-trimethylstanniopyridine and 2-chloro-6-methyl-3-nitropyridine in the presence of [Pd(PPh3)2Cl2]. Reduction of the nitro group afforded 3-amino-6,6'-dimethyl-2,2'-bipyridine (L), a model for the central subunit of the antitumour drug streptonigrin. At low temperatures, in [H-2(6)]acetone, L is planar, held in place by a hydrogen bond from the amino group to the pyridyl nitrogen in the adjacent ring. From H-1 NMR lineshape analysis the barrier to rotation about the amino-bipyridyl bond (DELTAG(b)double dagger) was estimated to be almost-equal-to 38 kJ mol-1 at 200 K. This value is significantly lower than the barrier to rotation about the biaryl bond connecting the aryl rings. In solution, L co-ordinates to Cd(II), Cu(I) and Zn(II) as a bipyridyl ligand; in these complexes the chemical shift of the amino group protons shifts upfield to ca. Delta 5 compared to L where they resonate at delta 6.5. The crystal structure of [(CdLCl2)2] was determined by X-ray diffraction methods and refined to a residual of 0.027 for 1895 independent observed reflections. The crystals are monoclinic, space group P2(1)/n, a = 9.560(2), b = 16.886(2), c = 9.577(3) angstrom, beta = 118.37(2)degrees. The complex crystallized as a dimer in which each cadmium binds three chloride ligands and a bipyridyl ligand in a distorted trigonal-bipyramidal arrangement. The relevance of these results to the structure and properties of the antitumour drug streptonigrin is discussed.