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The title molecule, [C70H68N2O4P4], is a polydentate podand consisting of four etheral oxygens, two tertiary amine nitrogens and four diphenylphosphin groups. It crystallizes in the triclinic space group P1, and there is only one half a molecule in the asymmetric unit. The coordinations around the N and P atoms are pyramidal. The conformations about C20-C21, O2-C21 and O2-C22 are gauche, anti and anti, respectively. 相似文献
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Ki-Young Choi Nack-Do Sung Ki-Seob Yun Young-Soo Park Jin-Gyu Kim Il-Hwan Suh 《Acta Crystallographica. Section C, Structural Chemistry》2001,57(1):47-48
The title compound, [CuCl(C16H14N4)2]ClO4, consists of a mononuclear complex cation and a perchlorate anion. The coordination of the copper(II) ion exhibits a trigonal bipyramidal geometry, where the equatorial plane is composed of the Cl atom and two N atoms of the two pyridazine rings, and the axial positions are occupied by the N atoms of two methylpyridine rings. 相似文献
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V. A. Kuropatov V. K. Cherkasov G. K. Fukin G. A. Abakumov 《Russian Chemical Bulletin》2011,60(11):2291-2295
A reaction of 3,6-di(tert-butyl)-4-chloro-1,2-benzoquinone with disubstituted N,N-dithiocarbamates leads to zwitterionic compounds containing 2-iminio-1,3-dithiole ring annulated to the quinone skeleton. These products reversibly add acids, giving salts of the corresponding catechols; they form complexes with copper involving oxygen atoms, as well. 相似文献
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M. D. Coburn M. A. Hiskey K.-Y. Lee D. G. Ott M. M. Stinecipher 《Journal of heterocyclic chemistry》1993,30(6):1593-1595
Oxidation of 3,6-diamino-1,2,4,5-tetrazine ( 1 ) with most peracids gave 3,6-diamino-1,2,4,5-tetrazine 1,4-dioxide ( 3 ) as the major product; however, treatment of 1 with peroxytrifluoroacetic acid (PTFA) gave 3,6-diamino-1,2,4,5-tetrazine 1-oxide ( 4 ) as the major product along with a small amount of 3-amino-6-nitro-1,2,4,5-tetrazine 2,4-dioxide ( 5 ). Oxidation of 3,6-bis(S,S-dimethylsulfilimino)-1,2,4,5-tetrazine ( 6 ) with 3-chloroperoxybenzoic acid (MCPBA) gave 3-S,S-(dimethylsulfilimino)-6-nitroso-1,2,4,5-tetrazine ( 7 ), which was oxidized further with dimethyldioxirane to 3-(S,S-dimethylsulfoximino)-6-nitro-1,2,4,5-tetrazine ( 8 ). All attempts to obtain 3,6-dinitro-1,2,4,5-tetrazine ( 2 ) by further oxidation of 7 or 8 failed. 相似文献
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A (3,6)-fullerene G is a plane cubic graph whose faces are only triangles and hexagons. It follows from Euler’s formula that the number of triangles
is four. A face of G is called resonant if its boundary is an alternating cycle with respect to some perfect matching of G. In this paper, we show that every hexagon of a (3,6)-fullerene G with connectivity 3 is resonant except for one graph, and there exist a pair of disjoint hexagons in G that are not mutually resonant except for two trivial graphs without disjoint hexagons. For any (3,6)-fullerene with connectivity
2, we show that it is composed of n(n ≥ 1) concentric layers of hexagons, capped on each end by a cap formed by two adjacent triangles, and none of its hexagons
is resonant. 相似文献
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Schade D Töpker-Lehmann K Kotthaus J Clement B 《The Journal of organic chemistry》2008,73(3):1025-1030
Nomega-Methylated arginines such as asymmetric dimethyl-L-arginine (ADMA) and monomethyl-l-arginine (NMMA) are known as potent physiological inhibitors of nitric oxide synthases (NOSs). To explore a possible physiological and pharmaceutical relevance of N(delta)-methylated analogues, a synthetic scheme had to be developed that would not lead to N(delta)-methyl-L-arginine only but also to its presumed metabolites of NOS catalysis. Two basic synthetic approaches have been pursued to obtain N(delta)-methylated derivatives of L-ornithine, L-citrulline, L-arginine, and N(omega)-hydroxy-L-arginine. A first attempt utilized conventionally protected L-ornithine, i.e., the tert-butyl ester and Boc-amine, and led to three end compounds in excellent yields. Simultaneous protection of the alpha-amino acid moiety by formation of boroxazolidinones, particularly by employing 9-borabicyclo[3.3.1]nonane (9-BBN-H), proved to be a convenient option to perform side chain modifications and led to all of the desired end compounds. Additionally, enantiomeric excess (ee, %) of crucial synthetic intermediates and end compounds was determined by chiral HPLC. 相似文献
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