Nitridoosmium(VI) and nitridoruthenium(VI) complexes of cysteine(2-) and related ligands
摘要:
Anionic complexes of nitridoruthenium(VI) and nitridoosmium(VI) containing covalently bound N-acetyl-L-cysteinato, 3-sulfidopropionato, and 3-sulfidopropionamidato ligands have been synthesized to model the binding of delta-(L-alpha-aminoadipyl)-L-cysteinyl-D-valine to the iron center in the metalloenzyme isopenicillin N synthetase. The complexes are prepared by the reaction of N-acetyl-L-cysteine, 3-mercaptopropionic acid, and 3-mercaptopropionamide with [NBu(n)4][Os(N)(OSiMe3)4], [NBu(n)4][Os(N)Cl4], [NBu(n)4][Ru(N)(CH2SiMe3)4], or [NBu(n)4][Ru(N)(OSiMe3)4]. They have been characterized by elemental analysis and IR and NMR spectroscopy. Spectroscopic data show that the N-acetyl-L-cysteinato and 3-sulfidopropionato ligands are bound to the metal center through sulfur and oxygen, while the 3-sulfidopropionamidato ligands are bound through sulfur and nitrogen. The molecular structures of cis-[NBu(n)4][Os(N)(O2CCH2CH2S)2], [NBu(n)4][Os(N){O2CCH(NHCOCH3)CH2S}2], and [PPh4][Ru(N)(NHCOCH2CH2S)2)] were determined by single-crystal X-ray diffraction. These complexes were found to have distorted square-pyramidal geometry around the metal center. cis-[NBu(n)4][Os(N)(O2CCH2CH2S)2] crystallizes in monoclinic space group P2(1)/c with a = 13.718 (6) angstrom, b = 10.080 (3) angstrom, c = 19.890 (5) angstrom, beta = 92.16 (3) angstrom, and Z = 4. [NBu(n)4][Os(N){L-O2CCH(NHCOCH3)CH2S}2] crystallizes in monoclinic space group C2 with a = 18.371 (6) angstrom, b = 9.261 (1) angstrom, c = 21.125 (7) angstrom, beta = 102.92 (3) angstrom, and Z = 4. [PPh4][Ru(N)(NHCOCH2CH2S)2)] crystallizes in orthorhombic space group Pbca with a = 23.022 (1) angstrom, b = 16.120 (1) angstrom, c = 15.728 (1) angstrom, and Z = 8.
Cationic palladium(<scp>ii</scp>)-catalyzed dehydrative nucleophilic substitutions of benzhydryl alcohols with electron-deficient benzenethiols in water
An efficient direct nucleophilic substitution of benzhydryl alcohols with electron-deficient benzenethiols using cationic Pd(II) catalysts as Lewis acids in water is reported. Atom economical and environmentally benign protocols afford S-benzylated products in moderate to excellent yields. Commercially available Pd(MeCN)4(OTf)2, PdCl2(MeCN)2, and Na2PdCl4 are highlyefficientcatalysts. Notably, this
454. The carbon–sulphur fission in thio-ethers. Part I. The retarding influence of α-methyl groups and of the length of the acid chain on the alkaline hydrolysis of (2-ketoalkylthio)- and (p-nitrotriphenylmethylthio)-acetic acids
作者:Youssef Iskander、Rasmy Tewfik
DOI:10.1039/jr9510002050
日期:——
US4098824A
申请人:——
公开号:US4098824A
公开(公告)日:1978-07-04
US4127722A
申请人:——
公开号:US4127722A
公开(公告)日:1978-11-28
Catalytic Enantioselective Sulfoxidation of Functionalized Thioethers Mediated by Aspartic Acid-Containing Peptides
作者:Susannah E. Huth、Nicolò Tampellini、Maria D. Guerrero、Scott J. Miller