109334-46-5Relevant articles and documents
Molybdenum(VI) and Molybdenum(V) Complexes with N,N'-Dimethyl-N,N'-bis(2-mercaptophenyl)ethylenediamine. Electrochemical and Electron Paramagnetic Resonance Models for the Molybdenum(VI/V) Centers of the Molybdenum Hydroxylases and Related Enzymes
Dowerah, Dulal,Spence, Jack T.,Singh, Raghuvir,Wedd, Anthony G.,Wilson, Graham L.,et al.
, p. 5655 - 5665 (2007/10/02)
As models for the molybdenum(VI/V) centers of the molybdenum hydroxylases and related enzymes, MoO2L and MoOClL (LH2=N,N'-dimethyl-N,N'-bis(2-mercaptophenyl)ethylenediamine) have been synthesized.The structure of MoO2L hasbeen determined by X-ray crystallography.The compound crystallizes in space group P21/n, with a=10.049(2) Angstroem, b=14.538(2) Angstroem, c=12.143(1) Angstroem, β=103.73(1) deg, and Z=4.MoO2L is six-coordinate with approximate C2 symmetry, with the two thiolate S atoms trans to one another and the two tertiary amine N atoms approximately trans to the terminal oxo groups.MoO2L undergoes reversible one-electron reduction on both cyclic voltammetric and coulometric time scales to give various oxo-Mo(V) complexes.The EPR spectra of these complexes including 98Mo, 2H, and 17O substituted species, are consistent with formulation as -, cis-MoO(OH)L, -, and cis-MoO(SH)L. 1H coupling constants for cis-MoO(OH)L (1.65 mT) and cis-MoO(SH)L (1.05 mT) and the 17O coupling constants for Mo17O(17OH)L (0.25 and 0.82 mT), - (0.43 mT), and Mo17O(SH)L (0.22 mT) have been measured.MoOClL exhibit reversible one-electron electrochemical reduction in its cyclic voltammogram but decomposes upon coulometric reduction.EPR data indicate it is trans-MoOClL.Substitution of Cl- by OH-, F-, and SH- has been effected in solution.The implications of the results for the structures of Mo(VI/V) centers of the enzymes are discussed.In particular, MoVOS(OR) and MoVO(SH)(OR) (OR=bound product) are suggested as the centers responsible for the "very rapid" and "rapid" EPR signals of xanthine oxidase.An MoVO(OH) center appears to be involved in the "slow" EPR signal of xanthine oxidase and the low pH forms of sulfite axidase and nitrate reductase; the high pH forms of the latter enzymes, however, do not apear to involve a conjugate base MoVO2 center.
Medium-ring Ketone Synthesis. Intramolecular Acylation of Sulfur-stabilized Carbanions: A Model Study
Ohtsuka, Yasuo,Oishi, Takeshi
, p. 443 - 453 (2007/10/02)
Intramolecular acylation of the sulfur-stabilized carbanions of the acyclic ester 9 and amide sulfides 11 was carried out as a model study for developing an effective method for the construction of medium-ring ketones by ring closure.Reaction of 9a-c or 11a-g with lithium diisopropylamide (LDA) proceeded smoothly and the expected keto sulfides 10a-c or 12a-g, respectively, were obtained.In the cases where R1 and/or R2 in 11 were normal alkyl groups, the reaction did not take place.However, these difficulties were readily overcome either by introducing a methyl group next to the carbonyl group or by converting the sulfides into the corresponding sulfoxides or sulfones.Acylation in the allyl sulfides 11b, d, f and the allyl sulfone 20b takes place at the α-position to the sulfur atom, yielding β,γ-unsaturated ketones.A reductive removal of the sulfide moiety or its conversion into other functional groups was also examined.
