24017-92-3Relevant articles and documents
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Lucien,Taurins
, p. 208,221 (1952)
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Enantioselective route to 5-methyl-And 5,7-dimethyl-6,7-dihydro-sh- dibenz[c,e]azepine: Secondary amines with switchable axial chirality
Pira, Silvain L.,Wallace, Timothy W.,Graham, Jonathan P.
supporting information; experimental part, p. 1663 - 1666 (2009/09/06)
(-) -5-Methyl-6, 7-dihydro-5H-dibenz[c, e]azepine 4, a new secondary amine featuring an axis-center stereochemical relay, was prepared enantioselectively from 2'-acetylbiphenyl-2-carboxylic acid, using (R) -2-phenylglycinol as an auxiliary for the control
Dioxygen Transfer from 4a-Hydroperoxyflavin Anion. 2. Oxygen Transfer to the 10 Position of 9-Hydroxyphenanthrene Anions and to 3,5-Di-tert-butylcatechol Anion
Muto, Shigeaki,Bruice, Thomas C.
, p. 4472 - 4480 (2007/10/02)
The reaction of the peroxy anion of N5-ethyl-4a-hydroperoxy-3-methyllumiflavin (4a-FlEtO2-) with the anions of 3,5-di-tert-butylcatechol (VIII), 10-ethoxy-9-phenanthrol (Ia), and 10-methyl-9-phenanthrol (Ib) has been investigated.All products may be accountable through the transfer of O2 from the 4a-FlEtO2- reactant to the phenolate anions with the production of reduced flavin anion (FlEt-) and a hydroperoxycyclohexadienone.From VIII- (t-BuOH) there was obtained 3,5-di-tert-butyl-o-quinone (IX) and Ib- yielded (t-BuOH or CH2CN) 10-hydroxy-10-methyl-9,10-dihydro-9-phenanthrone (IIIb), while Ia- provided both 9,10-phenanthrenequinone (V) and monoethyl 1,1'-diphenate (IVa) (the ratio of V:IVa being solvent dependent).The mechanisms for the decomposition of intermediate peroxide anions to products are discussed.The conversion of Ia- to IVa by oxygen transfer from 4a-FlEtO2- amounts to a catalysis by FlEt- of the reaction of 3O2 with Ia and serves as a biomimetic reaction of flavoenzyme dioxygenase.The kinetic for the reaction of VIII- with 4a-FlEtO2- require the formation of an intermediate.Since the rate constants for the reaction of both VIII- and 2,6-di-tert-butyl-4-methylphenolate anion with 4a-FlEtO2- are identical under saturating conditions by these phenolate ions, it is concluded that the intermediate is formed in a unimolecular reaction from 4a-FlEtO2- (k = 0.36 s-) as in eq 19.Dissociation of 4a-FlEtO2- to FlEt-+ O2 and reaction of phenolate ions with O2 may be discounted since the second-order rate constants for the reaction of phenolate ions with O2 are less than required for the kinetic competency of this process.Dissociation of 4a-FlEtO2- to yield neutral flavin radical (FlEt.) + O2-. followed by reduction of FlEt. by fenolate ion to provide FlEt- and phenoxy radical with the coupling of the latter with O2-. is also improbable.Thus, though the second-order rate constants for 1e- reduction of FlEt. by the various phenolate species are sufficiently large to allow the kinetic competency of this step, there exists no evidence that O2-. can couple with any radical species to provide a hydroperoxide.The oxygen-donating intermediate formed from 4a-FlEtO2- is suggested to be the 4a,10-dioxetane (XII) or an oxygen molecule more loosely associated with FlEt-.The equilibrium constant for the formation of such an intermediate may be as small as 10-5 if the rate of reaction of phenolate ion with this species approaches a diffusion-controlled process.
