Epoxidation naphthalene

Closely related substrates such as )5-methyl styrene epoxide and dihydro-naphthalene epoxide and derived trans diols were not substrates for this particular microorganism. 

Another common method for the preparation of benzene and naphthalene epoxides is by introduction of double bonds into the dihydro precursors. This is generally achieved by bromination-dehydrobromination. Thus unsubstituted benzene oxide-oxepin (86 96) can be obtained by dehydrohalogenation of the dibromocyclohexane epoxide 99, using a basic amine or sodium methoxide in ether.53... 

Brase and coworkers [29] also reported highly enantioselective desymmetrization of rran5-bicyclo[4.4.0]decadienes 81-84, which were prepared through Birch reduction of naphthalene, epoxidation and epoxide-opening reaction (Figure 13.11). The position of C=C double bonds also differed from the previous report [25], Although a Mizoroki-Heck reaction of aryl iodide 81 with the usual chiral ligands such as BINAP, DIOP i(2R,3R)- or (25,35)-0-isopropylidene-2,3-dihydroxy-l,4-bis(diphenylphosphino)butane)... 

Jerica et at. (IfiVO) have recently reported isolation of 1,2-naphthalene epoxide after incubation of labeled naphthalene with the microsomal hydroxyiation system of rat liver. 

The first reaction was involved in a synthesis of morphine, the starting ketone being made by reduction of a substituted naphthalene O. Amer. Chem. Soc., 1950, 72, 3704). No doubt an epoxide could have been used as the electrophile. 

Example Special tiases DBN (23) and DBU (24) arc exceptionally reactive in climination react ions under mild conditions. DBK allowed elimination of HBr from (25) even in the presence of the epoxide so that mono-epoxy-naphthalene (26) could be made for the first time. "... 

Some green algae are able to use aromatic sulfonic acids (Figure 2.4a) (Soeder et al. 1987) and aliphatic sulfonic acids (Figure 2.4b) (Biedlingmeier and Schmidt 1983) as sources of sulfur. Cultures of Scenedesmus obliquus under conditions of sulfate limitation metabolized naphthalene-l-sulfonate to l-hydroxy-naphthalene-2-sulfonate and the gluco-side of naphth-l-ol (Kneifel et al. 1997). These results are consistent with formation of a 1,2-epoxide followed by an NIH shift. 

Lanza, D. L. Code, E. Crespi, C. L. Gonzalez, F. J. Yost, G. S. Specific dehydrogenation of 3-methylindole and epoxidation of naphthalene by recombinant human CYP2F1 expressed in lymphoblastoid cells. Drug Metab. Dispos. 1999, 27, 798-803. 

In contrast with the behaviour of typical vinylphosphonic acid derivatives, the carbon-carbon double bond in the 1,2-oxa-phospholene (167) is remarkably unreactive towards a broad spectrum of reagents including electrophiles, most epoxidizing and organometallic reagents, as well as to dipolar addition reactants. Exceptional reagents are, however, N-bromoacetamide (NBA), ozone, dimethyllithiumcuprate, and sodium-naphthalene. 

Konishi et al.97 synthesized porphyrin compound 127. As shown in Scheme 4-44, asymmetric epoxidation of prochiral olefins such as styrene derivatives and vinyl naphthalene by iodosobenzene has been achieved by using this porphyrin complex as the catalyst in the presence of imidazole. The optically active epoxides were obtained with moderate ee. 

The arene (5 mmol) in CHCl3 (100 ml) is added to aqueous NaOCl (0.6 M, 250 ml) and the pH is adjusted to 8-9 by the addition of cone. HCl. TBA-HS04 (0.34 g, l mmol) is added and the mixture is stirred until TLC analysis shows complete conversion of the arene. The organic phase is separated, washed well with H20, dried (K2CO ), and evaporated to yield the epoxide (e.g. 90% from phenanthrene, 76% from 1,2-benz-anthracene, 70% from acenaphthene, 19% 2,3 4,5-bis-epoxide from naphthalene). 

Another isomerization reaction of arene oxides is equilibrium with oxe-pins [5], Here, the fused six-membered carbocycle and three-membered oxirane merge to form a seven-membered heterocycle, as shown in Fig. 10.2. An extensive computational and experimental study involving 75 epoxides of monocyclic, bicyclic, and polycyclic aromatic hydrocarbons has revealed much information on the structural factors that influence the reaction rate and position of equilibrium [11], Thus, some compounds were stable as oxepins (e.g., naphthalene 2,3-oxide), while others exhibited a balanced equilibrium... 

Like for benzene, the cytotoxicity of naphthalene is not due to the epoxide but to the quinone metabolites, namely 1,2-naphthoquinone and 1,4-naphthoquinone [85], As shown in Table 10.1, naphthalene 1,2-oxide (10.2) is a better substrate than benzene oxide for epoxide hydrolase. Its rapid isomerization to naphthalen-l-ol, facile enzymatic hydration to the dihydrodiol and lack of reactivity toward nucleophiles such as glutathione may explain its absence of direct toxicity [85],... 

P. J. van Bladeren, J. M. Sayer, D. E. Ryan, P. E. Thomas, W. Levin, D. M. Jerina, Differential Stereoselectivity of Cytochrome P450b and P450c in the Formation of Naphthalene and Anthracene 1,2-Oxides. The Role of Epoxide Hydrolase in Determining the Enantiomer Composition of the 1,2-Dihydrodiols Formed ,. /. Biol. Chem. 1985, 260, 10226- 10235. 

N. R. Kitteringham, C. Davis, N. Howard, M. Pirmohamed, B. K. Park, Interindividual and Interspecies Variation in Hepatic Microsomal Epoxide Hydrolase Activity Studies with cw-Stilbene Oxide, Carbamazepide 10,11-Epoxide and Naphthalene , J. Pharmacol. Exp. Ther. 1996, 278, 1018 - 1027. 

Naphthoquinone-2,3-epoxide, see Naphthalene 2-(a-Naphthoxy) -yV-ethylpropionamide, see Napropamide 2-(2-Naphthoxy)propanoic acid, see Napropamide 2-(a-Naphthoxy)propionamide, see Nanronamide 1-Naphthylamine, see Nantalam... 

An interesting case of different regiochemistry in the ring opening of an epoxide using a substoichiometric amount (60%) of naphthalene in the lithiation process was observed with epoxides 282. After the naphthalene-promoted lithiation process the most unstable... 

The anionic polymerization of epoxides such as ethylene and propylene oxides can be initiated by metal hydroxides, alkoxides, oxides, and amides as well as metal alkyls and aryls, including radical-anion species such as sodium naphthalene [Boileau, 1989 Dreyfuss and Drefyfuss, 1976 Inoue and Aida, 1984 Ishii and Sakai, 1969]. Thus the polymerization of ethylene oxide by M+A involves initiation... 

Chiral metal complexes, aUylic alcohol epoxidation catalysis, 394-401 Chiral naphthalene derivatives, singlet oxygen cycloaddition, 271... 

A versatile method for the synthesis of perhydrofuropyrans begins with 2-chloromethyl-3-(2-methoxyethoxy)pro-pene, 79. Compound 79, in the presence of lithium powder and a catalytic amount of naphthalene, undergoes sequential reaction with two electrophiles, first a carbonyl compound and then an epoxide, to form methylidenic diols. Hydroboration-oxidation, followed by oxidation with PCC, affords perhydrofuropyrans (Scheme 15) <2000TL1661, 2001SL1197, 2003T5199>. 

The oxidation of naphthalene was one of the earliest examples of an epoxide as an intermediate in aromatic hydroxylation. The epoxide can rearrange nonenzymatically to yield predominantly 1-naph-thol, interact with the enzyme epoxide hydrolase to yield the dihydrodiol, or interact with glutathione S-transferase to yield the glutathione conjugate, which is ultimately metabolized to a mer-capturic add. 

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