- Bacterial dioxygenase- and monooxygenase-catalysed sulfoxidation of benzo[b]thiophenes
-
Asymmetric heteroatom oxidation of benzo[b]thiophenes to yield the corresponding sulfoxides was catalysed by toluene dioxygenase (TDO), naphthalene dioxygenase (NDO) and styrene monooxygenase (SMO) enzymes present in P. putida mutant and E. coli recombinant whole cells. TDO-catalysed oxidation yielded the relatively unstable benzo[b]thiophene sulfoxide; its dimerization, followed by dehydrogenation, resulted in the isolation of stable tetracyclic sulfoxides as minor products with cis-dihydrodiols being the dominant metabolites. SMO mainly catalysed the formation of enantioenriched benzo[b]thiophene sulfoxide and 2-methyl benzo[b]thiophene sulfoxides which racemized at ambient temperature. The barriers to pyramidal sulfur inversion of 2- and 3-methyl benzo[b]thiophene sulfoxide metabolites, obtained using TDO and NDO as biocatalysts, were found to be ca.: 25-27 kcal mol-1. The absolute configurations of the benzo[b]thiophene sulfoxides were determined by ECD spectroscopy, X-ray crystallography and stereochemical correlation. A site-directed mutant E. coli strain containing an engineered form of NDO, was found to change the regioselectivity toward preferential oxidation of the thiophene ring rather than the benzene ring.
- Boyd, Derek R.,Sharma, Narain D.,McMurray, Brian,Haughey, Simon A.,Allen, Christopher C. R.,Hamilton, John T. G.,McRoberts, W. Colin,More O'Ferrall, Rory A.,Nikodinovic-Runic, Jasmina,Coulombel, Lydie A.,O'Connor, Kevin E.
-
scheme or table
p. 782 - 790
(2012/02/05)
-
- A New Indirect Application of Aggregative Activation: Synthesis of Esters by Cobalt-Catalyzed Carbonylation of Aryl, Heterocyclic, and Vinyl Halides under Atmospheric Pressure
-
Sun lamp illuminated alkoxycarbonylation of aryl, heteroaryl, and vinyl halides was performed under atmospheric pressure of CO in the presence of a cobalt catalyst in situ generated from Co(OAc)2.Illunination through a Pyrex flask was sufficient to catalyze the reaction.This process avoids the use of Co2(CO)8 and excess CH3I, which were required in the earlier procedure.A SRN1 mechanism is proposed.
- Marchal, Joel,Bodiguel, Jacques,Fort, Yves,Caubere, Paul
-
p. 8336 - 8340
(2007/10/02)
-
- Carbonylation of Aryl Halides and Vinyl Bromides Mediated by Tetracarbonylcobalt Anion
-
The reaction of aryl halides (1a-g) with octacarbonyldicobalt in the presence of methyl iodide and sodium hydroxide under phase-transfer conditions was found to give a mixture of aryl methyl ketones (2a-g) and aromatic carboxylic acids (3a-h).From vinyl halides (9a-c), however, the corresponding carboxylic acids (10a-c) were obtained exclusively.
- Miura, Masahiro,Akase, Fumiaki,Shinohara, Masato,Nomura, Masakatsu
-
p. 1021 - 1026
(2007/10/02)
-
- A DIRECT SYNTHESIS OF BENZYLTHIOPHENE-3-CARBOXYLIC ACID FROM BENZOTHIOPHENE
-
The direct synthesis of benzothiophene-3-carboxylic acid from benzothiophene utilizing Friedel-Crafts acylation with trichloroacetyl chloride, followed by basic hydrolysis is presented.
- Bonjouklian, R.
-
p. 711 - 714
(2007/10/02)
-