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Fluorescence Assay and Screening of Epoxide Opening by Nucleophiles
Author(s) -
Badalassi Fabrizio,
Klein Gérard,
Crotti Paolo,
Reymond JeanLouis
Publication year - 2004
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.200400024
Subject(s) - chemistry , epoxide , nucleophile , umbelliferone , azide , moiety , hapten , bromide , stereochemistry , medicinal chemistry , organic chemistry , catalysis , coumarin , antibody , immunology , biology
Terminal epoxides such as 1 react with nucleophiles (H 2 O, Cl − , Br − , N 3 − , and CN − ) at the primary oxirane carbon atom to give mostly anti‐Markovnikov‐type regioisomers 5a − d . The opening products of epoxide ( R )‐ 1 with chloride ( 5a ), bromide ( 5b ) and azide ( 5c ) are oxidized by horse liver alcohol dehydrogenase and NAD + to give the corresponding ketones 7a − c and, subsequently, umbelliferone 4 by β‐elimination, leading to a fluorescence increase at λ em = 460 ± 20 nm (λ ex = 360 ± 20 nm). The epoxide hydrolysis products give no signal. We used this enantio‐ and chemo‐selective fluorogenic assay for epoxide opening to search for catalytic antibodies for nucleophilic epoxide opening that were raised against 1,2‐azidoammonium hapten 8 , as a mimic for epoxide opening by azide, and against chloromethyl phosphonate hapten 9 , as a mimic for the transition state of chlorohydrin formation. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)