87736-90-1Relevant articles and documents
4-(1-Azi-2,2,2-trifluoroethyl)benzoic Acid, a Highly Photolabile Carbene Generating Label Readily Fixable to Biochemical Agents
Nassal, Michael
, p. 1510 - 1523 (2007/10/02)
The title compound is synthesized starting from either 4-bromobenzyl tert butyldimethylsilyl ether (5b) or 4-bromobenzyl tert-butyl ether (5c) or - most simply - from 4-bromotoluene (5a).In the first step Br was replaced by Li using n-butyllithium, then the organometallic compounds were converted into the respective trifluoroacetophenones 6a - c with N-trifluoroacetylpiperidine.The azi moiety (diazirine) was prepared from the oximes 7a - c via O-tosyloximes 8a - c plus ammonia yielding the diaziridines 9a - c and oxidation of the latter with Ag2O.Oxidation by permanganate - of the ethers after acidic cleavage - yields the title compound 12.On irradation (λ > 300 nm) 12 by elimination of N2 with a half-life period of 22 s generates the corresponding carbene.At the same time from 12 with ca. 20percent the yellow isomeric 4-(1-diazo-2,2,2-trifluoroethyl)benzoic acid (20) is formed which is photolyzed generating the same carbene as 12.The synthesis of 20 is described starting from 4-bromobenzaldehyde. - The diazirine 12 as its N-hydroxysuccinimide ester 13, or using other methods of amide synthesis, can readily be coupled to amino functions of biochemically interesting agents thus forming photoaffinity labels.
