Combinatorial discovery of two-photon photoremovable protecting groups.
A design principle for a two-photon photochemically removable protecting group based on sequential one-photon processes has been established. The expected performance of such groups in spatially directed photoactivation/photodeprotection has been shown by a kinetic analysis. One particular molecular class fitting into this design, the nitrobenzyl ethers of o-hydroxycinnamates, has been presented. An initial demonstration of two-photon deprotection of one such group prompted further optimization with respect to photochemical deprotection rate. This was accomplished by the preparation and screening of a 135-member indexed combinatorial library. Optimum performance for lambda >350 nm deprotection in organic solvent was found with 4,5-dialkoxy and -cyano substitution in the nitrobenzyl group and 4-methoxy substitution in the cinnamate.
Pirrung
Michael C
MC
Department of Chemistry, Levine Science Research Center, Duke University, Durham, NC 27708-0317, USA. michael.pirrung@duke.edu
Pieper
Wolfgang H
WH
Kaliappan
Krishna P
KP
Dhananjeyan
Mugunthu R
MR
D002934:Cinnamates / Q000737:chemistry / Q000528:radiation effects; D020650:Combinatorial Chemistry Techniques / Q000379:methods*; D007700:Kinetics; D008027:Light; D008958:Models, Molecular; D009578:Nitrobenzenes / Q000737:chemistry / Q000528:radiation effects*; D010777:Photochemistry / Q000379:methods*; D017785:Photons
D002934:Cinnamates; D009578:Nitrobenzenes