ABSTRACT
An investigation into the use of core-shell particle columns for separation of short (â¼21 base pairs) RNA oligonucleotides by ion-pair reversed-phase liquid chromatography (IP-RPLC) showed improved resolution for a number of test analytes relative to conventional (fully-porous) reversed-phase columns. The best resolutions were obtained using columns packed with smaller sub-2µm core-shell particles.
Subject(s)
Chromatography, Reverse-Phase/methods , Oligonucleotides/analysis , Oligonucleotides/chemistry , Chromatography, Reverse-Phase/instrumentation , Particle SizeABSTRACT
[structure: see text] The first total synthesis of rollicosin, a member of a rare subgroup of Annonaceous acetogenins containing two terminal gamma-lactones, is reported. The approach features a highly regio- and stereoselective tandem ring-closing/cross-metathesis reaction for construction of the east-wing lactone and incorporation of the alkyl spacer. Establishment of the C4 stereocenter and addition of the west-wing lactone were achieved by Sharpless asymmetric dihydroxylation and enolate alkylation.
Subject(s)
Combinatorial Chemistry Techniques , Furans/chemical synthesis , Lactones/chemistry , Molecular Structure , Plants, Medicinal/chemistry , Rollinia/chemistry , StereoisomerismABSTRACT
A strategy for the synthesis of chiral 5-(1-hydroxyalk-2-enyl)-5H-furan-2-ones and its application to the total synthesis of (-)-muricatacin, in four steps and 37% overall yield from (R,R)-hexa-1,5-diene-3,4-diol, are described. The key synthetic step in this approach is a highly regioselective and stereoselective tandem ring-closing/cross metathesis reaction in which both lactone formation and alkyl chain extension are accomplished in an efficient one-pot process.
