Synthesis of 17H-tetrabenzo[a,c,g,i]fluorene derivatives as chiral selectors for enantiomeric separation by HPLC on porous graphitised carbon

Abstract

The synthesis of the amides 2 which are designed to be selectors containing the chiral N-(3,5-dinitrobenzoyl)cx-phenylglycine covalently linked to tetrabenzo[a,c,g,i]fluorene is described. These amides are strongly adsorbed onto porous graphitised carbon, which affords chiral stationary phases that are able to resolve both racemic aromatic alcohols 3 and the methyl esters of Fmoc amino acids 4 on microgram quantities using highpressure liquid chromatography. Two methods of preparation of these chiral phases from 2 and porous graphitised carbon are described and the stability of these phases to the chromatographic conditions and to water have also been investigated.Paper 5/02808F

Synthesis and Solubility Properties of Methanofullerenes Containing Primary Ammonium Ion Functionalities

“…It is well known that methanofullerenes comprising a closed crown ether or an open ethylene glycol structure are highly soluble in organic chlorinated solvents 12. We therefore synthesized derivatives 5 – 7 by functionalization of the two malonate “arms” with both an N ‐protected amino alcohol with an increasing number of carbon atoms ( 2b 13 and 2c 14), and monomethyl ether oligoethylene glycols 4a and 4b . Reaction of malonyl dichloride with one equivalent each of amino alcohols 2 and oligoethylene glycol derivatives 4 gave derivatives 5 – 7 in statistical yields (30–40 %).…”

“…THF (CaH 2 ) and CH 2 Cl 2 (CaH 2 ) were dried and distilled before use. Compounds N ‐ tert ‐butoxycarbonyl‐4‐aminobutanol ( 2a ),11 N ‐ tert ‐butoxycarbonyl‐5‐aminopentanol (2b ),13 N ‐ tert ‐butoxycarbonyl‐6‐aminohexanol ( 2c ),14 and fullerene derivative 16 12c were prepared according to literature procedures. 1 H and 13 C NMR spectra were recorded from solutions in CDCl 3 on Bruker 200 or AMX300 with the solvent residual proton signal or tetramethylsilane (TMS) as a standard.…”

Graphene-porphyrin single-molecule transistors

“…15 The latter is especially of interest, as it leaves the electronic structure of the molecule largely unchanged, in contrast to thiol anchors which introduce gap-type states. 24 Tetrabenzofluorene (TBF) 'butterfly' anchor groups used in this study are known to bind strongly to graphite surfaces 25 and carbon nanotubes, 26 and are robust in solvent solution. 25 Density functional theory (DFT) calculations shown in Fig.…”

Design, Synthesis, and Evaluation of ω‐(Isothiocyanato)alkylphosphinates and Phosphine Oxides as Antiproliferative Agents

“…Synthesis of (w-isothiocyanatoalkyl)diphenylphosphine oxides [29][30][31][32][33] New electrophiles-N-Boc protected w-bromoalkylamines-easily availablef rom parenta mines such as N-Boc 2-bromoethylamine( 14), [49] N-Boc 3-bromopropylamine ( 15), [50] bis-N-Boc 4-bromobutylamine (16), [51] bis-N-Boc 5-bromopentylamine (17), [52] and bis-N-Boc 6-bromohexylamine( 18) [53] were applied in the alkylation of diphenylphosphine oxide.A ll reactions were performed in pressure vials at 100 8C under microwave-assisted phase-transfer catalysis reaction (PTC) using toluene and 56 %a queousp otassium hydroxide as solvents andt etra-n-butylammonium bromide (TBABr)a sc atalyst. The protected diphenyl(w-aminoalkyl)phosphine oxides 19-23 were isolated in yields of 57-86 %a fter flash chromatography (Scheme 2).…”