ORGN 891 |
| We have previously prepared a series of Donor-σ- Acceptor molecules as potential molecular rectifiers, with perylenebisimide as the acceptor. Attached to one end of the bisimide is either an alkyl swallowtail (a 9-nonadecyl group to impart solubility in nonpolar solvents) or a PEG swallowtail (a hexaoxa analog, imparting improved solubility in polar solvents). We wished to try a hybrid, tetraoxa swallowtail, for improved ease of handling of intermediates, and possible intermediate solubility of the final targets. Claisen condensation of δ- valerolactone followed by acidic decarboxylation gave the cyclic ketal 1,7-dioxaspiro[5.5]undecane. Such spiroketals are known for their stability, so their reactivity has not been much explored. However, we were able to open 1,7-dioxaspiro[5.5]undecane and convert it to its oxime by treatment with NH2OH and AcONa. Williamson conditions with 3 equiv of 2-methoxyethyltosylate alkylated the two resulting alcohol hydroxyls as well as the oxime hydroxyl. LiAlH4 reduction gave the swallowtail-amine 10-amino-2,5,15,18-tetraoxanonadecane, which was coupled with perylene tetracarboxylic dianhydride to make the bis-swallowtailed perylene tetracarboxylic bisimide. This bisimide was semi-hydrolyzed to perylenetetracarboxylic monoimide monoanhydride, which then coupled with various donors to give the D-σ-A-swallowtail targets. |
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New Reactions and Methodology
8:00 AM-11:40 AM, Thursday, 14 September 2006 Moscone Center -- Room 133, Oral
Division of Organic Chemistry |