engleski

Lariat ethers with pendant phenanthridine units. Synthesis and complexation of Na- and K-picrate

Abstract: Lariat ethers 12 and 13 with appended phenanthridine fluorophoric units have been prepared as potential fluorescent chemosensor molecules for alkaline metal salts possessing aromatic anions. The starting 8-ethyloxycarbonylamino-6-methylphenanthridine was converted via 2, 3, 6 and 7 to N-(2-tosylethyl)-derivatives 4 and 8 suitable for N-alkylations of diaza-and aza-18-crown-6. However the alkylations failed giving instead the 2-oxazolidinone derivative 5 formed by intramolecular cyclisation of phenanthridine N-carbamate derivatives 4 and 8 in basic conditions. The phenanthridine derivative 10 having benzyl instead carbamate protection on 8-amino group successfully alkylated mono- and diaza-crown ethers giving lariats 12 and 14. The subsequent removal of benzyl protection groups in acidic conditions gave lariats 13 and 15. Lariat 12 was found to form the unique Na and K-picrate complexes with the metal cation bound in the crown cavity and picrate anion intercalated between phenanthridine units.

crown ethers; lariat ethers; phenanthridine; complexes

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