Synthesis and Mesomorphic Properties of 2-(4-Alkoxybenzoyloxy or 4-Alkoxycinnamoyloxy)-5-oxo-2,5-dihydrofurans

Abstract

Two series of p-alkoxybenzoates Ia-If and p-alkoxycinnamates IIa-IIf, each species bearing one terminal furanone, have been synthesized and characterized by IR, 13 C NMR, 1 H NMR, MS spectra and elemental analysis. The mesogenic properties of both series of furanones have been studied by polarizing optical microscopy and differential scanning calorimetry (DSC). The relationship between structures and mesogenic properties was discussed. The results show that the increased alkoxy chain length (C 7 -C 12 ) and the bridging groups between the benzene ring and the furanone ring affected the mesomorphic properties greatly, and the two series of furanones might display monotropic or enantiotropic nematic (N) or semetic C (SmC) mesophases and different mesomorpic phase temperature ranges corresponding to different carbon chain length.Scheme 1 Synthesis of 2-(4-alkoxybenzoyloxy)-5-oxo-2,5-dihydrofurans Scheme 2 Synthesis of 2-(4-alkoxycinnamoyloxy)-5-oxo-2,5dihydrofurans Results and discussion UV-Vis absorption spectraThe UV-Vis absorption data of compounds 1d, Id, 2d and IId are listed and were compared in Table 1, where it could be found that the λ max values of Id and

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