Acknowledgments
S. Boonyaketgoson thanks the Science Achievement Scholarship
of Thailand and Chiang Mai University for a scholarship. K. Trisu-
wan thanks the Thailand Research Fund for the TRF Senior
Research Scholar (Grant No. RTA5480002) to V. Rukachaisirikul.
The Department of Chemistry, Faculty of Science, Chiang Mai
University is gratefully acknowledged for partial support.
Supplementary data
Supplementary data associated with this article can be found, in
the online version, at http://dx.doi.org/10.1016/j.tetlet.2014.
04.105.