A convenient one-pot process for preparing various esters of caffeic acid from 3,4-dihydroxybenzaldehyde has been developed. The alcohols or phenols react with Meldrum's acid to form malonic acid mono-esters, which, without separating, immediately react with 3,4-dihydroxybenzaldehyde to afford the desired esters in good yield. The 1H NMR data and X-ray diffraction analyses indicate that these α,β-unsaturated esters are in trans (E) form in accord with natural esters.
(a) GreenawayW., and WhatleyF.R., J. Chromatogr., 1991, 543, 3113; (b) A.H. Banskota, Y. Tezuka and S. Kadota, Phytother. Res., 2001, 15, 561; (c) N. Sahinler and O. Kaftanoglu, Nat. Prod. Res., 2005, 19, 183.
2.
SonS., and LewisB.A., J. Agric. Food. Chem., 2002, 50, 486.
3.
KujumgievA., BankovaV., IgnatovaA., and PopovS., Pharmazie, 1993, 48, 785.
4.
FesenM.R., KohnK.W., and LeteurtreF., PommierY., Proc. Nat. Acad. Sci. USA, 1993, 90, 2399.
5.
OrbanZ., MitsiadesN., BurkeT.R.Jr., TsokosM., and ChrousosG.P., Neuroimmunomodulation, 2000, 7, 99–105.
6.
NatarajanK., SinghS., BurkeT.R.Jr., GrunbergerD., and AggarwalB.B., Proc. Nat. Acad. Sci. USA, 1996, 93, 9090.
7.
(a) BurkeT.R.Jr., FesenM.R., and MazumdeA., J. Med. Chem., 1995, 38, 4171; (b) M.R. Fesen, Y. Pommier, F. Leteurtre, S. Hirogushi, J. Yung and K. Kohn, Biochem. Pharmcol., 1994, 48, 595.
8.
(a) HuangM.T., MaW., YenP., XieJ.G., HanJ., FrenkelK., GrunbergerD., and ConneyA.H., Carcinogenesis, 1996, 17, 761; (b) S.C. Li, H. Li, F. Zhang, Z.J. Li and J.R. Cui, J. Chin. Pharm. Sci., 2003, 12, 184.
(a) NakanishiK., OltzE.M., and GrunbergerD., WO patent, 8 900 851, 1989; (b) B. Etzenhouser, C. Hansch, S. Kapur and C.D. Selassie, Bioorg. Med. Chem., 2001, 9, 199.
11.
SonS., LobkowskyE.B., and LewisB.A., Chem. Pharm. Bull., 2001, 49, 236.
12.
(a) NigelE.B., and PeterS.J.C., US Patent, 6 066 311, 1997; (b) Y.J. Lee, P.H. Liao, W.K. Chen and C.C. Yang, Cancer Lett. (Shannon, Irel.), 2000, 153, 51.
13.
JiangH.C., and HoC.T., J. Agric. Food. Chem., 1997, 45, 2374.
14.
EisingerM., MarkoO., and Shun-IchiroO., Science, 1985, 229, 984.
15.
(a) BankovaV.S., J. Nat. Prod., 1990, 53, 821; (b) C. Piechucki, Synthesis, 1976, 3, 187; (c) Y. Kazumasa, F. Chikara, S. Masanori, N. Youichiro and S. Tadakazu, US Patent, 4 733 002, 1988.
16.
XiaC.N., and HuW.X., J. Chem. Res., 2005, 5, 332.
17.
DavidsonD., and BernhardS.A., J. Am. Chem. Soc., 1948, 70, 3426.
