| Rosmarinic acid was always the focus of study due to its multiactive properties such as antioxidant activity, antibacterial activity, anti-inflammatory activity, anti-HIV integrase activity and Hyaluronidase inhibitor.The present paper studied the total synthesis of rosmarinic acid structural skeleton, Two new routes were designed for synthesis of the key intermediate-3,4-methylenedioxy phenyl lactic acid(5) from piperonal (Scheme 11 and Scheme 12) which was cheap and could be abtained easily. Phenyl lactic acid derivatives (6), (7), (8) and (9) were prepared by reaction of 3,4-dimethylenephenyl lactic acid(5) with allyl bromine, benzyl chloride, ethyl bromine and n-butyl bromine in the presence of K2CO3 , respectively. Rosmarinic acid derivatives(14),( 16),(1 7) and (18) were prepared by reaction of phenyl lactic acid derivatives (6),(7),(8)and(9) with 3,4-dibenzyloxycinnamic acid(ll) in the presence of DCC and DMAP, respectively. Rosmarinic acid derivatives (15) and (19) were prepared by reaction of phenyl lactic acid derivatives (6) and(9) with 3,4-methylenedioxylcinnnamic acid(13) under the same condition, respectively. The derivative of rosmarinic acid (20) was abtained by treating compound(19) with BBrs.Twenty four compounds were synthesized in the paper, among which, (7), (8), (9), (15), (16), (17), (18), (19),(20) were first synthesized, their structures were identified on the basis of spectral technology(FT-IR, 1 H-NMR,MS).Additionally, the anti-bacterial properties of compounds (14),(15),(16),(17),(18),(19),(20) were studied. The structure-activity relationships were established elementarily by comparison of their anti-bacterial activities with those of rosmarinic acid and caffeic acid. The results indicated that hydroxyl group of phenol is essential to the antibacterial activity and the carboxyl is important to enhance the activity.Huang Longjiang (Applied Chemistry) Directed by Professor Teng Dawei and Xing Yacheng...
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