| Gibberellins,a kind of tetracyclic diterpene phytohormones,are widely existed in plants and microorganisms.They have the biological activity to promote or inhibit plant growth,which have already played important roles in agriculture.Gibberellin GA3 is a plant growth regulator which is widely used in production of hybrid rice cultivation.The A ring system of the Gibberellin is a hidden Michael receptor and the D ring also contains hidden alpha methylene cyclopentanone.The activity center of some antitumor compounds,is the alpha,beta-unsaturated ketones and alpha-methylene cyclopentanone system.Thus transformation and modification of the structure of gibberellins,such as GA3,GA4,GA7,to new Michael reaction acceptors with better activities,such as antibacterial,anticancer and antiviral,is of important academic significance and practical value.Our group has designed and synthesized a number of 3,15-dioxy-gibberellin derivatives with strong antitumor activity to cancer cells and low toxicity to normal cells.These compounds have been patented in 2004 and was authorized in 2007 with the patent number ZL200410021939.Based on the preliminary research,a new series of 13-etherial,13-halide derivatives and 1-,13-,17-amino derivatives,alkylamine,ether and nitrogen heterocyclic group in C-7 position were synthesized,some molecules have strong antitumor activity.On the basis of these research results,we describe in this thesis the design and synthesis of a new series of gibberellin derivatives bearing thiol group in position 17,1,13,as well as the A ring aromatization of gibberellins.Based on preliminary biological studies towards tumor cellines,we found that most of the new gibberellin derivatives have strong antitumor activities in vitro.This thesis have four chapters.In the first chapter,the research progress of the physiological activities and mechanism of some terpenoids as Michael reaction acceptor molecules is summarized.In the second part,we described the biological activities of gibberellin and the research progress.In the third chapter,we described in detail the synthetic studies on gibberellin derivatives from gibberellin GA3.The experiment part,including specific experimental manipulations and spectral data was documented in chapter four. |
