【作者】 李仲振；

【导师】 李英霞； 俞飚；

【作者基本信息】 中国海洋大学 ， 药物化学， 2009， 博士

【摘要】 本文工作主要包括三部分内容,分别为采用全新发展的一种邻炔基苯甲酸酯的糖基供体进行地高辛的全合成并与常规的Schimidt供体及三氟亚胺酯供体进行结果比较;合成不同长度的2位硫酸化的岩藻糖糖链;对现有的合成伏格列波糖的一条合成路线进行工艺优化。具体情况如下所述。1.本文通过两种方法进行2、6二脱氧糖磁麻糖的合成,分别合成了全乙酰化磁麻糖邻炔基苯甲酸酯供体16(线性10步,总收率21.5%)及MBz、Ac保护的供体34(线性11步,总收率45.7%)。以化合物15及17进行制备磁麻糖Schimidt供体及三氟亚胺酯供体的尝试,选择不同的溶剂(DCM、Acetone)及常规的碱(DBU、NaH、K2CO3)分别进行了尝试,结果均以失败告终,证明了磁麻糖无法制备亚胺酯供体。通过5% H2SO4/CH3OH溶液降解地高辛以85%收率得到苷元Digitoxigenin 36。供体34在PPh3AuOTf催化下选择混合溶剂(DCM : Tol =2 : 1)在恰当的反应温度及实验操作下合成了地高辛1及其单糖39、双糖46的衍生物。实验过程中采用LiOH / NH3 / DBU / Bu2SnO / (Bu3Sn)2O / NaOMe均无法达到选择性脱除Ac保护基的目的,迫不得已情况下将所有酯基全部脱除后进行区域选择性糖苷化取得了理想的结果。合成45及47过程中立体选择性约为8 : 1,区域选择性约为6 : 1。最终通过线性总计17步,总收率16.2%完成了地高辛的全合成。2.本文从L-岩藻糖出发,以原酸酯保护的方法简单高效的合成了具有合适保护基的糖基受体60、76,糖基供体57、61、62(硫苷)、65、66(氟苷)、68及70(Schimidt供体)。硫苷供体分别采用NIS/AgOTf及Tf2O/BSP(or DPSO)/TTBP进行糖苷化尝试;氟苷供体65、66与硫苷受体60相结合合成二糖硫苷供体88;Schimidt供体以TMSOTf催化进行糖苷化。实验过程中以较理想的收率及良好的立体选择性,以逐步延伸法与汇聚式合成法相结合合成了从四糖到七糖的岩藻糖糖链84、87、98、99。但不幸的是在选择性脱除Bn保护基过程中遇到无法客服的困难,虽经多种方法进行尝试,无论采用何种方法均无法将Bn完全顺利的脱除,故不得不换用其它保护基代替Ac保护基重新对岩藻糖糖链进行合成,在另一位同学的努力下终于完成了既定目标糖链的合成。3.本文通过大量的摸索和实验,由葡萄糖出发经过制备葡萄糖内酯109、制备环己酮113及还原胺化总计13步反应以总收率25.3%制备得到伏格列波糖。制备过程中间体无需柱层析纯化,仅经过简单重结晶及洗涤等操作即可满足实验纯度的要求,大大降低了生产成本,简化了实验操作,可以应用于大规模生产。更多还原

【Abstract】 The article includes three parts. The first, a steroselective and regioselective synthesis of digitoxin with glycosyl ortho-alkynylbenzoates as doners. The second, synthesis of different length chain of L-fucose with a SO3Na group in the position of C-2 hydroxy. The third, improve an existed route to synthesis voglibose.1. The article used two methods to synthesis all Ac protected cymarose glycosyl ortho-alkynylbenzoates doner 16 (in liner 10 steps, 21.5% yield in total) and MBz and Ac protected cymarose glycosyl ortho-alkynylbenzoates doner 34 (in liner 11 steps, 45.7% yield in total) from methyl glucose. Compound 15 and 17 were used to synthesis Schimidt and trifluoroacetimidates glycosyl doner but unfortunately they couldn’t work at all in different solvent ( DCM and Acetone) and using all common used base(DBU, NaH and k2CO3). Degration of digitoxin with 5% H2SO4 / CH3OH in 85% yield to get Digitoxigenin 36. Under the catalyst of PPh3AuOTf, glycosyl doner 34 and glycosyl acceptor in mixed solvent (DCM : Tol = 2 : 1) at suitable temperature and in appropriate experiment operation got the target digitoxin 1 and its monosachride derivate 39 and dissacharide derivates 46. In the process of experiment, selectively cleave of Ac protection became a big problem. Using LiOH / NH3 / DBU / Bu2SnO / (Bu3Sn)2O / NaOMe in different solvent (THF, CH3OH, H2O et al) couldn’t get ideal result. Having no alternate, cleaving all protection groups, using regioselective glycosation method got the expected effect. The regioselectivity was 6 : 1 and steroselectivity was 8 : 1 in the process of experiment to get compound 45 and 47. At last, complete the synthesis of digitoxin in liner 17 steps in 16.2% yield. 2. L-fucose, as raw material, protected with ortho ester, synthesized the glycosyl acceptor 60, 76, thioglycoside doner 57、61、62, fluorglycoside 65、66 and Schimidt doner 68, 70 in a simple and efficient way. Thioglycoside doner was promoted by NIS / AgOTf and Tf2O / BSP (or DPSO) / TTBP; fluorglycoside and thioglycoside acceptor 60 were condensed in ideal yield to get 88; Schimidt doner was promoted by TMSOTf. In the process of our work, we got the fucose chain from 4 to 7 sacharide (84、87、98、99) in ideal yield and excellent steroseclectivity with linear strategies glycosylation and convergent block synthesis. Unfortunately, sectively cleave of Bn protection group became a shackle and couldn’t be overcome though we used all known methods. After that, changing the Ac group with other group made it possible and we had got the desired product. The newly designed route was finished by another colleague.3. the improved synthesis of voglibose was described. The glucose, as raw material, underwent glycuronic inner ester 109, cyclohexanone 113 and amination reduction important process to afford the target product in 13 steps. This improved route gave a good yield 23.5% in total. This work reduces the production cost, makes the experiment operation simple and can be apply in the large-scale production.更多还原