药明康德有机合成讲义资料有机氟化合物合成共54页

含氟（⼀氟,⼆氟,三氟）化合物合成总结和应⽤⾃从1956年第⼀次出现含三氟甲基的精神类⽤药氟⾮那嗪(Fluphenazine)和1957年⾸次引⼊第⼀个含氟抗癌药物5-氟尿嘧啶(5-Fluorouracil)以来[1], 半个多世纪过去了. 近⼗年来, 隨着氟化学研究的进展和对氟原⼦及含氟取代基的深⼊了解, 药物科学家正在进⼀步开掘含氟药物这座新药研发中的⾦⼭银矿(Scheme 1)[2]. 最新统计表明, ⽬前全球含氟药物年销售额在400亿美元左右, 全球销售前200名的药物中, 含氟药物就占了29个, 销售额总计320亿美元. 由此看来含氟药物的应⽤及研发前景相当可观, 约有25%～30%的新药研发是建⽴在氟化学原料产品基础之上的. 依⽂献报道, 约15%～20%的新药都含有氟原⼦或三氟甲基等基团(图1)[3]. 据我们统计,截⽌2013年底, ⼀共有163个含氟药物接受被美国⾷品和药物管理局(FDA)的批准上市[4], 这充分说明氟原⼦是除氯原⼦之外, 第⼆个最令药物化学⼯作者喜欢的卤素原⼦. 在药物研究中, 充分利⽤构效关系(SAR)的⽅法学探索和越来越多含氟中间体的可得性, 都为含氟药物的研究提供了巨⼤的推动. ⽏容置疑, 最近⼏年的有机氟化学的研究热潮必将为新⼀波的新药探寻提供更多的⽅法和⼿段, ⽽在氟化学领域有世界⼀流的中国研究团队的参与[5], 也必将会浓墨重彩地书写药物研发的崭新⼀页. 本⽂将近年来这⼀领域的研究做⼀简述概括, 希望能为现代药物的合成研发提供帮助[6].不同于其它的卤素, 氟原⼦由于其独特的电⼦结构, 它具有最强的电负性和与氢原⼦⼀般⼤⼩的原⼦半径, 因⽽也能更加⽅便合理地取代氢原⼦⽽进⾏药物分⼦结构的微调和修饰, 阻断易代谢位点从⽽改变药物代谢的途径及代谢速度; 并通过分⼦间氢键的作⽤, 延长药物在体内的作⽤时间, 提⾼药物的⽣物利⽤度和选择性. 最值得⼀提的是, 三氟甲基由于具有很强的吸电⼦性、亲脂性和稳定性等特点, 具有很强的疏⽔性⽽表现出理想的脂溶性, 具有更好的⽣物通透性和靶向选择性, 因此在许多上巿药物和临床药物常常含有三氟甲基的芳环或杂环分⼦[7].2011年美国FDA共批准了35个⼩分⼦化学药物, 其中有7个是含氟新分⼦实体(Scheme 2);2012年共批准了33个⼩分⼦化学药物, 其中有6个为含氟有机分⼦(Scheme 3); 2013 年⼀共有8个含氟药物获批(Scheme 4). 据不完全统计, 总共有数⼗个含氟药物进⼊了临床研究, 其中⼀些代表性含氟药物见Scheme 5, 如Merck临床三期的胆固醇转运蛋⽩(CEPT)抑制剂Anacetrapib和Lilly的Evacetrapib, 这两个临床药物都含有三氟甲基和氟的芳⾹烃结构单元, 预期是药物中的重磅炸弹(Blockbuster drugs). 另外Daiichi研发的⾼效鲨烯合成酶抑制剂DF-461据称效果⽐上市的HMG- CoA还原酶抑制剂Atorvastatin(Lipitor)还要好. 可见含氟药物的研究正处于⼀个相当令⼈⿎舞的发展局⾯[8], ⽽有机氟化学的突破为这⼀药物研发的加速提供了很好的帮助.从近三年获批的含氟药物结构来看, ⼀共有17 个是氟代芳⾹烃, 有6个是含有三氟甲基的芳⾹环. 其中有2个药物既有三氟甲基⼜有氟原⼦. 显然, 有机芳⾹烃的氟化反应对新药研发是极其重要的, 为此, 本⽂就近⼏年来芳(杂)环氟化及N (n＝1, 2, 3)氟甲基化的研究进展和亮点并结合实例进⾏分析总结.芳烃和杂芳烃的氟化反应可分为亲电取代(正离⼦F＋试剂)和亲核取代(负离⼦F－试剂)两类型. 氟化反应少不了使⽤氟化试剂, ⽽且⼀般都使⽤过量的. 许多氟化试剂, 包括能提供氟正离⼦和氟负离⼦的氟化物见Scheme 6, 除了常⽤的KF, ⼀般氟化试剂都不便宜, 尤其是⼀些制备困难的有机氟试剂, 价格尤为昂贵.1.1 利⽤含氮(胺基、酰胺等)芳(杂)环为原料使⽤含氮杂环的联苯衍⽣物, Sanford⼩组[9]在2006年⾸先发展了有效的氟化反应(Eq. 1), 在10 mol% Pd(OAc)2 存在的条件下, 选择性地引⼊了氟原⼦. 这也是在钯(II)催化下, 温和氧化条件下利⽤亲电的氟化试剂(F＋, 不同于使⽤亲核氟试剂F－)成功进⾏的经由直接C—H活化、氧化氟化(Oxidative fluorination)的创新反应.2009年, Scripps的Yu等[10]利⽤钯盐催化的、邻位导向基诱导的C—H活化策略, ⽤F＋试剂在NMP为促进剂的情况下有效地制备了邻位含氟的芳⾹化合物(Eq. 2).不难看出, 上述⼏个反应都是在邻位导向基(direc- ting groups)存在下钯(II)催化的亲电氟化反应, 反应经历了环钯化(Cyclopalladation)和亲电氟化两过程. 巧妙的是, 分⼦内氮原⼦从不同的形式(如吡啶中的N; 取代的胺和酰胺)作为供电⼦体, 参与了分⼦内环钯化过程, 其特点是形成有利的五元钯(II)络合物中间态(Scheme 8).在没有导向基存在的条件下, 钯催化的亲电氟化反应的机理如图所⽰(Scheme 9). ⾸先是通过转移⾦属化⽽形成的碳钯键, 由于不涉及到环钯化(cyclopallada- tion), 也不需要导向基, 因此反应底物的多样性就更加⼴泛, 缺点是底物要进⾏预官能团化, 必须引⼊适当的基团进⾏转移⾦属化(transmetalation). 随后通过亲电氟化试剂氧化将Pd(II)络合物转化为Pd(IV)的络合物, 进⽽通过还原消除⽣成C—F键.1.2 利⽤芳基锡烷/有机硼化物为原料利⽤铜盐催化, Sanford⼩组[13]发展了温和条件下的芳基锡烷和三氟硼酸钾的氟化反应(Scheme 11).最近, Hartwig ⼩组报道[14]了铜盐催化下, 利⽤F＋试剂对有机硼酸酯的氟化反应(Scheme 12).反应条件相对温和, 虽然铜试剂和银试剂的⽤量较⼤. 与此同时, 通过对19F NMR的考查, 确证了Cu(III)氟络合物的存在. 鉴于有机硼酸酯易得, 这⼀新⽅法为制备氟代芳烃⼜提供了⼀个新⼿段.1.3 利⽤芳基锡烷为原料使⽤不同的银盐(AgOTf, Ag2O)催化剂, Ritter 等[19,20]在2009年和2010年先后⾸先发展了温和条件下的芳⾹锡烷的氟化反应(Scheme 14), 并取得了良好的实验结果.1.4 利⽤芳⾹碘化物为原料和卤素交换反应(Halex processes)Hartwig⼩组[21]发现在铜盐和AgF的作⽤下, 取代碘苯能够有效地进⾏卤素交换⽽制备相应的氟苯(Scheme 15). 据机理研究表明, 该反应有Cu(0)和CuF2的形成. 反应没有完成催化循环.1.5 利⽤取代的苯酚和苯酚衍⽣物为原料从取代的苯酚和含羟基的取代的杂芳烃为起始原料, Ritter ⼩组[25]利⽤新颖的脱氧氟化试剂, 成功进⾏了操作简易可⾏的酚类化合物的氟化(Eq. 5). 该转化具有反应的产率⾼、基团兼容性好等优点.2009年Buchwald教授[27]⾸先报道了以三氟甲磺酸酯为原料的钯催化的亲核氟化反应, 成功的关键是⾤⽤了空间位阻⼤的特殊膦配体, 并通过形成刚性T形的的单核三配位的钯(II)络合物⽽完成反应. 有趣的是, 在⼀些反应中发现有区域异构体产⽣, 产物以间位产物为主(Scheme 19). 虽然⽬前对形成区域异构体的机理并不⼗分清楚, 但通过氟负离⼦进攻在原位的(in situ)产⽣的苯炔活泼中间体的解释基本排除在外.1.6 利⽤芳⾹胺和酰替苯胺为原料芳⾹胺重氮盐的HF/吡啶(Sandmeyer reaction)处理和氟硼酸处理(Balz-Schiemann reaction)是制备氟代芳烃的⽼⽅法. 使⽤有机⾼价碘, Li 和Meng等[30]成功进⾏了免除⾦属的直接区域选择性氟化酰替苯胺衍⽣物, 将氟原⼦引⾄酰替苯胺基的对位(Scheme 21). 该⽅法具有操作安全、试剂易得、条件温和、产率较⾼等特点.1.7 利⽤芳基碘鎓盐和季铵盐为原料最近, Sanford ⼩组[31]也成功研究出相转移条件下, 铜盐催化的不对称⼆芳基碘鎓盐的亲核氟化反应(Eq. 8). 该反应具有条件温和、反应快速、产率⾼、选择性好、显⽰很好的基团兼容性以及没有位置异构体等优点.1.8 后氟化(Late-stage fluorination)反应制备药物和天然产物的氟代衍⽣物Ritter⼩组[19,20]利⽤他们率先发现的银盐催化的后氟化(Late-stage fluorination)反应策略, 成功制备了数⼗个重要的上市药物和天然产物的氟代衍⽣物, 其中包括氟代Taxol、氟代DOPA、氟代Rifamycin S和氟代Camptothecin等(Scheme 22).胡⾦波等[33]于2009年已将选择性⼆氟甲基化和单氟甲基化做了很好的综述. 相对于芳烃的三氟甲基化和芳⾹烃的氟化反应, 芳烃和杂芳烃的⼆氟甲基化研究略显薄弱, ⽅法学⽅⾯的研究也显零散. 但这⼀状况最近得到了很⼤的改观. 在这⾥我们对近年的新进展做⼀概括.虽然迄今为⽌, 仍然没有上巿的药物中含有⼆氟甲基(CHF2)芳杂环亚结构单元的APl, 但是⼆氟甲基独特的结构特点仍然吸引了许多药物化学家的注意. 在等排物为基础的药物设计中, CHF2不失为优秀的亲脂性的氢键供应者, 为传统的氢键供应源提供了新的选择, 并且同时能有效地改善药物的膜渗透性, 促进药物的吸收. 例如在抗丙肝病毒(HCV NS3)蛋⽩酶抑制剂的研发过程中[34], 成功地利⽤⼆氟甲基取代并模仿母体化合物中硫醇的功能. 在COX-2和5-LOX双重抑制剂的研发过程中[35], ⼆氟甲基可做为异羟肟酸中羟基的等排物.传统的⼆氟甲基(CF2H)的引⼊⼀般都是由芳⾹醛和DAST试剂的反应⽽完成的. 考虑到有机磺酸盐中C—S键(272 kJ/mol)⽐有机硼酸C—B (377 kJ/mol)键和有机分⼦中的C—C 348 kJ/mol)要弱许多, Scripps 的Baran⼩组[36]成功制备了含⼆氟甲基结构的亚磺酸锌盐(DFMS), 利⽤过氧化叔丁醇为引发剂, 有效地均裂C—S键, 成功地制备了CF2H游离基, 并成功开发了相关反应(Scheme 23).值得注意的是, Baran ⼩组对⼀些天然产物和上市的重磅炸弹药物, 如辉瑞制药的Chantix进⾏了后三氟甲基化(Late-stage trifluoromethylation)和后⼆氟甲基化(Late-stage difluoromethylation)过程, 在不同的反应条件下, 经过不同的反应机理, 在母体化合物上有效地引进了CF3和CF2H官能团(Scheme 24), 这不失为药物创新改造和开拓构效关系(SAR)研究的新⽅法和快速通道. 从某种意义来说, 后N (n＝2, 3)氟甲基化也是将芳(杂)环电⼦云密度⼤或着是电⼦云密度⼩的C—H键(即反应的活性位点)通过亲电取代和亲核取代这两种截然不同的反应被C—CF3(或C—CHF2)健取代, 应该是阻⽌药物氧化代谢的极好⼿段, 也是提⾼药物⽣物利⽤度的⽅便策略.将著名的Ruppert-Prakash试剂(TMSCF3)经过硼氢化钠还原, Hartwig ⼩组[40]以70%的收率制备了新的⼆氟甲基化试剂TMSCF2H, 并成功应⽤于铜盐催化的⼆氟甲基化碘苯(Eq. 12), 反应的收率⾼, 操作简单易⾏, 对各种官能团具有良好的兼容性.类似于三氟甲基(CF3)、单氟甲基(CH2F)可以被认为是甲基的有⽤的⽣物电⼦等排体. 其原因是氟的强吸电⼦效应使得氟原⼦能避免甲基的代谢性氧化. ⽽且单氟甲基也被认为是羟甲基(CH2OH)和甲氧基甲基(CH2OCH3)的⽣物电⼦等排体. 据调查, 真正意义上的单氟甲基化⽅法⼏乎不存在, 尤其是通过产⽣单氟甲基游离基. 应该承认单氟甲基化是难度很⼤、富有挑战的研究热点, 但这⽅⾯的⼯作最近取得了很⼤的进展, 其中包括Scripps的Baran教授的新试(CH2FSO2)2Zn及⽅法[37](Scheme 26).使⽤活性的芳⾹酮如9-芴酮作为可见光下苄基氢的捕⾷物, Chen⼩组[38]⾸次报告了选择性产⽣苄基游离基并通过加成氟游离基⽽完成苄基氟化的催化循环(Eq. 14). 值得⼀提的是通过巧⽤、活⽤不同的芳⾹酮作为光催化剂, 有效⽅便地制备了多达数⼗个结构各异、官能团兼容的带有氟甲基⽀键的芳⾹烃. 应该指出的是这也是迄今为⽌苄基氟化反应的最新进展.传承优秀的中国氟化学研究团队数⼗年来科研成果突出, 硕果累累, 亮点不断, ⼀直深受国际学术界的赞叹, 最近中国科学院上海有机化学所的卿凤翎教授[5]已经将近年来(2009～2011年)三氟甲基化的研究进展做了较为深⼊的总结和归纳. 北京⼤学王剑波教授[42]最近也对经由三氟甲基⾃由基进⾏的三氟甲基化的⼀些基本理论问题做了很好的探讨, ⽽西班⽛的氟化学专家Grushin也对⾦属参与的芳烃三氟甲基化在Chem. Rev上发表了系统全⾯的综述[43]. 考虑到对三氟甲基化反应研究⽅兴未艾[44], 这⽅⾯的⾼⽔平研究论⽂层出不穷, 我们仅将近年以来三氟甲基化研究的亮点从简易⽅便即实⽤性, ⾼效催化即绿⾊性和安全放⼤即⼯艺合理性等⾓度做⼀点评, 挂⼀漏万有偏颇之处, 在所难免.近年来, 不少新型的三氟甲基化试剂, 如正离⼦型的、负离⼦型(Scheme 27)的和游离基型的CF3来源, 它们为进⾏亲电、亲核和游离基三氟甲基化提供了选择的可能, 并成为反应条件优化必须考虑的主要因素.过渡⾦属催化的三氟甲基化反应在有机氟化学家和⾦属有机化学家的联⼿努⼒下, 已经取得了突破性的进展(Eq. 15). 但不可否认, 和成熟的钯催化的交叉偶联反应(Suzuki, Heck, Negishi)相⽐较, 改善的空间仍然是巨⼤的, 其主要缺陷是⼀般情况下钯催化剂的⽤量较⾼(10%), 三氟甲基化试剂⼀般较为昂贵, ⽽且有些试剂为⽓体或低沸点⼩分⼦, 物理化学性质不理想也是⼤⽓臭氧层的破坏者, 再者, 过渡⾦属的含量在药物分⼦API中的控制也是必须考虑的因素之⼀. 从这个⽅⾯来讲, Scripps 的Baran⼩组[45]在Langlosi⼩组[46]前期⼯作基础上将便宜易得的三氟亚磺酸钠作为三氟甲基源, 过氧叔丁醇作为氧化剂⽽进⾏的杂环的直接三氟甲基化. 由于反应不需要⾦属催化剂, 能在室温下进⾏, 反应条件温和, 溶剂为⽔/⼄腈(也不需额外处理), 对各种取代基及官能团不需保护和耐受性好, 是⼀种实⽤价值很强且易放⼤和⼯业化的好⽅法, 堪称⼀⼤突破. 当然对⾃由基参与的化学反应, 反应热的控制和安全性评价是必不可少的.有趣的是, 该三氟甲基化反应是通过⾃由基中间体完成的, 因此反应的区域选择性并不是⾼度专⼀的, 从某种程度来说, 它对现存药物的三氟甲基化⽽带来的新的药物分⼦的多样性确是⼀件好事, 因为芳烃或杂环分⼦有多于⼀个的活性反应点, ⽽便利地引⼊三氟甲基改造现有药物分⼦不失为⼀种旧药改造的捷径. Scheme 28 列出了⼀系列经过后三氟甲基化(Late-stage trifluoromethylation)的天然产物和重磅炸弹, 我们相信许多药物研发的科学家也会逐渐学习接纳这⼀新⼿段.Gooβen 研究⼩组[50]随后报道了铜盐催化下, 使⽤Ruppert试剂(TMSCF3)以芳⾹胺为原料的桑徳迈尔反应制备三氟甲基化芳烃(Scheme 31). 有所不同的是, 他们使⽤的催化剂是⼀价铜盐, 其中以硫氰化铜(CuSCN)催化活性最⾼. 反应温度为室温, 有很好的官能团兼容性, 产率在40%～98%之间.王剑波等[51]⾸先报道了通过三氟甲基银(AgCF3)和芳⾹胺参与的桑德迈尔反应来完成胺基⾄三氟甲基的官能团转化(Scheme 32). 值得⼀提的是, 反应需要在－78 ℃下完成, 否则收率较低.三氟甲基银是通过AgF和TMSCF3来制备的, 有趣的是: 使⽤CuCF3 为试剂, 在相似条件下, 产物的收率不佳(37%). 避免使⽤超低温反应条件(－78 ℃)也许是将来反应优化、⾛向适⽤性的发展⽅向之⼀.Baran研究⼩组[45]在利⽤便宜易得的三氟亚磺酸钠进⾏芳烃三氟甲基化⼯作的基础上, 最近⼜成功地从三氟亚磺酰氯和锌粉在⽔为溶剂中制备了物化性能更加优越的新试剂三氟亚磺酸锌, 并成功应⽤于芳⾹烃的三氟甲基化反应(Scheme 34). 利⽤该试剂, Baran研究⼩组对⼀些天然产物,药物中间体也进⾏了后三氟甲基化(Late stage trifluoromethylation), 并取得了理想的实验结果. 肖吉昌⼩组[55]也⾸次报道了铜促的采⽤三氟甲基锍盐的三氟甲基化碘代芳杂(稠)环的新⽅法(Eq. 22). 该反应具有官能团兼容性好、反应条件温和、产率⾼等优点, 对不同杂环系统的三氟甲基化均取得了很好的结果. 据称反应机理涉及到铜还原锍盐产⽣活泼中间体CuCF3的单电⼦转移过程.值得⼀提的是, 2010 年Yu等[59]利⽤⼀系列杂环如吡啶、嘧啶、咪唑和噻唑为邻位导向基, 在Pd(OAc)2的催化和TFA为促进剂的联合作⽤下, 成功地利⽤C—H活化⽅法进⾏了芳环的三氟甲基化, 取得了良好的实验结果(Eq. 26).20世纪80年代⾄90年代初, 陈庆云院⼠领导的研究团队[60]先后发现了数个三氟甲基化的试剂[5],其中1991年报道的1,1-⼆氟-1-氯代⼄酸甲酯(MCDFA)在KF和CuI存在下在DMF溶剂中能有效地进⾏相应酯的热分解(100～120 ℃), 通过消除CO2和CH3X, 完成相应的三氟甲基化反应, 反应具有条件相对温和、产率⾼、试剂便宜易得等优点, 该⽅法被称为陈试剂(陈⽅法, Eq. 27), 并⼴泛被国内外学术界和药业应⽤于含三氟甲基的化合物的合成.2013年Senanayake等[61]使⽤陈试剂, 在研发抗感染药物中, 通过条件优化并使⽤控制滴加的⽅法、溶剂筛选, 确定了最佳反应条件,有效控制了放⼤反应中泡沫CO2以及三个副产物的形成,成功制备了关键中间体(Eq. 28). 值得⼀提的是, 鉴于1,1-⼆氟-1-氯代⼄酸甲酯(MCDFA)在⼯业⽣产中⼤规模⽣产, 其成本要⽐使⽤Ruppert试剂降低85%.在⼯艺研发GSK3β抑制剂AZD8027的过程中, AstraZenca的Witt等[64]⾯临着同样如何有效和⽅便地引⼊氟原⼦和三氟甲基的问题. 很显然, 通过⽤Selectfluor引⼊氟原⼦后缩合形成氟代嘧啶杂环是极不可取的(Scheme 38). ⼀是氟化试剂昂贵, ⼆是氟化产率低(50%～55%), ⽽且有中间体不稳定等缺点.改进的合成⽅法⾸先合成了含氟嘧啶和含三氟甲基的咪唑⽚断, 然后通过杂环的Ziegler偶联关键反应等有效制备了AZD8926, 改进过的合成⽅法更趋合理(Scheme 39), 产率更⾼. 同时把钯催化的胺化反应提前, 避免了消除痕量钯⾦属所带来的困扰和API的损失.经过这些年的不懈努⼒, 有机氟化学在诸多⽅⾯得到了迅猛的发展, 世界⼀流的研究⼩组你追我赶, 创新⽴异, 成果频出. 应该承认, 有机⾦属化学的进展、催化反应的应⽤是今天氟化学进展的主推动⼒. 最近在有机化学的期刊上很难看到不含有氟化学的论⽂. 许多有关氟化学的专著也陆续出版[65], 综述⽂章和研究论⽂也不断更新[66].在这⾥, 我们将近年来芳⾹烃氟化反应和芳⾹烃杂环化合物N (n＝1, 2, 3)氟甲基化反应的研究进展⽤图⽰的形式进⾏概括总结(Schemes 40, 41), 并概述了近年来含氟药物的研究成果. 值得特别强调的是第(III)种反应类型即新颖的氧化氟化反应(Oxidative fluorination)和氧化三氟甲基化反应(oxidative trifluoromethylation)是近⼏年来的研究热点课题之⼀. 我们相信最近的氟化学进展必将为药物研发⼯作者进⾏⼴泛的药物合成研究开辟了崭新的道路. 毫⽆疑问, 它必将拓展含氟药物建筑全新分⼦的想象空间, 提供更多重要的⽅法和途径.从发展趋势和⽅向来看, (1)理想的氟化反应应该是⽆⾦属(Metal-free)参与的或者是⾼效的过渡⾦属催化的过程, 应该⼤⼒开掘新颖⾼效的催化系统; (2)从经济、绿⾊环保等⽅⾯和为⼯业化放⼤⽣产考虑, Pd等催化剂的⽤量应该尽量控制在0.5～1 mol%之间(⽬前⼀般为5～10 mol%左右); (3)氟原⼦和N氟甲基的引⼊先后(现在⼀般的氟化物原分离纯化较难, 区域选择性不好⽽附带各种含氟杂质; (4)利⽤便宜易得的氟试剂, ⽬前许多含氟试剂较贵; (5)操作简单的⼯艺, 反应应该有不怕氧不怕⽔等优点, 安全且重复性好; (6)反应应该具有⾼产率, 尤其是含氟中间体和产物料都是市场上购⼊含氟⼩分⼦), 理想的状态应该是后加⼊F, ⽬前缺陷是: 收率⼀般并不太⾼, 产物纯品纯度不够, 如何进⾏分离纯化对⼯艺开发也是⼀个很⼤的挑战, 因为⼀般⽽⾔, 含氟化合物在多数有机溶剂中的溶解度⽐母体化合物更佳, 这使得利⽤重结晶、打浆等⼿段富积含氟化合物更趋不可能.应该指出的是, ⽬前在候选药物结构单元中什么位置引⼊氟原⼦和三氟甲基团, 仍带有相当的随意性, 仍然不能利⽤分⼦设计和计算化学的⽅法得到确切的判断. 也就是说含氟化合物的⽣理活性与分⼦结构的构效关系只能在⼀定程度上进⾏预测, 没有形成系统的理论体系. 显然这也是对药物科研⼯作者在含氟药物的合成与创新、开发⾼效低毒的新型药物提出的挑战.综上所述, 经过这⼏年有机氟化学家、有机⾦属化学家和药物化学⼯作者的共同努⼒, 在许多世界⼀流实验室参与和不⽢⼈后的研发热潮中, 有机氟化学的研究⾯貌发⽣了根本性的变化,极⼤地推动了含氟药物、多肽蛋⽩质化学和化学⽣物学的发展, 对材料科学和理论化学的发展也产⽣了很⼤的推动(Scheme 42). 毫不夸张地说, 这些年是有机氟化学发展的黄⾦时代, 它所创造的崭新氟化学反应⼿段和策略,为药物化学家开拓含氟药物这座宝藏提供了机遇和创造空间,也激发和丰富了有机化学家和药物科研⼈员的创造性和想象⼒,含氟药物仍是今后很长⼀段时间药物研发的⼀个热点课题, 这也是摆在中国有机化学家和药物科研⼈员⾯前的⼀⼤机遇和挑战.声明:。

经典化学合成反应标准操作药明康德新药开发有限公司化学合成部编写前言有机合成研究人员在做化学反应经常碰到常规的反应手边没有现成的标准操作步骤而要去查文献，在试同一类反应时，为了寻找各种反应条件方法也得去查资料。

为了提高大家的工作效率，因此化学合成部需要一份《经典合成反应标准操作》。

在这份材料中，我们精选药物化学中各类经典的合成反应，每类反应有什么方法，并通过实际经验对每类反应的各种条件进行点评，供大家在摸索合成条件时进行比较。

同时每种反应的标准操作，均可作为模板套用于书写客户的final report，这样可以大大节省研究人员书写final report的时间，也相应减少在报告中的文法错误。

另外本版是初版，在今后的工作中我们将根据需要修订这份材料。

药明康德新药开发有限公司化学合成部2005-6-28目录1.胺的合成a)还原胺化b)直接烷基化c)腈的还原d)酰胺的还原e)硝基的还原f)叠氮的还原g)Hoffman降解h)羧酸通过Cris 重排2.羧酸衍生物的合成a)酰胺化的反应b)酯化反应c)腈转化为酯和酰胺d)钯催化的插羰反应e)酯交换为酰氨3.羧酸的合成a)醇氧化b)酯水解c)酰胺的水解d)腈的水解e)有机金属试剂的羰基化反应f)芳香甲基的氧化4.醛酮的合成a)Weinreb 酰胺合成醛酮b)醇氧化c)酯的直接还原d)有机金属试剂对腈加成合成酮5.脂肪卤代物的合成a)醇转化为脂肪溴代物通过PBr3 转化通过PPh3 与CBr4 转化HBr直接交换通过相应的氯代物或磺酸酯与LiBr交换、b)醇转化为脂肪氯代物通过SOCl2转化通过PPh3 与CCl4 转化HCl直接交换c)醇转化为脂肪碘代物通过PPh3 与I2 转化通过相应的氯代物或磺酸酯与NaI交换6.芳香卤代物的合成a)Sandermyyer 重氮化卤代b)直接卤代c)杂环的酚羟基或醚的卤代7.醇的合成a)羧酸或酯的还原b)醛酮的还原c)卤代烃的水解d)吡啶的氧化转位8.酚的合成a)Sandermayer 重氮化反应b)醚的水解c)Bayer-vigerlar 氧化d)硼酸的氧化9.腈的合成a)磺酸酯或卤代烃的取代b)酰胺的脱水c)芳卤代烃的氰基取代10.硝化反应11.醚的合成a)芳香醚的合成酚与烷基卤代烃的直接烷基化Mitsunobu 芳香醚化Buckwald芳香醚化b)脂肪醚的合成醇的醚化12.脲的合成a)胺与异腈酸酯的反应b)用三光气合成脲c)羰基二咪唑（CDI）合成脲d)对硝基苯酚碳酰胺合成脲13.烯烃的合成a)Wittig 反应b)羟基的消除c)Wittig-Horner 反应合成α,β-不饱和酯14.磺酸及磺酰氯的合成a)氯磺化反应合成磺酰氯b)从硫醇合成磺酰氯c)磺化反应15.氨基酸的合成a)Streck 反应合成b)手性氨基酸的合成16.偶联反应a)Suzuki Couplingb)Buckwald 芳胺化，芳酰胺化、c)Heck 反应17.Mitsunobu 反应a)醇的反转b)胺的取代18.脱羟基反应19.酮还原为亚甲基20.氨的保护及脱保护策略a)用碳酰胺作保护基b)苄基保护21.醇的保护及脱保护策略a)用硅醚进行保护b)其他醚类保护22.羧基的保护格氏反应---------------------------------------------------------------------------------------------------------1还原胺化---------------------------------------------------------------------------------------------------------2卤化反应---------------------------------------------------------------------------------------------------------2 Suzuki coupling-------------------------------------------------------------------------------------------------2磺化反应---------------------------------------------------------------------------------------------------------3酯化反应---------------------------------------------------------------------------------------------------------3水解反应---------------------------------------------------------------------------------------------------------3硝化反应---------------------------------------------------------------------------------------------------------4 n-BuLi------------------------------------------------------------------------------------------------------------4 LiAlH4还原-----------------------------------------------------------------------------------------------------4 POCl3的杂环氯代----------------------------------------------------------------------------------------------5 NaH---------------------------------------------------------------------------------------------------------------5 NBS---------------------------------------------------------------------------------------------------------------5m-CPBA ----------------------------------------------------------------------------------------------------------6EDC ---------------------------------------------------------------------------------------------------------------6用三光气成脲---------------------------------------------------------------------------------------------------7芳卤用n-BuLi 处理后与Weinreb 酰胺成酮-----------------------------------------------------------------7Boc 上保护OHH 2NHO OOOOOO OHN HO OHO O ABTo a solution of A (2.72 g, 13.9 mmol) and tetramethylammonium hydroxide pentahydrate (5.62 g, 31.0 mmol) in acetonitrile (270 mL) was added di-tert-butyldicarbonate (3.79 g; 17.4 mmol) and the resulting solution was allowed to stir 18 h at rt and concentrated. The residue was partitioned between Et2O/H2O; the phases were separated and the aqueous phase extracted twice more with Et2O. The aqueous phase was brought to pH 4 with solid citric acid and extracted with CHCl3 (3.x.100 mL). The organic extracts were combined, dried (Na2SO4) and concentrated to afford 2.58 g (63 percent) B as a white foam.ReturnBoc 脱保护OON HOOOOH 2NTert-Butyl 2-(2-methoxyphenoxy)ethylcarbamate (23.8 g, 89 mmol) in dichloromethane (10 ml) was cooled to 0 deg C and stirred as a mixture of trifluoroacetic acid: dichloromethane (1:1, 40 ml) was added dropwise. The mixture was allowed to warm to rt, stirred for 2 hours and concentrated in vacuo. The residue was taken back up in dichloromethane (100 ml) and the solution was washed with saturated aqueous sodium hydrogen carbonate (3*20 ml) and aqueous sodium hydroxide (10percent, 3*20 ml), dried (Na2SO4), filtered and concentrated in vacuo to provide 2-(2-methoxyphenoxy)ethylamine (13 g, 88percent yield) as a light yellow solid.Return格氏反应NCNNOA stirred mixture of magnesium turnings (23.6 g, 0.98 mol) and Et2O (200 mL) under nitrogen is treated with a crystal of iodine and about 5percent of a solution of bromoethane (56.3 ml, 0.75 mol) in Et2O (375 mL). When the reaction starts, the remainder of the bromoethane solution is added, dropwise at a rate sufficient to maintain a gentle reflux. After the addition, stirring is continued for 1 hour. To this solution of ethylmagnesium bromide was slowly added a solution of 4-cyanopyridine (39 g, 0.375 mol) in Et2O (750 ml). The reaction mixture was warmed at reflux for 12 hours, treated with concentrated H2SO4 (125 ml)/H2O (125 ml), and then washed three times with Et2O (250 ml). The aqueous portion was made basic (PH 9) with 15percent NaOH solution and extracted five times with 250 ml portions of Et2O. The combined Et2O extracts were dried (MgSO4), and the solvent was removed under reduced pressure to afford a brown oil (48.4 g, 95percent).Return还原胺化OHO H 2N+HON HA solution of 2-amino-4-ethylphenol (1.00 g. 7.28 mmol), 2-naphthaldehyde (1.13 g, 7.28 mmol), andp-toluenesulfonic acid (0.05 g) in methanol (50 ML) was stirred at room temp for 24 h. To the resultant solution, sodium borohydride (0.82 g, 22 mmol) was added in small portions. After addition was completed, the mixture was stirred at room temperature for 30 min and concentrated under vacuum. The residue was then subjected to column chromatography on silica gel eluted with 10percent ethyl acetate in hexane and followed by recrystallization (aqueous methanol) yielded 450 mg (22percent) of analytically pure product.Return卤化反应O2N O2NBrTo a stirred solution of 8-methyl-1-nitro-naphthalene (10.6g, 56.32 mmol) and iron (III) chloride (0.45 g, 2.77 mmo) in CCl4 (150 ml) heated to 60°C was added dropwise (3.0 ml, 58.23 mmol) of bromine. After one hour, the reaction mixture was poured into saturated NaHCO3 solution, and the layers were separated. The aqueous layer was re-extracted with CH2Cl2. The combined organic layers were dried (MgSO4) and the solvent was removed under reduced pressure. The crude residue was recrystallized from ethanol and the mother liquors were concentrated and then flash chromatographed on silica, eluding hexanes:ethyl acetate (12: 1).ReturnSuzuki couplingBrBOO NH+NH To a mixture of 4-(4,4,5,5-tetramethyl-[1,3,2]dioxaborolan-2-yl)-1H-indole (2 g, 8.2 mnmol) and3-bromobenzene (0.87 ml, 8.3 mmol) in THF (28 ml) were added palladium catalyst Pd(PPh3)4 (284 mg, 0.25 mmol) and the freshly prepared sodium hydroxide solution (984 mg in 9 ml of water).The system was degassed and then charged with nitrogen for three times. The mixture was stirred under nitrogen at 70 °Coil bath for 6 hours. The reaction solution was cooled to room temperature, diluted with ethyl acetate and separated from water layer. The ethyl acetate solution was washed by brine, dried over Na2SO4 and concentrated. The residue was purified on a silica gel column eluding with hexanes: EtOAc 9:1 to give 1.38 g (78%yield) of 4-phenyl-1H-indole as a colorless liquid.Return磺化反应NOFFFNOFFFSOClOChlorosulfonic acid (4.66g, 40 mmol) is added dropwise to a cold (0°C) solution of2,3-dihydro-2-trifluoroacetyl-1H-Benz[de]isoquinoline (2.9g, 8 mmol) in chloroform (800 ml). The resulting solution is stirred at 0°C for 30 minutes. The cold bath is then removed and the solution is stirred at room temperature for 1 hour then cautiously poured into ice water. The organic layer is separated, dried over magnesium sulfate and concentrated to afford the title compound. The crude product is purified by column chromatography eluted with 10% acetic ether in petroleum ether (2.36 g, 81% yield).Return酯化反应HOHO O HOO OA mixture of 4-hydroxymethylnaphthoic acid (10 g, 50 mmol), methanol (300 ml), and concentrate H2SO4(2 ml) was refluxed overnight. The insolubles were filtered off and the filtrate was concentrated. The residue was taken up in ethyl acetate and washed with aqueous NaHCO3 (2*), brine, dried over MgSO4, and concentrated to give a yellow oil. Silica gel column chromatography using ethyl acetate/hexane (1/3) gave the desired product as a yellow oil (3.3 g, 35%yield).Return水解反应OO OHOA solution of 1-Methyl-naphthalene-2-carboxylic acid methyl ester (7.20g, 35mmol) and 2N sodium hydroxide (35ml) in tetrahydrofuran (130ml) was stirred under reflux for 18 hours. The mixture was neutralised using 2N hydrochloric acid, and extracted with dichloromethane (3x). The combined organic solutions were dried (MgSO4), and evaporated under reduced pressure. The crude product was purified by column chromatography on silica gelusing an elution gradient of dichloromethane: methanol (100:0 to 97:3) to afford the title compound as a solid (3.11g, 47.8%yield).Return硝化反应NO 2To a cold (0°C) suspension of 1-methylnaphthalene (5 g, 35.2 mmol) in HNO3 was added H2SO4 (5 ml) dropwise. After stirring the reaction for one hour, the solution was diluted with ethyl acetate and washed with water (3*), aqueous saturated NaHCO3 (2*) and brine, dried over MgSO4, and concentrated. The product was purified by silica gel column chromatography using ethyl acetate: hexane (5: 95) and recrystallized from methanol to give yellow needles (0.22g, 33% yield).Returnn-BuLiEtOCF 3O CF 3O NCTo a dry three-necked round-bottomed flask with an addition funnel and at -78°C under inert atmosphere was charged with anhydrous THF (500 ml). A solution of n-butyllithium (2.5 M in hexane, 88ml, 220 mmol) was added dropwise followed by addition of a solution of acetonitrile (10.43 ml, 200 mmol) in anhydrous THF (100 ml). The internal temperature was maintained below -70°C during the entire addition process. After 2 hr at -78°C a solution of Trifluoro-acetic acid ethyl ester (14.2 g, 100 mmol) in anhydrous THF (30 ml) was added dropwise and the mixture was stirred for 1.5 hr. To the mixture was added acetic anhydride to quench the reaction. The reaction mixture was allowed to warm up to rt. A precipitate was filtered and the filtrate was concentrated to give a brown oil, which was used in the next step without purification.ReturnLiAlH4还原HOHO O OHOHOA solution of 2,3-naphthalenedicarboxylic acid (4.6 g, 0.023 mole) in dry THF (135 ml, warmed to 50° to maintain solution) is added dropwise over 15 minutes to a 1.15 M lithium aluminum hydride solution in THF (45 ml, 0.052 mole). The solution is stirred 3 hours after which TLC indicated consumption of diacid and formation of a new major product. The reaction is quenched carefully with THF-water, then 2N hydrochloric acid (40 ml) is added, and the resulting mixture is extracted 3 times with ether. The combined ether extracts are washed with water (2 times), with saturated sodium bicarbonate solution (1 time), with water, and are dried (sodium sulfate), filtered, and concentrated to give a tan solid (3.67 g). The solid is recrystallized from ethyl acetate giving the title compound (2.91 g, 67.3%yield) as a light tan crystalline material.ReturnPOCl3的杂环氯代NN HOOHN NClClTo a suspension of 2,4-dihydroxy-5,6-dimethylpyrimidine (6.2 g, 0.044 mol) in POCl3 (25 ml) was slowly added N,N-dimethylaniline (6.18 ml, 0.049 mol). The mixture was then refluxed at 125 °C for 3 hours. After this time, the starting material completely dissolved indicating that the reaction was completed.The reaction mixture was cooled and then poured slowly onto ice to quench the POCl3(caution[exothermic]). A precipitate formed, which was filtered and washed with ice-cold water. The precipitate was dried under high vacuum overnight to yield 2,4-dichloro-5,6-dimethyl-pyrimidine (7.2 g, 0.041 mol, 92%yield) as a yellow solid.ReturnNaHHSH 2N Cl +SNH 2Sodium hydride (50% in mineral oil, 5.5 g, 0.11 mol) was added portionwise at 0 °C under a nitrogen atmosphere to a solution of 2-aminobenzenethiol (12 ml, 0.1 mol) in DMF (120 ml). After 0.5 h, benzyl chloride (11.5 ml, 0.1 mol) in DMF (80 ml) was added in 0.5 h. The solution was stirred for 3 h while the temperature was allowed to rise to rt, then it was poured into ice/water (1000 g). The precipitate was filtered, dissolved in ethyl acetate and washed with brine. The organic layer was dried over Na2SO4 and evaporated. The solid obtained was ground in pentane (19.3 g, 90% yield).ReturnNBSNN FCl ClNBSN N FCl ClBrA mixture of 2,4-Dichloro-6-ethyl-5-fluoro-pyrimidine (27.46 g ， 0.14mol), AIBN (1.32 g) and n-bromosuccinimide (27.02 g ， 0.152mol) in CH2Cl2 (170 ml) was refluxed under a nitrogen atmosphere for 36 h. Then washed by water, the aqueous was extracted by CH2Cl2. The combined organic layer was washed by saturated Na2S2O3 and brine, dried over Na2SO4, and evaporated to give a white solid which was purified by column chromatography eluted with 50% acetic ether in petroleum ether (34 g, 88.6% yield).Return氢化反应O ONH OONH2Cl ClA mixture of ethyl 3-(N-benzylamino)-3-methylbutyrate hydrochloride (25g, 0.1 mol) and 10percent Pd-C (2g) in 250 ml of dried alcohol was hydrogenated under 55 psi H2 for four days. The reaction medium was then filtered and evaporated under reduced pressure to provide an amber oil which gradually crystallized upon standing (18 g, 100% yield).Returnm-CPBAS NH2SNH2OA solution of 85% m-chloroperoxybenzoic acid (19 g, 94 mmol) in CH2Cl2 (350 ml)was added at –5 –0 °C to a solution of 2-Benzylsulfanyl-phenylamine (19 g, 88 mmol) in CH2Cl2 (400 ml). The mixture was allowed to warm to rt in 3 h, then it was washed with a 5% Na2S2O3 solution, 10% NaHCO3 solution and brine. The organic layer was dried over Na2SO4, and evaporated. The solid was ground in pentane (19 g, 95% yield).ReturnEDCNH2OHNOO+HOHOHNOOTo a 0°C mixture of Boc-L-tyrosine (2.04 g, 7.26 mmol) and amylamine (0.63 gl, 7.26 mmol) in methylene chloride (30 ml) is added 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide (EDC) (1.53 g, 9.9 mmol). Thewhite mixture is stirred at 0°C for 5 min and at room temp for 23 hrs. The resulting solution is diluted with methylene chloride (30 ml) and washed successively with 0.5 M HCl (40 ml), water (20 ml) and sat aq sodium bicarbonate (25 ml). The organic phase is dried over magnesium sulfate and concentrated to a foam (1.84 g, 72.4%yield), sufficiently pure to carry into the next step. An analytical sample is obtained by HPLC.Return三光气成脲NH 2ONO 2Si O Cl Cl ClO O Cl Cl ClO 2NHN H NO OHOHNO 2+To a solution of 2-(tert-butyldimethylsilyloxy)-4-nitroaniline (200 mg, 0.75 mmol) in toluene (10 ml) triethylamine (0.13 ml, 1.64 mmol) and triphosgene (88.4 mg, 0.3 mmol) were added. The reaction mixture was stirred at 70 °C for 2 hours, then cooled to room temperature. Then more 2-(tert-butyldimethylsilyloxy)-4-nitroaniline (200 mg, 0.75 mmol) was added. The resulting mixture was allowed to stir at 70 °C for 48 hours then cooled to room temperature. The reaction mixture was partitioned between water and ethyl acetate. The combined organic phase was washed with brine, dried over MgSO4 and filtered. Removal of solvent at reduced pressure and chromatography of the resulting oil on silica gel (hexane: ethyl acetate, 10:1) gave 1,3-Bis-(2-hydroxy-4-nitro-phenyl)-urea (130 mg, 31%yield).Return芳卤用n-BuLi处理后与Weinreb酰胺成酮N FFFFNOO+FFFO NFTo a solution of diisopropylamine (17.69 ml, 0.135 mole) in THF (200 ml) at –78°C under argon was added n-butyllithium (54.0 ml, 2.5M in hexane, 0.135 mole), followed after 5 min by dropwise a solution of 2-fluoro-4-methylpyridine (10 g, 0.090 mole) in THF (20 ml). After stirring for 15 min at –78°C, a solution of N-methoxy-N-methyl-3-trifluoromethylbenzamide (23.08 g, 0.099 mole) in THF (10 ml) was added dropwise. After stirring for more 5 min, the reaction was allowed to warm to 0°C and quenched by pouring into water (400 ml) and ethyl acetate (400 ml). The layers were separated, and the aqueous layer washed with ethyl acetate (200 ml). The ethyl acetate extracts were combined, dried over anhydrous sodium sulfate, filtered, and concentrated to an oil which was chromatographed on silica gel with 20percent ethyl acetate in hexane to give 21.6 g of 2-(2-Fluoro-pyridin-4-yl)-1-(3-trifluoromethyl-phenyl)-ethanone (84.8%yield).Return。

Pd催化的偶联反应内容简介Pd 催化的偶联反应有较多类型，目前用途最广泛的主要有以下三类:1. Suzuki 反应2. Heck 反应3. Sonogashira 反应第一部分： Suzuki 反应1. 前 言1.1 Suzuki反应的通式在钯催化下，有机硼化合物与有机卤素化合物进行的偶联反应，称之为Suzuki偶联反应，或Suzuki-Miyaura 偶联反应。

R1BY2R2X [Pd]R1R2+BY2 = B(OR)2, 9-BBN, B(CHCH3CH(CH3)2)X = I, Br, Cl, OSO2(C n F2n+1), n = 0,1,4R1 = aryl, alkenyl, alkylR2 = aryl, alkenyl, alkynyl, benzyl, allyl, alkyl[Pd] = Pd(PPh3)4, Pd(dppf)Cl2base = Na2CO3, NaOCH2CH3, TIOH, N(CH2CH3)3, K3PO41.2 Suzuki反应的机理Suzuki 偶联反应的催化循环过程通常认为先是Pd(0)与卤代芳烃发生氧化-加成反应生成Pd(II) 的络合物，然后与活化的硼酸发生金属转移反应生成Pd(II)的络合物，最后进行还原-消除而生成产物和Pd(0)。

1.3 Suzuki反应的特点及研究方向这类偶联反应有一些突出的优点：1.反应对水不敏感；2.可允许多种活性官能团存在；3.可以进行通常的区域和立体选择性的反应，尤其是，这类反应的无机副产物是无毒的并且易于除去，这就使得其不仅适用于实验室而且可以用于工业化生产。

其缺点是氯代物（特别是空间位阻大的氯代物）及一些杂环硼酸反应难以进行。

目前，Suzuki 偶联反应的研究主要在以下几个方向：1. 合成并筛选能够在温和的条件下高效催化卤代芳烃（特别是氯代芳烃）的配体；2. 多相催化体系的Suzuki偶联反应研究；3. 应用于Suzuki 偶联反应的新合成方法研究。

培训目的: 理解立体化学的基本原理. 培训后有能力区分辨别镜像立体异构体(enantiomers)和非镜像立体异构体(diastereomers), 镜像立体异构体(enantiomers)和非镜像立体异构体(diastereomers)的物理化学性质, 镜像立体选择反应(enantioselective)和非镜像立体选择(diastereoselctive)反应等培训时间: 1.5 –2小时培训内容:1. 碳原子有机化合物的异构体种类(Isomerism in Carbon Compounds)2. 镜像立体异构体(enantiomers) 和非镜像立体异构体(diastereomers)的物理化学性质3. 立体选择反应(Stereochemistry in Chemical Reactions)参考文献:1. /nbauld/teach/stereo.html#stereo2. Organic Chemistry, Solomans&Fryhle, 4th editionProperties of Enantiomers and Diastereomers 手性分子使偏振光偏转对应的镜像异构体会向相反方向偏转相同的角度!!手性色谱(HPLC, GC, etc)Properties of Enantiomers and Diastereomers1.不是所有的外消旋化合物都是可以分开的2.外消旋化合物需要在手性柱上先被分开来测量反应ee%3.绝对构型无法通过手性色谱确立，除非同已知文献报道的结果相比NNH NNBocO NNH NNBocO 外消旋化合物(普通HPLC)NNH NNBoc O=+外消旋化合物(手性HPLC)OMeOMe: 你能将上图中的四组峰和下面四个化合物一一对应吗OH OMeOH OMeOH OMe OH OMe:51问题?OH。