西他列汀关键中间体的合成研究

3-氧代-4-(2,4,5-三氟苯基)-丁酸甲酯是合成二肽基肽酶-IV抑制剂类药物磷酸西他列汀的关键中间体。以2,3,5-三氟苯胺为原料,先经过重氮化反应得到1,2,4-三氟苯,再在溴素和三氯化铝的作用下収生亲电叐代,得到2,4,5-三氟溴苯;然后与丙二酸二乙酯缩合,再经氢氧化钠水解、盐酸酸化、加热脱羧得到纯品2,4,5-三氟苯乙酸,最后与2,2-二甲基-1,3-二恶烷-4,6-二酮缩合后水解得到3-氧代-4-(2,4,5-三氟苯基)-丁酸甲酯,总收率达到61.9%。产品经核磁氢谱和核磁碳谱表征。该路线能有效减少副产物,适合工业化生产。     

喹诺酮化合物5，7-二氨基-1-环丙基-6，8-二氟-1，4-二氢-4-氧代喹啉-3-羧酸的合成研究

研究5,7-二氨基-1-环丙基-6,8-二氟-1,4-二氢-4-氧代喹啉-3-羧酸（1）的合成路线和工艺。原料2,3,4,5-四氟苯甲酸经硝化、酰氯化、缩合,水解脱羧等多步反映得到中间体2,中间体2与叔丁胺亲核取代后,酸水解,氢化还原得到目标化合物。     

2,3-二氟-4-羟基苯硼酸的合成

本文以邻二氟苯为原料,利用其定位效应,通过与丁基锂、硼酸三甲酯直接作用得到2,3-二氟苯硼酸,再通过与H2O2反应得到2,3-二氟苯酚。以所合成的2,3-二氟苯酚为原料,通过叔丁基二甲基氯硅烷保护酚羟基,再在低温下与丁基锂、硼酸三甲酯等作用得到2,3-二氟-4-羟基苯硼酸,5步反应总产率为83%。     

一种西他列汀的合成方法

<正>本发明公开了一种西他列汀的合成方法,该方法以2,4,5-三氟苯甲醛为起始原料,经Wittig反应,盐酸水解得到2-(2,4,5-三氟苯基)乙醛,再与(R)-(+)-叔丁基亚磺酰胺缩合得到对应的缩醛,得到的产物通过和溴乙酸乙酯的Reformatsky反应,然后水解得到对应的有机酸,该酸再和3-(三氟甲基)-5,6,7,8-四氢-[1,2,4]三唑并[4,3-a]吡嗪盐酸盐缩合得到西他列汀的叔丁基亚磺酰胺的缩醛,最     

1-环丙基-6,7-二氟-1,4-二氢-8-甲氧基-4-氧代-3-喹啉硼二乙酯的合成研究

用螯合法把化合物1-环丙基-6,7-二氟-1,4-二氢-8-甲氧基-4-氧代-3-喹啉羧酸乙酯(DFQ-Et)螯合制得硼螯合物(1-环丙基-6,7-二氟-1,4-二氢-8-甲氧基-4-氧代-3-喹啉羧硼二乙酯)[DFQ-B(OAc)2],并考察了此步反应在DMF、DMSO等不同溶媒以及不同温度和不同时间时的反应情况。筛选结果显示,此步缩合反应的溶媒采用DMSO,所得产物(粗品)的纯度可达到大于90.0%(HPLC归一法)。总收率92.4%。该工艺反应条件温和,原料易得,操作简便,产率高,成本较低,适合工业化生产。     

2,7-二甲基-2,4,6-辛三烯-1,8-二醛的制备方法

2,7-二甲基-2,4,6-辛三烯-1,8-二醛是合成类胡萝卜素系列化合物(如β-胡萝卜素,角黄素和虾青素,番茄红素等)的关键中间体,采用乙缩醛和乙基(1-丙烯基)醚加成反应得到1,1,3-三乙氧基-2-甲基-丁烷,裂解合成得到1-甲氧基-2-甲基-1,3-丁二烯;和氯化试剂合成生成4,4-二乙氧基-3-甲基-1-氯丁烯;与三苯基膦成盐合成得到膦盐;膦盐在双氧水作用下缩合,并用碳酸钠溶液生成1,1,8,8-四甲基-2,7-二甲基-2,4,6-辛三烯;再在酸性条件下水解合成制备。     

2，2＇-二羟基-1，1-联萘-4，4＇-二羧酸的合成

BINOL类配体是一类重要的具有C2轴、不含手性中心的不对称联芳香化合物。文章将3-硝基-1-萘酸用亚硫酸铁还原成胺,并生成稳定的硫酸盐,之后重氮化,用沸腾的稀硫酸水解成酚,再成酯,最后用三氯化铁在水中偶联合成化合物2,2’-二羟基-1,1＇-联二萘-4,4’-二羧酸。并探讨了各反应过程中的影响因素。     

一种经济有效的制备2,4,5-三氟苯乙酸的新方法

2,4,5-三氟苯乙酸是合成治疗II型糖尿病药物的关键中间体,同时也是合成新型含氟除草剂的重要中间体.本文以2,3,5,6-四氟对苯二甲酸二乙酯为原料,通过亲核取代、水解和脱羧三步反应得到2,4,5-三氟苯乙酸,总产率达到92％以上.该合成方法工艺简单,产率高,适合工业化生产.     

2′,4′-二氟-4-羟基联苯的制备

以2,4-二氟联苯为原料,经由Friedel-Crafts酰化、Baeyer-Villiger重排和水解制备得到2′,4′-二氟-4-羟基联苯,总收率为71.6%.     

（-）反式-4R（4-氟苯基）-3S-羟甲基-1-甲基哌啶的合成

亚磷酸三乙酯与氯乙酸乙酯进行缩合、重排、脱氯乙烷合成磷酸酯，再与对氟苯甲醛经Knoevenagel反应合成肉桂酸酯，肉桂酸酯与丙二酸二乙酯胺解合成的N-甲胺基羰基乙酸乙酯环合得到哌啶二酮，环化物用硼氢化钾复合还原剂还原得混旋帕罗醇，混旋体进行手性拆分得（4R，3S）-4-氟苯基-3-羟甲基-1-甲基哌啶目标物。选择car1#、cat2#、cat3#为各步催化剂，反应收率分别为89．1％，96．3％，86．5％，76．3％，87．2％，43．7％，总收率24．3％，比旋光度-36—38°，纯度大于99％。     

一种高效氧化3-羟甲基-7β-苯乙酰胺-3-头孢-4-羧酸二苯甲基酯的方法

以7-氨基头孢烷酸(7-ACA)为原料,经水解、氨基和羧基保护,制得3-羟甲基-7β-苯乙酰胺-3-头孢-4-羧酸二苯甲酯(Ⅰ),产率48%;并在乙腈中用2-碘酰基苯甲酸实现羟基选择性氧化,产物3-甲酰基-7β-苯乙酰胺-3-头孢-4-羧酸二苯甲酯(Ⅱ),收率达94%。     

无水氯化镁和三乙胺催化合成β-酮酸酯

以丙二酸二乙酯为原料,在氢氧化钾条件下将其转变为丙二酸单乙醇酯钾盐,研究丙二酸单乙醇酯钾盐在无水氯化镁-三乙胺碱体系作用下,与酰氯反应制备β-酮酸酯的方法。产物结构经1H NMR、质谱、元素分析确证。该方法避免使用格氏试剂、氢化钠、丁基锂等强碱,条件温和,操作简单,成本低,适合在实验室和工业生产中制备β-酮酸酯。     

Electrosynthesis of β-methylpentadecanedioic acid dimethyl ester

β-Methylpentadecanedioic acid dimethyl ester ( I ) was synthesized electrochemically by Kolbe reaction using β-methylglutaric acid monomethyl ester ( II ) and α,ω-dodecanedioic acid monomethyl ester (III) as starting materials in MeOH solution. Electrolysis was carried out ofr about 4–5 h, when solution pH ≥ 7, followed by extraction with petroleum ether and distillation to obtain a colourless oily product ( I ) The minimum production cost occurred when the mole ration of II to III was 1:1·38 and unreacted III could be recovered. The product synthesized ( I ) completely met the requirement of artificially synthesized musk.     

芳基重氮化合物与烯胺的合成反应研究

α-重氮苯乙酸酯与N-(苯乙烯基)-吗啉在铜盐催化下的反应,能够以高的化学产率制备手性γ-酮酯。详细讨论了γ-酮酯的制备方法、烯胺的结构对反应的影响。     

有机催化β-酮酸酯不对称α-羟基化反应研究进展

手性α-羟基β-酮酸酯是多种天然产物及医药产品的重要中间体,获得这一类结构单元最简单的方法是β-酮酸酯的直接不对称α羟基化,因此该反应在医药工业和精细化工领域具有重要的研究价值。本文针对小分子金鸡纳碱衍生物、二萜类生物碱、芳氧基氨基醇及手性相转移催化剂直接氧化β-酮酸酯不对称α-羟基化反应研究,该反应的催化机理被认为是氢键、π-π键等多种分子间力协同作用,同时还需要适当的位阻基团遮蔽以获得羟基化反应立体选择性。     

替米沙坦的合成工艺改进

以3-甲基-4-硝基苯甲酸(Ⅰ)为起始原料,经多步反应合成了替米沙坦(Ⅸ)。3-甲基-4-硝基苯甲酸经酯化、还原、酰化、硝化、还原、环合反应得到2-正丙基-4-甲基-6-羧基苯并咪唑(Ⅶ),在多聚磷酸的作用下Ⅶ与N-甲基邻苯二胺缩合,生成的产物(Ⅷ)再与4′-溴甲基联苯-2-羧酸甲酯缩合、水解得替米沙坦Ⅸ。其总收率从1993年文献[3]的20.9%提高到30%。该产品已在河南天方药业股份有限公司中试。     

Synthesis of 7,10-dihydroxy-8(E)-octadecenoic acid

We report the synthesis of 7,10-dihydroxy-8(E)-octadecenoic acid (DOD), which has recently also been reported from bioconversion of oleic acid. One hydroxyl of 1,7-heptanediol was protected as tetrahydropyranyl ether, and the other hydroxyl was used for chain extension by two carbonsvia Wittig reaction to give ethyl 9-tetrahydropyranyloxy-2(E)-nonenoate, an α,β-unsaturated ester, which on Dibal-H reduction offered allylic alcohol. The epoxidation at the double bond followed by conversion of the hydroxyl group to chloro gave 9-tetrahydropyranyloxy-2,3-oxirane-1-chlorononane. Treatment of this epoxy nonyl chloride with excess of LiNH₂/liquid NH₃; followed by addition of 1-nonanal, gave 18-tetrahydropyranyloxy-9, 12-dihydroxy-10-octadecyne. The lithium aluminum hydride reduction of the conjugated hydroxy acetylenic bond, protection of hydroxyl groups as benzoates and oxidation of the primary ether group, followed by removal of benzoate groups, gave DOD. IICT Communication No. 2995.     

How is chemical interesterification initiated: Nucleophilic substitution or α-proton abstraction?

Esters of carboxylic acids including 2-methylhexanoic, 2-methylbutyric, 2,2-dimethyl-4-pentenoic, palmitic, and oleic acids were tested as substrates in methoxide-catalyzed interesterification and transesterification. The aliphatic acid esters participated in the ester-ester interchange upon addition of catalytic sodium methoxide. Their isopropyl esters also produced methyl esters on heating with sodium methoxide. The esters of α-methyl-substituted acids did not participate in the ester-ester interchange. Their isopropyl esters did not react with methoxide to produce methyl esters. However, upon addition of methanol with sodium methoxide, their methyl esters were produced. These results indicate that the first step in interesterification is possibly that methoxide abstracts the α-hydrogen of an ester to form a carbanion. Interesterification is then likely completed via a Claisen condensation mechanism involving the β-keto ester anion as the active intermediate. The β-keto ester anion contains positively charged ketone and acyl carbons that are active sites for nucleophilic attack by anions such as methoxide and glycerinate, which would produce a methyl ester or rearrange acyls randomly. On the other hand, transesterification is a nucleophilic substitution by methoxide at the acyl carbon in the presence of methanol.     

Reduction of fatty ester Δ2-isoxazoline heterocycles. Preparation of fatty esters containing the β-hydroxy ketone moietyheterocycles. Preparation of fatty esters containing the β-hydroxy ketone moiety

Fatty ester compounds containing the β-hydroxy ketone moiety were prepared in good yields from their corresponding fatty Δ²-isoxazoline heterocyclic precursors by a reductive hydrogenolysis-hydrolysis procedure using Raney nickel as catalyst. By this methodology, C-17, C-18, and C-19 straight-chain fatty methyl esters containing the 10-hydroxy 12-keto moieties were prepared in 73, 83, and 92%, respectively, from their corresponding isoxazoline fatty ester compounds. Two other 10-hydroxy 12-keto C-12 and C-14 fatty ester compounds were prepared in 84 and 92% yield, respectively. The C-12 β-hydroxy ketone contains a phenyl ring at C-12, whereas the C-14 β-hydroxy ketone compound has two methyl substituents at C-13. GC-MS using electron impact ionization was used to determine the hydroxyl and ketone positions after conversion of the hydroxyl group into its corresponding trimethylsilyl ether. The precursor fatty ester Δ²-isoxazolines used in this study are readily available in one step from a 1,3-dipolar cycloaddition reaction between nitrile oxides and methyl 10-undecenoate. This overall two-step sequence, 1,3-dipolar cycloaddition followed by reductive ring opening, represent a convenient method to construct fatty ester compounds in good yields containing the β-hydroxy ketone functionality, an outcome not easily accessible by other methods.     

Dynamic covalent cross-linked polymer gels through the reaction between side-chain β-keto ester and primary amine groups

A dynamic covalent gel network was constructed via the coupling reaction between the pendant primary amine groups of poly(l-leucine methacryloyloxyethyl ester) (P(H₂N-Leu-EMA)) and the side-chain β-keto ester functionalities of poly(2-(acetoacetoxy)ethyl methacrylate) (PAEMA) by varying the molar ratios of P(H₂N-Leu-EMA)/PAEMA and the concentration of polymers in different solvents at room temperature. Fourier transform infrared (FT-IR) spectroscopy and solid-state ¹³C nuclear magnetic resonance (NMR) study confirmed the newly formed enamine bonds in the polymeric gel. Rheological studies showed that the mechanical strength of gels increased with increasing weight percentage (wt.%) of polymers in solution. Furthermore, polymer gels can be transferred to the mixture of starting polymer solutions by regulating the pH of the system, which can be further transformed into the gel state by adding an external base.