糖蛋白（GP）IIb/IIIa拮抗剂的合成与活性

血小板凝聚最后的共同的一步是纤维蛋白原结合糖蛋白IIb/IIIa受体，因此GPII／IIIa受体拮抗剂应优于阻断其他单一途径的抗血小板药物。合成了13个化合物，其中4个化合物在体我活性上和模板化合物相当。     

Chemoenzymatic synthesis of chiral unsymmetrical benzoin esters

A chemoenzymatic Dynamic Kinetic Resolution (DKR) of unsymmetrical benzoins (Ar¹≠Ar²) has been carried out, by using Pseudomonas stutzeri lipase stereorecognition pattern. After studying this lipase behaviour, a high preference towards acylation of those benzoins containing substituents in the phenyl ring rather than in the benzoyl moiety was observed. This fact allowed the development of the DKR process of this kind of substrates, avoiding the accumulation of secondary products derived from the in situ racemization mediated by Shvo’s catalyst action, and allowing the synthesis of enantiopure unsymmetrical benzoins acetates (not previously described) in very good yields (60-95%) and excellent enantiomeric excess values (always >99%).     

An efficient and convergent synthesis of the potent and selective H3 antagonist ABT-239

An efficient and convergent process for the preparation of a potent and selective H₃ receptor antagonist, ABT-239, 1A was accomplished with an overall yield of 64%. The key step in the synthesis is a Sonogashira coupling/cyclization reaction of 1-but-3-ynyl-2-(R)-methylpyrrolidine (9) with 4′-hydroxy-3′-iodo-biphenyl-4-carbonitrile (3). Additionally, the key amine component 2-(R)-methylpyrrolidine (7) was effectively synthesized from the readily available Boc-l-prolinol with a simple catalytical hydrogenolysis as the key step. This column chromatography-free process is highlighted by several simple work-up and purification procedures and is amendable to the large-scale preparation of 1A.     

Efficient dynamic kinetic resolution of arylamines with Pd/layered double-hydroxide-dodecyl sulfate anion for racemization

A novel and efficient racemization catalyst, Pd/layered double-hydroxide-dodecyl sulfate anion, was prepared and used in the dynamic kinetic resolution (DKR) of arylamines. The undesired enantiomer was completely racemized at 55 °C, allowing the catalyst to be compatible with biocatalysts. DKR proceeded smoothly and showed a broad substrate scope, with good conversion and high product enantiomeric excesses (ee_p). The system could be reused more than 30 times without loss of conversion and ee_p value.     

Palladium catalyzed Heck-arylation/cyclization cascade: An environmentally benign and efficient synthesis of 4-arylcoumarins in water

An environmentally benign and efficient approach for the synthesis of 4-arylcoumarins from ortho-hydroxy cinnamate ester derivatives with aryl iodides was developed in water under aerobic conditions. This transformation proceeds through a palladium catalyzed Heck-arylation/cyclization cascade reaction. The present protocol features a wide substrate scope and readily available starting materials to afford the desired products in high to excellent yields.     

基于药效团模型从中草药数据库中搜索gpIIb/IIIa受体抑制剂

选择20 个3,4-二氢-1(1H)-异喹啉酮类gpIIb/IIIa受体抑制剂作为训练集, 利用Catalyst软件包建立了gpIIb/IIIa受体抑制剂三维药效团模型. 探讨了药效团作用模式. 并通过建立的可靠性最佳的药效团模型(线性回归系数r=0.7715), 从中草药数据库中虚拟筛选了gpIIb/IIIa受体抑制剂, 通过实验活性测定得到了8个抑制ADP活化全血血小板聚集的IC50从40到100 μmol·L-1的化合物, 进一步证明了所建药效团模型的有效性.     

Highly efficient synthesis of enantiopure diacetylated C(2)-symmetric diols by ruthenium- and enzyme-catalyzed dynamic kinetic asymmetric transformation (DYKAT)

Highly efficient synthesis of enantiopure diacetates of 2,4-pentanediol and 2,5-hexanediol starting from commercially available mixtures of the diols (dl/meso approximately 1:1) has been realized by combining a fast ruthenium-catalyzed epimerization with an enzymatic transesterification. The in situ coupling of these two processes produces the diacetates in high yield in >99 % enantiomeric excess.     

A simple and efficient approach to 1,3-polyols: application to the synthesis of cryptocarya diacetate

A highly enantio- and stereoselective synthetic strategy for both syn- and anti-1,3-polyols has been developed. The sequence involves iterative Jacobsen's hydrolytic kinetic resolution (HKR), diastereoselective iodine-induced electrophilic cyclization, and ring-closing metathesis (RCM). This protocol has subsequently been utilized for the synthesis of cryptocarya diacetate, a natural product with broad range of biological activity.     

An efficient synthesis of new thiazolidin-4-one fused s-triazines as potential antimicrobial and anticancer agents

As a part of our endeavor toward the synthesis of new heterocyclic bioactive agents, two series of thiazolidin-4-one fused s-triazines were synthesized by applying an efficient palladium catalyzed C–C Suzuki coupling using catalyst system Pd(OAC)₂, Xphos and K₃PO₄ as a base in toluene solvent. Moreover, the synthesized analogs were further screened for their in vitro antimicrobial as well as anticancer efficacy against prostate cancer PC3 cells. Some compounds displayed remarkable antimicrobial activity and noticeable anticancer activity. It was observed that, both benzonitrile and nicotinonitrile are essential to increase the different pharmacological activities. The newly synthesized compounds were characterized by IR, 1H NMR, 13C NMR and MS analysis.     

Synthesis of (R)-propane-1,2-diol from lactides by dynamic kinetic resolution

The dynamic kinetic resolution (DKR) of rac-1-tert-butoxypropan-2-ol with isopropenyl acetate in the presence of Novozyme 435 and a ruthenium catalyst produces enantiomerically pure (R)-1-tert-butoxy-2-acetoxy-propane (>99.5 %ee) in a good yield. The product can be easily transformed into (R)-propane-1,2-diol without loss of stereoselectivity. Together with recently published procedures, the herein described DKR offers the possibility to use any lactide source as starting material for the production of (R)-propane-1,2-diol. The chiral diol may serve as the chiral building block for the synthesis of important enantiopure esters, like propylene carbonate, chiral polymers, etc.     

Chemoenzymatic preparation of optically active trans-cyclohexane-1,2-diamine derivatives: an efficient synthesis of the analgesic U-(-)-50,488

Stereoespecific syntheses of (+/-)-trans-N,N-cyclohexane-1,2-diamines ((+/-)-4 a-g) were carried out from the corresponding (+/-)-trans-N,N-dialkylaminocyclohexanols by successive treatment with mesyl chloride and aqueous ammonia. The stereochemical outcome indicates the formation of a meso-aziridinium ion intermediate. Kinetic resolutions of diamines (+/-)-4 were efficiently accomplished in aminolysis reactions catalyzed by lipase B from Candida antarctica with ethyl acetate as the solvent and acyl donor. Acetamides and the remaining diamines, isolated as the benzyloxycarbonyl derivatives, were obtained with very high ee values (92-99%). One of the carbamates was used as a precursor of the analgesic U-(-)-50,488.     

Temporary thio-derivatization in the synthesis of (+)-4-acetylbromoxone

A stereocontrolled synthesis of the marine natural products (+)-bromoxone (1) and (+)-4-acetylbromoxone (2) is reported. The sequence features the enzymatic kinetic resolution of 4-hydroxycyclohexenone (6) via its S-benzyl adduct. Thereafter, a base-mediated elimination-silylation generated an optically active (−)-4S-4-tert-butyldimethylsilyoxycyclohexenone (5), which then underwent diastereoselective epoxidation. Saegusa-Ito oxidation enabled formation of the corresponding α,β-unsaturated ketone 13. Bromination-elimination and subsequent removal of the silicon protecting group afforded (+)-bromoxone (1) which was converted into (+)-(4S,5R,6R)-4-acetoxy-2-bromo-5,6-epoxycyclohex-2-enone (2) [(+)-4-acetylbromoxone]. Using a luciferase gene reporter assay ED₅₀ for NFκB inhibition of 9 μM was determined.     

Enantioselective synthesis of cis-α-substituted cycloalkanols and trans-cycloalkyl amines thereof

The diastereo- and enantioselective syntheses of trans-cycloalkyl amines was accomplished through a three-step sequence consisting of: (1) asymmetric transfer hydrogenation through dynamic kinetic resolution of bicyclic and monocyclic α-substituted ketones using HCO₂H/Et₃N as the hydrogen source and TsDPEN-based Ru(II) catalysts, (2) nucleophilic hydroxyl to azide substitution of the resulting cis-cycloalkanols using diphenyl phosphoryl azide under modified Mitsunobu conditions, and (3) reduction of the trans-azide intermediates with LiAlH₄ of PPh₃/H₂O to the desired targets.     

Binding mechanism of RGD and its mimetics to receptor GPIIb/IIIa. A theoretical study

In order to better understand, at a sub-molecular level, the minimal structural requirements for the recognition process in the platelet aggregation inhibitory activity, a series of RGD mimetics were examined as fibrinogen receptor antagonists variants. We simulate the electronic interactions between RGD with its biological receptor in terms of smaller molecules. MeCOO⁻ was used to mimic the side chain of deprotonated Asp and Meguanidinium group mimicked the side chain of the protonated Arg. Alternative moieties present on the RGD mimetics were also studied in this report. AM1; RHF/3-21G; B3LYP/6-31++G^** in the gas phase. Also, B3LYP/6-31++G^** calculations using the IPCM solvation model were carried out for all the complexes. Our results indicate that high level of theory calculations and the inclusion of solvent effects are crucial in order to obtain satisfactory of accuracy in the electronic distributions of these compounds.     

A furan route to the asymmetric synthesis of trans-fused polyether building blocks

A novel route towards chiral trans-fused polyether lactones 7 and 12 has been developed starting with commercially available furfural. Sharpless kinetic resolution and ring-closing metathesis reactions served as key steps in the strategy.     

Concise Synthesis of Sibrafiban and Lamifiban,Two Non‐Peptide Fibrinogen Receptor (GPIIb/IIIa) Antagonists

The total synthesis of the non‐peptide fibrinogen receptor antagonists, sibrafiban ( 1 ) (Ro 48–3657) and lamifiban ( 2 ) (Ro 44–9883), is described. Both contain 4‐hydroxypiperidine unit and the same solid‐phase synthesis method was used as a key step. Connection of a secondary alcohol to the DHP‐resin, followed by iterative saponification and coupling sequences, provided novel drugs.     

Concise synthesis of β-blockers (S)-metoprolol and (S)-betaxolol using hydrolytic kinetic resolution

Enantiopure (S)-metoprolol and (S)-betaxolol were prepared in an extremely simple and practical way using Jacobsen's hydrolytic kinetic resolution of terminal epoxides in isopropanol.     

An efficient synthesis of benzofuran derivatives under conventional/non-conventional method

<正>l-Methyl-3-ethyl imidazolium bromide[meim]Br/basic alumina(Al_2O_3) has been found to promote the cyclocondensation of chloroacetone/chloroethyl acetate with salicylaldehydes under conventional as well as microwave irradiation to yield benzofuran derivatives.     

光学活性氰醇的合成研究进展

光学活性氰醇是合成大量医药、农药产品的重要中间体。本文介绍了通过生物或化学催化剂进行外消旋底物的拆分或前手性底物的不对称化来制备光学活性氰醇的方法,重点讨论了有较大发展前景的有机溶剂中脂肪酶催化氰醇酯的动力学拆分的方法。