Synthesis of an o-Nitrobenzyl Attached A1 Adenosine Receptor Antagonist,a Prodrug Approach

Abstract

The o-nitrobenzyl group, possessing distinct advantage of being photolabile under mild conditions, was successfully connected to 8-(5,6-epoxynorbornan-2-yl)-1,3-dipropylxanthine (5), a high specific A₁ adenosine receptor antagonist. The resulting compound 4 would have potential use as a prodrug.     

Preparative Scale Stereoselective Synthesis of Methyl 4-Methyl-(Z)-2, 4-Pentadienoate

The title compound is prepared efficiently and stereoselectively by sodium methoxide induced Favorskii rearrangement and elimination of HBr from 4-methyl-1,3,4-tribromo-2-pentanone which is formed by direct bromination of mesityl oxide. The method provides mole quantities of the title compound.     

Synthesis of the 9Z and 9Z, 11E isomers of leukotriene C4

Synthesis of the 9Z and 9Z, 11E isomers of leukotriene C₄ is described, the stereochemistry of the former was confirmed by its facile 1,7 hydride shift reaction.     

新型酸性离子液体[hmim]hso4中合成乙酸酯

制备了一种新型B rφnsted酸性离子液体[Hm im]HSO4,用于乙酸与醇的酯化反应,通过简单的相分离就可以实现产物乙酸酯与离子液体的分离。考察了温度、时间、物料配比、离子液体用量等因素对乙酸与正丁醇的反应的影响,得出反应的最佳条件为:反应温度110℃,反应时间2 h,酸醇摩尔比为2,酸性离子液体[Hm im]HSO4与醇的体积比为1,乙酸正丁酯的产率为97%。离子液体重复使用5次,乙酸正丁酯的产率均大于94%。利用核磁共振、红外和元素分析测试技术对酸性离子液体[Hm im]HSO4的结构进行了表征,是以一水合物的形式存在。测定了不同浓度[Hm im]HSO4水溶液的酸强度数据,结果表明,其酸性明显高于酸性离子液体[Hm im]CF3COO的酸性。     

New Polyampholytes Based on Derivatized Polysaccharides:Synthesis,Aqueous Solution Properties and Applications

Synthetic polyampholytes combining both anionically and cationically charged species have been the focus of a number of studies due to their many potential applications^[1].However, there are few works that studied the polyampholytes derived from modified natural polymers. Recent work in our group has dealt with the grafting of a cationic monomer or a cationic monomer coupled with a neutral or anionic monomer onto carboxymethyl cellulose (CMC) as well as the grafting of a zwitterionic monomer onto hydroxyethyl cellulose (HEC) by using various initiation systems^[2-7]. Depending on the nature of used monomers, these modified polysaccharides can carry functional acidic and basic groups of different strengths.     

Studies on Synthesis and Photochromism of a Novel Class of Fulgimide： （Z）-4-Oxazolylfulgimide

A novel class of fulgimide, (Z)-4-oxazolylfulgimide ((Z)-1-benzyl-4-isopropylidene-3-[1-(2-aryl-5-methyloxazolyl)ethylidene]tetrahydropyrrole-2,5-dione), was synthesized by the reaction of (Z)-4-oxazolyl fulgide (4-isopropylidene-3-[1-(2-aryl-5-methyloxazolyl) ethylidene]tetrahydrofuran-2,5-dione) with benzyl amine. Photochromic property of (Z)-4-oxazolylfulgimide was studied. Compared with (Z)-4-oxazolylfulgide, the absorption maximum of the colored form of (Z)-4-oxazolylfulgimide is bathochromic-shifted. Substituents on the aryl ring affect the absorption maximum of the open form and the colored form of (Z)-4-oxazolylfulgimide.     

A Stereoselective Synthesis of Ethyl (2E,4Z)-2,4-Decadienoate: Pear Ester

A stereoselective synthesis of ethyl (2E, 4Z)-2,4-deca-dienoate (1) is reported from E-pent-2en-4-yn-1-ol in five steps.     

New colorimetric methods for the determination of trazodone HCl,famotidine, and diltiazem HCl in their pharmaceutical dosage forms

Two sensitive and simple spectrophotometric methods are developed for the determination of trazodone HCl, famotidine, and diltiazem HCl in pure and pharmaceutical preparations. The methods are based on the oxidation of the cited drugs with iron(III) in acidic medium. The liberated iron(II) reacts with 1,10-phenanthroline (method A) and the ferroin complex is colorimetrically measured at 510 nm against reagent blank. Method B is based on the reaction of the liberated Fe(II) with 2,2-bipyridyl to form a stable colored complex with lambda(max )at 520 nm. Optimization of the experimental conditions was described. Beer's law was obeyed in the concentration range of 1-5, 2-12, and 12-32 microg mL(-1) for trazodone, famotidine, and diltiazem with method A, and 1-10 and 8-16 microg mL(-1) for trazodone and famotidine with method B. The apparent molar absorptivity for method A is 1.06x10(5), 2.9x10(4), 1.2x10(4) and for method B is 9.4x10(4 )and 1.6x10(4), respectively. The suggested procedures could be used for the determination of trazodone, famotidine, and diltiazem, both in pure and dosage forms without interference from common excipients.     

Synthesis and Characterization of PEG-scutellarin Conjugates, a Potential PEG Ester Prodrug for the Oral Delivery of Scutellarin

Scutellarin is the active ingredient extracted from Erigeron breviscapus, a traditional Chinese herbal medicine. Pharmacological study showed that scutellarin could significantly reduce the blood viscosity, improve the blood flow, decrease the vascular re…     

The Synthesis of a New Dumbbell-shaped Compound of Bis-4,4''''-bipyridine Bridged by 2,2''''-Bipyridine

Molecular machine is a new born research field1-5, Stoddart and co-workers firstly reported a molecular shuttles in 19916. In molecular machine a cyclic (bead) moves back and forth like a shuttles between two or more groups (station) having noncovalent interaction with a bead. Dumbbell-shaped component is the key intermediate for the synthesis of molecular machines7. One of the approaches for control movement of the bead is based on coordination reaction intrigue. In our protocol, a ligand…     

Synthesis and Characterization of PEG-scuteilarin Conjugates, a Potential PEG Ester Prodrug for the Oral Delivery of Scutellarin

Highly water soluble esters of scutellarin with variable molecular weight polyethylene glycol （PEG） were prepared via PEGylation. The physicochemical properties and the stabilities under different conditions were investigated. By PEG modification, the greatly increased water solubility and desirable partition coefficient of scuteUarin were obtained, and the results showed that these conjugates were potential prodrugs for the oral delivery of scuteUarin.     

Synthesis of Some New Polyfused Thienothiophenes Part 4: Synthesis of Thienopyrimidine,Thienotriazine, Thienoimidazotriazine,Thienotriazolotriazine, and Thienotetrazolotriazine Derivatives

3,4-Diamino-2,5-dicarboxamidothieno(2,3-b)thiophene 1 was allowed to react with CS 2 , carbonyl compounds, ethyl chloroformate, S,S-acetals, and oxallyl chloride to give thienopyrimidines 2-6 and thieno-1,4-diazepine 7 . Treatment of compound 1 with nitrous acid afforded compound 8 , which converted into the corresponding chloro derivative 9 by using PCl 5 . Compound 9 was reacted with amino reagents to afford the corresponding thienoimidazotriazines 10 and 11 , thienotriazolotriazines 12 and 13 and 4-hydrazinothienotriazine 14 . Treatment of compound 14 with aldehydes, triethyl orthoformate, CS 2 , nitrous acid and ylidenemalononitriles, afforded thienotriazolotriazine 16-18 , thienotetrazolotriazine 19 , and 4-pyrazolyl-thienotriazine 20-22 derivatives respectively.     

Synthesis,Structure, and Reactivity of a Gold Carbenoid Complex That Lacks Heteroatom Stabilization

Hydride abstraction from the neutral gold cycloheptatrienyl complex [( P )Au(η¹‐C₇H₇)] ( P =P(tBu)₂(o‐biphenyl)) with triphenylcarbenium tetrafluoroborate at −80 °C led to the isolation of the cationic gold cycloheptatrienylidene complex [( P )Au(η¹‐C₇H₆)]⁺ BF₄⁻ in 52 % yield, which was characterized in solution and by single‐crystal X‐ray diffraction. This cycloheptatrienylidene complex represents the first example of a gold carbenoid complex that lacks conjugated heteroatom stabilization of the electron‐deficient C1 carbon atom. The cycloheptatrienylidene ligand of this complex is reactive; it can be reduced by mild hydride donors, and converted to tropone in the presence of pyridine N‐oxide.     

Synthesis,Structure, and Reactivity of a Gold Carbenoid Complex That Lacks Heteroatom Stabilization

Hydride abstraction from the neutral gold cycloheptatrienyl complex [( P )Au(η¹‐C₇H₇)] ( P =P(tBu)₂(o‐biphenyl)) with triphenylcarbenium tetrafluoroborate at ?80 °C led to the isolation of the cationic gold cycloheptatrienylidene complex [( P )Au(η¹‐C₇H₆)]⁺ BF₄^? in 52 % yield, which was characterized in solution and by single‐crystal X‐ray diffraction. This cycloheptatrienylidene complex represents the first example of a gold carbenoid complex that lacks conjugated heteroatom stabilization of the electron‐deficient C1 carbon atom. The cycloheptatrienylidene ligand of this complex is reactive; it can be reduced by mild hydride donors, and converted to tropone in the presence of pyridine N‐oxide.     

新型球状磷酸铁锂的合成及电化学性能

在水热条件下,制备了水合碱式磷酸铁微球,500 oC焙烧后生成直径为5μm的碱式磷酸铁,接着与碳酸锂一起焙烧后生成了球形磷酸铁锂．我们的方法可以有效地控制所获得产物的尺寸和形貌,同时在产物表面形成均匀碳包覆,改善了磷酸铁锂的电化学性能．     

Synthesis and protective effect of 1,3,5-triazine derivatives, leukotriene C4 antagonist, on HCl.ethanol-induced gastric lesions in rats.

2,4-Diamino-[E]-6-[2-(3-pyridyl)ethenyl]-1,3,5-triazine (3a), leukotriene C4 (LTC4) antagonist, was found to possess a protective effect on HCl.ethanol-induced gastric lesions. Analogues of 3a were synthesized and evaluated for the effect as well as antagonistic activity against LTC4-induced contraction. Seven compounds (3a-d, f-h) exhibited a potent protective effect on gastric lesions which was considered to be based on the antagonistic activity against LTC4. The structure-activity relationships of the derivatives (3a-k) are discussed.