- Amphiphilic dendrimer, synthesis method thereof, and application of amphiphilic dendrimer as drug delivery system
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The invention relates to a microenvironment response type amphiphilic dendrimer, a synthesis method thereof, and application of the microenvironment response type amphiphilic dendrimer as a drug delivery system. The microenvironment response type amphiphilic dendrimer is a compound with a structure as shown in a formula (I), a formula (II) or a formula (III) or pharmaceutically acceptable salt of the compound. The compound disclosed by the invention can be used as the nano delivery system based on tumor microenvironment specific response, has good solubility in an aqueous solution, can be self-assembled with a drug in the aqueous solution to form a relatively stable nano compound, can effectively deliver the loaded drug to a tumor site; and can responsively disassembl the nano-drug delivery carrier under corresponding stimulation to achieve the purpose of accurate drug release, so that the drug can be released to the focus part to the greatest extent, and the compound is a novel nano-delivery carrier.
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Paragraph 0096-0097; 0105-0107; 0147-0148; 0154-0156
(2021/08/07)
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- Manganese-mediated acetylation of alcohols, phenols, thiols, and amines utilizing acetic anhydride
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Manganese(II) chloride-catalyzed acetylation of alcohols, phenols thiols and amines with acetic anhydride is reported. This method is environment-friendly and economically viable as it involves inexpensive, relatively benign catalyst, mild reaction condition, and simple workup. Acetylation is performed under the solvent-free condition at ambient temperature and acetylated products obtained in good to excellent yields. Primary, secondary heterocyclic amines, and phenols with various functional groups are smoothly acetylated in good yields. This method exhibits exquisite chemoselectivity, the amino group is preferentially acetylated in the presence of a hydroxyl/thiol group.
- Jain, Isha,Sharma, Ramandeep,Malik, Payal
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supporting information
p. 2952 - 2960
(2019/09/13)
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- Efficient synthesis of organic thioacetates in water
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Thioacetates as precursors of thiols are interesting starting points for synthesizing other organosulfur compounds. Herein, we propose a simple, efficient and fast method to obtain organic thioacetates using water as a solvent. Taking into account the great attention that has been paid toward environmentally friendly synthetic procedures in the past decades, we prove the role and the strength of the thioacetate anion as a nucleophile for nucleophilic displacement reactions in an aqueous medium. The reactions were carried out under pH control, to prevent the decomposition of the mesylate starting materials, using potassium carbonate as a safe and mild base. A simple work up allows products to be obtained with excellent yield and acceptable purity.
- Olivito,Costanzo,Di Gioia,Nardi,Oliverio,Procopio
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p. 7753 - 7759
(2018/11/02)
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- S-Acetylation of Thiols Mediated by Triflic Acid: A Novel Route to Thioesters
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This paper demonstrates an efficient, mild, and chemoselective synthesis of various thioesters via a HOTf-catalyzed S-acetylation of aromatic and aliphatic thiols using isopropenyl acetate as a cheap and convenient acetylating agent. During our tests, we also investigated the differences between the activities of metal triflates and triflic acid as catalysts in the acetylation of thiols. Finally, the potential of our concept has been increased by the implementation of Nafion as a heterogeneous catalyst for S-acetylation of thiols.
- Kuciński, Krzysztof,Hreczycho, Grzegorz
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p. 489 - 493
(2018/04/27)
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- S-Acylation of aliphatic and aromatic thiols with carboxylic acids and their esters over solid acid catalysts in the gas phase at temperatures above 200 °c
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Benzenethiol is reacted with acetic acid in a hydrogen stream over [(Mo6Cl8)Cl4(H2O) 2]·6H2O. Catalytic activity of the clusters appears above 200 °C, yielding S-phenyl thioacetate. The selectivity is 98% at 300 °C. Niobium, tantalum, and tungsten halide clusters with the same octahedral metal framework also catalyze the reaction. Benzoic acid and aliphatic carboxylic acids afford the corresponding S-phenyl carbothioates by reaction with benzenethiol. Aliphatic thiols are also S-acylated to yield the corresponding S-alkyl carbothioates. When carboxylic esters are applied to the reaction with benzenethiol over [(Nb6Cl12)Cl 2(H2O)4]·4H2O at 450 °C, the sterically unhindered moiety of the ester is incorporated into the products: S-phenyl thioacetate or methyl phenyl sulfide is obtained selectively. A Br?nsted acid site developed on the cluster complex by thermal activation is the active site of the catalyst. Hence, solid acids such as silica-alumina, zeolites, and heteropoly acids that are stable above 200 °C also catalyze these reactions.
- Nagashima, Sayoko,Yamazaki, Hitomi,Kudo, Kentaro,Kamiguchi, Satoshi,Chihara, Teiji
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p. 332 - 338
(2013/07/26)
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- Convenient synthesis of alkyl thioacetate from alkyl halide using a polymer-supported sodium thioacetate
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Alkyl halides are efficiently converted to their corresponding S-alkyl thioacetates under mild and nonaqueous conditions, using polymer-supported sodium thioacetate as a new polymeric reagent at room temperature in high yields and purity. The spent polymeric reagent can be removed quantitatively by filtration and pure products can be obtained by evaporation of the solvent. The spent polymeric reagent can be regenerated and reused several times without its activity changing appreciably. Iranian Chemical Society 2012.
- Zarchi, Mohammad Ali Karimi,Nejabat, Mojgan
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p. 767 - 774
(2013/02/23)
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- Solvent-free acetylation of thiols under catalysis of MgBr 2·OEt2
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Solvent-free protection of aromatic and aliphatic thiols with acetic anhydride was performed at room temperature under trace quantities of magnesium bromide ethyl etherate, affording rapid formation of various thiol esters in excellent yields. Copyright Taylor & Francis Group, LLC.
- Mojtahedi, Mohammad M.,Abaee, M. Saeed,Javadpour, Mashal
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experimental part
p. 2362 - 2365
(2011/02/22)
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- Flavouring and odorant thiols from renewable natural resources by InIII-catalysed hydrothioacetylation and lipase-catalysed solvolysis
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A chemoenzymatic access to thiol compounds, including ethyl 3-thiobutanoate, 3-thio-p-menthene and 8-thio-p-menthan-2-one, three compounds of interest in flavour and fragrance chemistry presenting various fruity notes, is proposed. It involves an indium(III)-catalysed hydrothioacetylation of renewable precursors followed by an enzymatic solvolysis of the obtained thioesters by lipases in aqueous or organic solvents.
- Dia, Reine-Marie,Belaqziz, Rim,Romane, Abderrahmane,Antoniotti, Sylvain,Du?ach, Elisabet
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supporting information; experimental part
p. 2164 - 2167
(2010/06/13)
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- o-benzenedisulfonimide as a soft, efficient, and recyclable catalyst for the acylation of alcohols, phenols, and thiols under solvent-free conditions: Advantages and limitations
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o-Benzenedisulfonimide turns out to be a highly efficient Bransted acid catalyst for the acylation of a number of alcohols, phenols, and thiols under a metal- and solvent-free procedure; reaction conditions are mild and yields very good. After the workup, the catalyst can be easily recovered and purified, ready to be reused, with economic and ecological advantages. Georg Thieme Verlag Stuttgart · New York.
- Barbero, Margherita,Cadamuro, Silvano,Dughera, Stefano,Venturello, Paolo
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experimental part
p. 3625 - 3632
(2009/07/04)
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- A novel method for the synthesis of thioacetates using benzyltriethyl- ammonium tetrathiomolybdate and acetic anhydride
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Herein we report a simple and efficient methodology for the synthesis of thioacetates using benzyltriethylammonium tetrathiomolybdate and acetic anhydride as the key reagents, starting from alkyl halides in a multistep, tandem reaction process. Its application in the synthesis of orthogonally protected cysteine and anomeric β-thioglycosides has also been demonstrated.
- Nasir, Baig R. B.,Sai, Sudhir V.,Srinivasan, Chandrasekaran
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experimental part
p. 2684 - 2688
(2009/04/16)
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- Practical preparation of esters and thioacetates from alkyl halides and carboxylates or thioacetate catalyzed by PEG400 without solvent
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Carboxylic esters and thioacetates were conveniently prepared in good to excellent yields under mild conditions by the reaction of alkyl halides with sodium carboxylates or sodium thioacetate catalyzed by PEG400 in the absence of solvents. Copyright Taylor & Francis Group, LLC.
- Cao, Yu-Qing,Wu, Guo-Qiang,Li, Ya-Bin,Dai, Zhi,Chen, Bao-Hua
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p. 3353 - 3358
(2007/10/03)
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- A facile and practical method for the preparation of thioacetates from alkyl halides and sodium thioacetate catalysed by PEG400
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Thioacetates are conveniently prepared in high yields under mild conditions by the reaction of alkyl halides and sodium thioacetate, prepared in situ from thioacetic acid and sodium carbonate, catalysed by PEG400 at room temperature.
- Cao, Yu-Qing,Du, Yun-Fei,Chen, Bao-Hua,Dai, Zhi
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p. 762 - 763
(2007/10/03)
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- A Convenient Synthesis of Thioacetates and Thiobenzoates Using Silica-Gel Supported Potassium Thioacetate
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A simple and efficient procedure has been developed for the synthesis of thioesters by a reaction of alkyl halides with silica-gel supported potassium thioacetate or thiobenzoate under mild conditions.
- Aoyama, Tadashi,Takido, Toshio,Kodomari, Mitsuo
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p. 3817 - 3824
(2007/10/03)
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- Convenient synthesis of thiol esters from acyl chlorides and disulfides using Zn/AlCl3
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Various thiol esters were prepared by condensation of acyl chlorides with disulfides in the presence of Zn/AlCl3. The advantages of this method are high yields under relatively mild conditions, simple work-up, lack of toxicity, and low costs.
- Lakouraj, Moslem M.,Movassagh, Barahman,Fadaei, Zahra
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p. 1085 - 1088
(2007/10/03)
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- Conversion of 2-(trimethylsilyl)ethyl sulfides into thioesters
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Treatment of 2-(trimethylsilyl)ethyl sulfides with a carboxylic acid chloride and AgBF4 in CH2Cl2 furnishes the corresponding thioesters in high yields and purities. The conversion of 2-(trimethylsilyl)ethyl sulfides into synthetically versatile thioesters allows such sulfides to be used as sulfhydryl protective groups, since such sulfides are easily prepared and are stable towards many reaction conditions encountered in organic syntheses.
- Grundberg, Hans,Andergran, Magnus,Nilsson, Ulf J.
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p. 1811 - 1814
(2007/10/03)
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- A general and mild synthesis of thioesters and thiols from halides
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The conversion of a wide variety of halides to thioesters by reaction with potassium thiocetate under mild conditions is described, and the generality of the method is demonstrated.
- Zheng, Tu-Cai,Burkart, Maureen,Richardson, David E.
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p. 603 - 606
(2007/10/03)
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- 1-(2,5-dichlorophenyl)-2,2-bis(methylsulfanyl)vinyl esters as highly efficient chemoselective acylating reagents
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1-(2,5-Dichlorophenyl)-2,2-bis(methylsulfanyl)vinyl esters 4f-k were prepared in yields usually greater than 90%, by reacting acyl chlorides with 1-(2,5-dichlorophenyl)-2,2-bis(methylsulfanyl)ethanone enolate. These esters were demonstrated to be excellent chemoselective reagents for the acylation of amines, alcohols, thiols, pyrrole and indole. From all the acylation reactions the dimethyl α-oxo dithioacetal 2d, recyclable for the preparation of esters 4f-k, could be recovered in 90-100% yield.
- Degani,Dughera,Fochi,Serra
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p. 1200 - 1208
(2007/10/03)
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- HOMOLYTIC TRANSFORMATIONS OF 1,3-OXATHIOLANES AT HIGH PRESSURE
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The effect of high pressure was studied on the rate and direction of the homolytic transformations of 1,3-oxathiolanes.Pressure reduces the rate of the transformation of 2-methyl- and 2-isopropyl-1,3-oxathiolanes to ethyl and 2-chloroethyl thoiacylates in the presence of CCl4 to a greater extent than the initiation rate in the system.The selectivity of the formation of the reaction product which is formed more rapidly at normal pressure is increased in the competing homolytic transformations of 2-methyl- and 2-isopropyl-1,3-oxathiolanes to the corresponding ethyl thioacylates with increasing pressure.The yield of the cyclic adduct, 2-methyl-2-hexyl-1,3-oxathiolane, relative to that of linear octyl thioacetate is increased in the homolytic addition of 2-methyl-1,3-oxathiolane to 1-hexane with increasing pressure.
- Trifonova, V. N.,Zorin, V. V.,Batyrbaev, N. A.,Makarova, Z. G.,Zlotskii, S. S.,et al.
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p. 1386 - 1389
(2007/10/02)
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- STEREOSPECIFIC DISPLACEMENT OF SULFUR FROM CHIRAL CENTERS. ACTIVATION VIA THIAPHOSPHONIUM SALTS.
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The first general method for direct displacement of sulfur from chiral carbon centers has been developed.Chiral mercaptans are readily converted to the corresponding thiaphosphonium salts by treatment with t-butyl hypochlorite and hexamethylphosphorous triamide.Metathesis with ammonium hexafluorophosphate provides stable, isolable, crystalline salts which undergo clean nucleophilic diplacement with a variety of heteroatom and carbon based nucleophiles, affording products in which the stereochemistry has been inverted.
- Krafft, Grant A.,Siddall, Thomas L.
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p. 4867 - 4870
(2007/10/02)
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- HOMOLYTIC ADDITION OF 1,3-DITHIOLANES AND 1,3-OXATHIOLANES TO 1-HEXENE
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In the presence of tert-butyl peroxide at 150 deg C 1,3-dithiolane and 2-methyl-1,3-dithiolane add to 1-hexene, forming 2-hexyl-1,3-dithiolane and 2-methyl-2-hexyl-1,3-dithiolane respectively.Under these conditions 1,3-oxathiolane and 2-methyl-1,3-oxathiolane form 2-hexyl-1,3-oxathiolane and octyl thioformate and 2-methyl-2-hexyl-1,3-oxathiolane and octyl thioacetate respectively.
- Batyrbaev, N. A.,Zorin, V. V.,Zlot-skii, S. S.,Rakhmankulov, D. L.
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p. 1727 - 1729
(2007/10/02)
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