共查询到20条相似文献,搜索用时 15 毫秒
1.
M. Moghadam S. Tangestaninejad V. Mirkhani I. Mohammadpoor-Baltork M. Babaghanbari M. Zarea L. Shariati S. A. Taghavi 《Journal of the Iranian Chemical Society》2009,6(3):523-532
Highly efficient acetylation and benzoylation of alcohols, phenols, amines and thiols with acetic and benzoic anhydrides catalyzed by new and reusable zirconyl triflate, ZrO(OTf)2, is reported. The high catalytic activity of electron deficient ZrO(OTf)2 can be used for the acetylation and benzoylation of not only primary alcohols but also sterically-hindered secondary and tertiary alcohols with acetic and benzoic anhydrides. Acetylation of phenols with acetic and benzoic anhydrides was achieved to afford the desired acetates and benzoates efficiently. This catalyst also efficiently catalyzed the acetylation and benzoylation of amines and thiols whereby the corresponding amides and thioesters were obtained in good to excellent yields. This catalyst can be reused several times without loss of its activity. 相似文献
2.
Fluoroboric acid supported on silica gel efficiently catalyzes acylation of structurally diverse phenols, alcohols, thiols, and amines under solvent free conditions. Acid-sensitive alcohols are smoothly acylated without competitive side reactions. 相似文献
3.
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. 相似文献
4.
Air-stable titanocene bis(perfluorooctanesulfonate) [Cp2Ti(OSO2C8F17)2] that shows high Lewis acidity was prepared from Cp2TiCl2 and AgOSO2C8F17. The compound was characterized by different techniques, and examined as a catalyst for acylation reactions. It was found that using equimolar acetic anhydride as acetylating agent and under solvent-free condition, Cp2Ti(OSO2C8F17)2 exhibits high activity and selectivity in the acetylation of various alcohols, phenols, thiols, and amines. Also, good catalytic efficiency is observed in the acylation of 2-phenylethanol across various acylating reagents. The catalyst can be reused without loss of activity in a test of ten cycles. The Cp2Ti(OSO2C8F17)2 catalyst affords a simple, efficient and general method for the acylation of alcohols, phenols, thiols, and amines. 相似文献
5.
Indium(III) chloride efficiently catalyses the acylation of structurally diverse phenols, alcohols, thiols, and amines under solvent free conditions. Acid sensitive alcohols are smoothly acylated without competitive side reactions. Acylation of 2-hydroxynaphthalene is carried out with carboxylic acids adopting the mixed anhydride protocol using trifluoroacetic anhydride. 相似文献
6.
Perchloric acid adsorbed on silica gel efficiently catalyses acetylation of structurally diverse phenols, alcohols, thiols, and amines under solvent free conditions. 相似文献
7.
Surya Kanta De 《Tetrahedron letters》2004,45(14):2919-2922
Ruthenium(III) chloride catalyzes the acylation of a variety of phenols, alcohols, thiols, and amines under mild conditions. Some of the major advantages of this method are high yields, short reaction times, ease of operation, and compatibility with other protecting groups. 相似文献
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9.
Zinc oxide (ZnO) is a highly efficient catalyst for the acylation of a variety of alcohols, phenols and amines with acid chlorides or acid anhydrides under solvent free conditions. Primary, secondary, tertiary, allylic and benzylic alcohols, diols and phenols with electron donating or withdrawing substituents can be easily acylated in good to excellent yield. 相似文献
10.
《Tetrahedron letters》2003,44(34):6369-6373
The conjugate addition of aliphatic and aromatic thiols to ethynyl p-tolyl sulphone (tosylacetylene) has been managed to afford Tosvinyl derivatives chemoselectively (in the presence of oxygen nucleophiles) and stereoselectively (isomers Z) in practically quantitative yields. The conditions of choice are: catalytic amounts of Et3N (only 0.5-1.0 mol%), a reaction temperature around 0°C and, for the less acidic thiols, CF3CH2OH or CH3CN/CF3CH2OH as the solvent. Thus, N-Boc-Cys-OMe has been quantitatively protected as its S-Tosvinyl derivative in the presence of N-Boc-Ser-OMe and N-Boc-Tyr-OMe. This novel protecting group is stable to several basic and acidic conditions; its removal is achieved at rt by treatment with an excess of pyrrolidine or at 0°C with alkanethiolate ions. 相似文献
11.
Thiols react with dichloromaleimides in the presence of base to give 2,3-bis[alkyl(aryl)-mercapto]maleimides. Alcohols and phenols in equivalent amounts give 2-alkyl(aryl)oxy-3-chloromaleimides. With two equivalents, phenols give 2,3-bis(aryloxy)maleimides, but alcohols give 2-chloro-3,3-dialkoxysuccinimides in protic solvents and dimeric compounds in aprotic solvents. 相似文献
12.
The 8-hydroxyquinolate of pentavalent vanadium (“vanadium 8-hydroxyquinolate”, (C9H6ON)2. VO.OH) dissolves in a number of chlorohydrocarbons to give deep blue-black solutions. These solutions undergo distinctive colour changes upon addition of acids (blue), alcohols (red via purple), thiols (yellow via green) and amines (yellow via green), provided that these reagents are soluble in the chlorohydrocarbon. These sensitive and specific qualitative tests are extended to the semiquantitative determination of alcohols. For comparable compounds the rate of reaction with vanadium 8-hydroxyquinolate is as follows: [—NH2, NH, N] > [—CH2OH,—CH2SH] > [CHOH, CHSH] > [COH, CSH]. 相似文献
13.
A novel and efficient method for the N-formylation of amines via the reaction of orthoformates and amines is developed. The reactions are mediated by a catalytic amount of molybdate sulfuric acid as a heterogeneous solid acid. 相似文献
14.
Farhad Shirini Meysam Alipour Khoshdel Masoumeh Abedini Seyyed Vahid Atghia 《中国化学快报》2011,22(10):1211-1214
Nanocrystalline TiO2 was used as an efficient and recyclable catalyst for the chemoselective trimethylsilylation of primary and less hindered secondary alcohols and phenols with hexamethyldisilazane(HMDS).All reactions were performed under mild and completely heterogeneous conditions in good to excellent yields. 相似文献
15.
Poly(4-vinylpyridine) (PVP) acts as an efficient and reusable catalyst for the selective and efficient trimethylsilylation of alcohols and phenols with hexamethyldisilazane (HMDS) and N-tert-butoxycarbonylation of amines with (Boc)2O. All reactions were performed under mild conditions in good to high yields. 相似文献
16.
Bikash Karmakar 《Tetrahedron letters》2010,51(29):3855-3858
An efficient, chemoselective and eco-friendly protocol for the protection of amines as N-tert-butylcarbamate using (Boc)2O and protection of alcohols as silyl ether using HMDS over tungstophosphoric acid/SBA15 has been developed. Solventless condition, easy work-up, short reaction time, excellent yields and reusability of the catalyst are the striking features of this methodology which can be considered to be one of the better methods for the protection of amines and alcohols. 相似文献
17.
Some selected results of recent studies of alcohols, amines and thiols are reviewed and discussed. 相似文献
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19.
Fatemeh Rajabi 《Tetrahedron letters》2009,50(4):395-164
Acetylation of various alcohols and phenols was performed successfully using an immobilized cobalt(II) catalyst in high yield. The catalyst shows high thermal stability and was also recovered and reused at least 10 times without any considerable loss of activity. 相似文献
20.
Naseem Ahmed 《Tetrahedron letters》2006,47(30):5345-5349
Iodine in isopropenyl acetate (IPA) is a highly efficient catalyst for the acetylation of a variety of alcohols, phenols and amines under solvent free conditions. Primary, secondary, tertiary alcohols, amines and mono to polyhydroxy phenols and anilines with electron donating or withdrawing substituents can be easily acetylated in good to excellent yield at 85-90 °C. 相似文献