- Merrifield MicroTube(TM) reactors for solid phase synthesis
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Polystyrene grafted polypropylene MicroTube(TM) reactors (length x OD, 25 x 5 mm) have been functionalized with chloromethyl groups (Merrifield- type) using chloromethyl methyl ether and Lewis acid catalysts. A potentiometric method using a chloride ion selective electrode has been developed to measure the loading of the Merrifield MicroTube(TM) reactors. A typical loading of 25-35 μmol/tube for Merrifield MicroTube(TM) reactors has been achieved. Several reactions performed on Merrifield MicroTube(TM) reactors demonstrated that they are excellent supports for solid phase synthesis. As a result of the ease with which radiofrequency memory tags can be associated with and separated from the supports, these MicroTube(TM) reactors can facilitate the synthesis of combinatorial libraries.
- Li, Rongshi,Xiao, Xiao-Yi,Czarnik, Anthony W.
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Read Online
- A CO2-mediated base catalysis approach for the hydration of triple bonds in ionic liquids
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Herein, we report a CO2-mediated base catalysis approach for the activation of triple bonds in ionic liquids (ILs) with anions that can chemically capture CO2 (e.g., azolate, phenolate, and acetate), which can achieve hydration of triple bonds to carbonyl chemicals. It is discovered that the anion-complexed CO2 could abstract one proton from proton resources (e.g., IL cation) and transfer it to the CN or CC bonds via a six-membered ring transition state, thus realizing their hydration. In particular, tetrabutylphosphonium 2-hydroxypyridine shows high efficiency for hydration of nitriles and CC bond-containing compounds under a CO2 atmosphere, affording a series of carbonyl compounds in excellent yields. This catalytic protocol is simple, green, and highly efficient and opens a new way to access carbonyl compounds via triple bond hydration under mild and metal-free conditions.
- Han, Buxing,Ke, Zhengang,Li, Ruipeng,Liu, Zhimin,Tang, Minhao,Wang, Yuepeng,Zeng, Wei,Zhang, Fengtao,Zhao, Yanfei
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supporting information
p. 9870 - 9875
(2021/12/27)
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- Studies and synthesis of substituted 4-biphenyl acetamide derivatives
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A new series of substituted 4-biphenylamides have been synthesized by condensation of 4-biphenyl acetic acid with different primary amines (aromatic and aliphatic). 4-Biphenyl acetic acid was first treated with thionyl chloride in dry benzene to prepare substituted 4-biphenyl acetyl chloride, which is then treated with different aliphatic or aromatic amines to synthesize various substituted 4-biphenyl acid-amide derivatives. The structure of newly synthesized compounds has been established by analytical and spectral methods. These synthesized compounds have shown antifungal properties against Fusarium udum and Curvularia lunata.
- Khullar, Anju
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p. 510 - 514
(2019/02/06)
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- The actual active species of sulfur-modified gold-supported palladium as a highly effective palladium reservoir in the suzuki-miyaura coupling
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The actual active species of the recently developed sulfur-modified, gold-supported palladium material, S-modified Au-supported Pd (SAPd), with one of the lowest Pd-releasing levels and high recyclability in the Suzuki-Miyaura coupling, was investigated. Also, SAPd was found to work repeatedly as an excellent Pd reservoir for liquid-phase combinatorial synthesis. Copyright
- Hoshiya, Naoyuki,Shuto, Satoshi,Arisawa, Mitsuhiro
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supporting information; experimental part
p. 743 - 748
(2011/05/06)
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- An improved synthesis of the selective matrix metalloproteinase inhibitor, Ro 28-2653
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An efficient synthesis of Ro 28-2653, a selective matrix metalloproteinase inhibitor, has been developed. The title compound was prepared in four steps and 76% overall yield from 4-biphenylacetic acid. The key, barbituric acid formation step was significantly improved by using 2-propanol and potassium tert-butoxide as the solvent and base, respectively, instead of the typical ethanol and sodium ethoxide combination.
- Daniewski, Andrzej R.,Liu, Wen,Okabe, Masami
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p. 411 - 414
(2013/09/05)
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- Revolutionizing resin handling for combinatorial synthesis
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A new resin support generated by co-sintering resin beads with an inert polymer (see picture) facilitates resin handling. A wide range of reactions was carried out to demonstrate its applicability and its comparability to the free resin.
- Atrash, Butrus
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p. 938 - 941
(2007/10/03)
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- Effects of amino acids on the amidation of polyaromatic carboxylic acids by Bacillus cereus.
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The soil bacterium Bacillus cereus Tim-r01 efficiently transformed polyaromatic carboxylic acids (PACA) such as 4-biphenylcarboxylic acid (4-BPCA), 4-biphenylacetic acid, and 4-phenoxybenzoic acid into their corresponding amides. The amidation activity was expressed at 37 degrees C (pH 7-8) in the presence of grown cells in nutrients under an aerobic atmosphere. Other strains of B. cereus, IFO 3001 and IAM 1229, also gave the amide from 4-BPCA. In phosphate-buffered saline (PBS), the addition of normal amino acids was essential, while sulfur-containing amino acids such as methionine and cysteine drastically inhibited the amidation. Tracer experiments using N-15-isoleucine and N-15-alanine showed that the nitrogen atom of the amide came from an amino group of amino acids but not from ammonia or alkylamines.
- Maruyama,Kawata,Ono,Nishizawa,Ito,Inoue
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p. 1761 - 1765
(2007/10/03)
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- Amidation of polyaromatic carboxylic acids in aqueous medium
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The amidation of polyaromatic carboxylic acids, such as 4- biphenylcarboxylic acid, 4-biphenylacetic acid, 4-carboxy-4'-hydroxybiphenyl, and N-phenylanthranilic acid, was satisfactorily carried out to give the corresponding amides using a wild-type bacter
- Maruyama, Reiji,Ono, Shin,Inoue, Masami
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p. 5229 - 5232
(2007/10/03)
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- Solid-Phase Synthesis of Biaryls via the Stille Reaction
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The solid-phase synthesis of biphenyls by heterogenous cross-coupling of trialkylphenylstannanes with aryl electrophiles is described.Tributylphenyltin attached by an amide bond to the Rink amide resin undergoes palladium-catalyzed coupling with aryl triflates and aryl iodides to produce after acid cleavage 4-biphenylacetamide in 3-15percent yield. 4-Iodophenylacetic acid attached to the Rink amide resin by an amide bond also undergoes heterogeneous palladium-catalyzed coupling with trialkylphenyltins to give after acid cleavage of the support 4-biphenylacetamide in 21-33percent yield. 4-Iodobenzylbromide was then attached to the photocleavable (+/-)-2-methoxy-5--1-oxopropyl>phenylacetamide (NpSSMpact) resin through the formation of a thioether bond.Both substituted and unsubstituted trimethylphenyltins were shown to undergo palladium-catalyzed Stille coupling with the resin bound aryl iodide to give after photolytic cleavage biphenyls containing no residual amide, carboxylic acid, or alcohol appendages.
- Forman, Frank W.,Sucholeiki, Irving
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p. 523 - 528
(2007/10/02)
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