62735-59-5Relevant academic research and scientific papers
Simple synthesis of amides and weinreb amides Using PPh3 or PolymerSupported PPh3 and Iodine
Kumar, Amit,Akula, Hari Kiran,Lakshman, Mahesh K.
experimental part, p. 2709 - 2715 (2010/08/05)
The combination of PPh3/I2 has been shown to be effective for the conversion of a range of carboxylic acids into secondary, tertiary, and Weinreb amides. Simplification of the procedure was possible with the use of polymer-supported PPh3/ I2. Weinreb amides produced with the use of polymer-supported PPh3 could be filtered through a short silica gel plug and used in further transformations. Thus, the use of polymer-supported PPh3 offers potential applicability to diversityoriented reactions. Formal total syntheses of apocynin and pratosine, as well as syntheses of anhydrolychorinone and hippadine, have been achieved through the use of this amide-forming method. An attempt has been made to gain insight into this reaction.
New boron(III)-catalyzed amide and ester condensation reactions
Maki, Toshikatsu,Ishihara, Kazuaki,Yamamoto, Hisashi
, p. 8645 - 8657 (2008/02/08)
In 1996, we reported that benzeneboronic acids bearing electron-withdrawing groups at the meta- or para-position are highly effective catalysts for the amide condensation reaction in less-polar solvents. In this paper, we report that N-alkyl-4-boronopyridinium halides are more effective catalysts than the previous ones in more polar solvents. N-Alkyl-4-boronopyridinium halides are effective not only for amide condensation between equimolar mixtures of carboxylic acids and amines but also for the esterification of α-hydroxycarboxylic acids in alcohol solvents. Furthermore, perchlorocatecholborane is more effective than areneboronic acids for the amide condensation of sterically demanding carboxylic acids. In addition, Lewis acid-assisted Br?nsted acid (LBA), which is prepared from a 1:2 M mixture of boric acid and tetrachlorocatechol, is effective for the Ritter reaction from alcohols and nitriles to amides.
N-alkyl-4-boronopyridinium salts as thermally stable and reusable amide condensation catalysts
Maki, Toshikatsu,Ishihara, Kazuaki,Yamamoto, Hisashi
, p. 5043 - 5046 (2007/10/03)
(Chemical Equation Presented) N-Alkyl-4-boronopyridinium salts are highly effective and reusable catalysts for the dehydrative amide condensation reaction between equimolar mixtures of carboxylic acids and amines. N- Alkylboronopyridinium salts are thermally stabilized in the order N-alkyl-2-boronopyridinium salt ? N-alkyl-3-boronopyridinium salt N-alkyl-4-boronopyridinium salt. Homogeneous catalysts, such as 4-borono-N-methylpyridinium iodide, are more effective in the presence of ionic liquid and can be recovered by extraction with ionic liquid. In contrast, heterogeneous catalysts, such as polystyrene-bound 4-boronopyridinium salts, are effective even in the absence of ionic liquid and can be recovered by filtration.
The anticonvulsant activities of functionalized N-benzyl 2-acetamidoacetamides. The importance of the 2-acetamido substituent
Choi, Daeock,Stables, James P.,Kohn, Harold
, p. 2105 - 2114 (2007/10/03)
Recent studies have demonstrated that substituted N-benzyl 2-acetamidoacetamides provide significant protection against maximal electroshock (MES)-induced seizures in mice and rats. In this study, we investigated whether the 2-acetamido moiety was necessary for anticonvulsant activity. Ten derivatives of the known anticonvulsant, N-benzyl 2-acetamido-2-phenylacetamide were prepared in which the 2-acetamido group was replaced by hydrogen, methyl, oxygen, and halogen substituents. Evaluation of these compounds in the MES-induced seizure test demonstrated that both the hydroxy and the methoxy compounds provided full protection against MES-induced seizures in mice given ip at 100 mg/g. Moreover, evaluation of the individual stereoisomers for the hydroxy compound showed that the principal activity resided in the (R)-isomer. These findings demonstrated that the 2-acetamido substituent is important but not obligatory for the prevention of MES-induced seizures. Further supporting evidence was provided by comparing the pharmacological activities of N-benzyl 2,3-dimethoxypropionamide with N-benzyl 2-acetamido-3-methoxypropionamide. The ED50 value for the former in the MES test was 3.0 mg/kg (ip), which compared favorably with phenobarbital (ED50=22 mg/kg), but the ED50 value for N-benzyl 2-acetamido-3-methoxypropionamide was 8.3 mg/kg.
