- Synthesis of arylglycine and mandelic acid derivatives through carboxylations of α-amido and α-acetoxy stannanes with carbon dioxide
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Incorporation reactions of carbon dioxide (CO2) with N-Boc-α-amido and α-acetoxy stannanes were developed using CsF as a mild tin activator. Monoprotected α-amido stannanes could be used, and the corresponding arylglycine derivatives were obtained in moderate-to-high yields under 1 MPa (10 atm) of CO2 pressure. α-Acetoxy stannanes also underwent carboxylation to afford mandelic acid derivatives in excellent yields under ambient CO2 pressure. Both transformations enabled the synthesis of α-tertiary and α-quaternary carboxylic acid derivatives. In addition, the chirality of (S)-N-tert-butylsulfonyl-α- amido stannanes was transferred with up to 90% inversion of configuration at 100 °C.
- Mita, Tsuyoshi,Sugawara, Masumi,Hasegawa, Hiroyuki,Sato, Yoshihiro
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experimental part
p. 2159 - 2168
(2012/06/01)
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- Synthesis, anticonvulsant activity, and neuropathic pain-attenuating activity of N-benzyl 2-amino-2-(hetero)aromatic acetamides
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N-Benzyl 2-acetamido-2-substituted acetamides, where the 2-substituent is a (hetero)aromatic moiety, are potent anticonvulsants. We report the synthesis and whole animal pharmacological evaluation of 16 analogues where the terminal 2-acetyl group was removed to give the corresponding primary amino acid derivatives (PAADs). Conversion to the PAAD structure led to a substantial drop in seizure protection in animal tests, demonstrating the importance of the N-acetyl moiety for anticonvulsant activity. However, several of the PAADs displayed notable pain-attenuating activities in a mouse model.
- Baruah, Pranjal K.,Dinsmore, Jason,King, Amber M.,Salomé, Christophe,De Ryck, Marc,Kaminski, Rafal,Provins, Laurent,Kohn, Harold
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p. 3551 - 3564
(2012/07/28)
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- One-pot synthesis of α-amino acids from imines through CO2 incorporation: An alternative method for strecker synthesis
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Itas a gas: A novel one-pot process for the synthesis of α-amino acids from imine equivalents using CO2 gas as a carbon source has been developed. This reaction was made possible by the reagent combination of TMSSnBu3 and CsF (see scheme). Three successive reactions (imine formation, stannylation, and carboxylation) proceeded in the same flask under these conditions to give products in up to 79 % yield. Boc=tert-butoxycarbonyl, TMS=trimethylsilyl.
- Mita, Tsuyoshi,Chen, Jianyang,Sugawara, Masumi,Sato, Yoshihiro
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p. 1393 - 1396
(2011/04/22)
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- Highly selective tripeptide thrombin inhibitors
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Tripeptide aldehydes such as Boc-D-Phe-Pro-Arg-H (5l) exhibit potent direct inhibition of thrombin. This distinction offers important insight for the design of more potent and selective serine protease inhibitors which may be useful pharmacological tools and hold promise for development of clinically useful agents. The structure-activity relationships (SAR) on a series of anticoagulant peptides with high selectivity for the enzyme thrombin are discussed. The SAR is centered on a series of di- and tripeptide arginine aldehydes based on the structure of 5l. The structural and conformational role of the amino acid residue in position 1 was investigated by substitution with conformationally restricted aromatic amino acids, aromatic acids, and a dipeptide isostere containing the ψ[CH2N] amide bond replacement. Many of these peptides demonstrate potent antithrombotic activity along with selectivity toward thrombin, determined by comparison of in vitro inhibitory effects on trypsin, plasmin, factor Xa, and tissue plasminogen activator. Compound 5f, D-1-Tiq-Pro-Arg-H · sulfate is highly active and the most selective tripeptide aldehyde inhibitor of thrombin reported to date.
- Shuman,Rothenberger,Campbell,Smith,Gifford-Moore,Gesellchen
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p. 314 - 319
(2007/10/02)
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