- Staudinger/aza-Wittig reaction to access Nβ-protected amino alkyl isothiocyanates
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A unified approach to access Nβ-protected amino alkyl isothiocyanates using Nβ-protected amino alkyl azides through a general strategy of Staudinger/aza-Wittig reaction is described. The type of protocol used to access isothiocyanates depends on the availability of precursors and also, especially in the amino acid chemistry, on the behavior of other labile groups towards the reagents used in the protocols; fortunately, we were not concerned about both these factors as precursor-azides were prepared easily by standard protocols, and the present protocol can pave the way for accessing title compounds without affecting Boc, Cbz and Fmoc protecting groups, and benzyl and tertiary butyl groups in the side chains. The present strategy eliminates the need for the use of amines to obtain title compounds and thus, this method is step-economical; additional advantages include retention of chirality, convenient handling and easy purification. A few hitherto unreported compounds were also prepared, and all final compounds were completely characterized by IR, mass, optical rotation, and 1H and 13C NMR studies.
- Santhosh,Durgamma,Shekharappa,Sureshbabu, Vommina V.
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p. 4874 - 4880
(2018/07/15)
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- Synthesis of Nα-Z protected amino alkyl triazole acids and their application to neo-glycopeptides synthesis
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The synthesis of triazole linked glycopeptides employing 2-chloro-4,6-dimethoxy-1,3,5-triazine (CDMT) mediated coupling of Z-protected triazole acids with glycosyl amines and amino acid esters is described. The coupling proceeded smoothly at room temperat
- Madhu, Chilakapati,Panguluri, Nageswara Rao,Sureshbabu, Vommina V.
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p. 858 - 864
(2014/08/05)
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- Hydrodehalogenation of alkyl iodides with base-mediated hydrogenation and catalytic transfer hydrogenation: Application to the asymmetric synthesis of N-protected α-methylamines
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We report a very mild synthesis of N-protected α-methylamines from the corresponding amino acids. Carboxyl groups of amino acids are reduced to iodomethyl groups via hydroxymethyl intermediates. Reductive deiodination to methyl groups is achieved by hydrogenation or catalytic transfer hydrogenation under alkaline conditions. Basic hydrodehalogenation is selective for the iodomethyl group over hydrogenolysis-labile protecting groups, such as benzyloxycarbonyl, benzyl ester, benzyl ether, and 9-fluorenyloxymethyl, thus allowing the conversion of virtually any protected amino acid into the corresponding N-protected α-methylamine.
- Mandal, Pijus K.,Birtwistle, J. Sanderson,McMurray, John S.
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p. 8422 - 8427
(2015/03/18)
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- Synthesis of thioureido-linked peptidomimetics, glycosylated amino acids, and neoglycoconjugates using bis(benzotriazolyl)methanethione as thioacylating agent
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A practical synthesis of thiourea-linked peptidomimetics, glycosylated amino acids, and neoglycoconjugates is described employing bis(benzotriazolyl) methanethione as thiocarbonylating reagent. The entire protocol is mild, efficient, high-yielding, and free from hazardous reagents. All the intermediates and products have been isolated and fully characterized by 1H NMR, 13C NMR, and mass spectrometry. Georg Thieme Verlag Stuttgart ? New York.
- Sureshbabu, Vommina V.,Chennakrishnareddy, Gundala,Hemantha, Hosahalli P.
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p. 715 - 720
(2010/06/14)
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- Synthesis of Hybrid Peptidomimetics and Neoglycoconjugates Employing Click Protocol: Dual utility of Poc-group for inserting carbamate-triazole units into peptide backbone
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Synthesis of new types of peptidomimetics and glycosylated amino acids possessing 1,2,3-triazole and carbamate moieties is described. Poc-protected amino acid esters/1-amino sugars were subjected to Cu(I) catalyzed [2+3]cycloaddition with desired azides u
- Hemantha, Hosahalli P.,Lamani, Ravi S.,Sureshbabu, Vommina V.
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p. 267 - 275
(2011/10/04)
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