- 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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- Efficient synthesis of fused 1,2,3-triazolo-δ-lactams using Huisgen [3 + 2] dipolar cycloaddition "click-chemistry" in water
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A general approach for the quick synthesis of various 1,2,3-triazolo- δ-lactams has been described, which involves the Huisgen [3 + 2] dipolar cycloaddition of azides derived from different amino acids with dimethyl acetylenedicarboxylate in water followe
- Kumar, Indresh,Rode, Chandrashekhar V.
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p. 592 - 593
(2008/02/07)
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- New pyrrole-based amino acids for the synthesis of peptidomimetic constrained scaffolds
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A new family of pyrrole-based amino acids have been prepared through the microwave assisted Paal-Knorr reaction of 1-4 ketoesters derived from the corresponding β-ketoester with a functional homologation. The carboxylic group is located in position 3 of the pyrrole, whereas the amino group, protected with the Cbz moiety, is present on the side chain in positions 1 or 2. These compounds were used to prepare constrained oligopeptides.
- Alongi, Maddalena,Minetto, Giacomo,Taddei, Maurizio
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p. 7069 - 7072
(2007/10/03)
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- 2-6-diaminopurine precursors
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The present invention relates to compounds of formula (IV): STR1 wherein Ra and Rb each represent a hydrogen atom or together form an alkylidene group.
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- Modified Amino Acids and Peptides. Part 2. A Convenient Conversion of Amino and Peptide Alcohols into Amines.
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A convenient general method for the conversion of N-protected amino and peptide alcohols into amines is described.The hydroxyl group of the alcohols was replaced by an azido group and a substituted amino group after activation through mesylation.Hydrogenation of the N-protected amino azides afforded optically active monoprotected diamines or free 1,2-diamines depending on the N-protecting group.Selective reduction of the azido group in the presence of a benzyloxycarbonyl group was performed in high yield using sodium borohydride in the presence of 10percent palladium on charcoal.
- Kokotos, George,Constantinou-Kokotou, Violetta
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p. 3117 - 3132
(2007/10/02)
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