- Synthesis of Amino Acids with Modified Principal Properties 3: Sulfur-Containing Amino Acids
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The synthesis and characterization of seven medium-sized, medium-polar, sulfur-containing amino acids are presented.The compounds were prepared with the objective of finding amino acids which possess physical and chemical properties such that their principal properties would be clearly different from those of previously known amino acids.The principal properties are determined as latent variables in principal component analysis of molecular property descriptors.The following amino acids were prepared in homochiral form from L-cysteine: (2R)-2-amino-3-(2-hydroxyethylsulfanyl)propanoic acid, (2R)-2-amino-3-(2-hydroxyethylsulfonyl)propanoic acid, (3R)-perhydro-1,4-thiazine-3-carboxylic acid and (3R)-1,1-dioxoperhydro-1,4-thiazine-3-carboxylic acid. (3R)-1-Oxoperhydro-1,4-thiazine-3-carboxylic acid was prepared in N,C protected form, but all attempts to obtain the free amino acid failed.The principal properties of this amino acid were determined on the racemic diastereomers obtained by oxidation of the racemic perhydro-1,4-thiazine-3-carboxylic acid prepared from 2-aminoethanethiol and ethyl 3-bromo-2-oxopropanoate.With the exception of (3R)-perhydro-1,4-thiazine-3-carboxylic acid for which the synthesis has been previously described, the amino acids described are new compounds.An improved synthesis of (3R)-perhydro-1,4-thiazine-3-carboxylic acid via the cyclization of (2R)-benzyl-2-amino-3-(2-hydroxyethylsulfanyl)propanoate under Mitsunobu conditions is presented.Full experimental details for the syntheses are given.The principal property scores of the synthesized sulfur-containing amino acids and of the structurally related 3-(2-aminoethyl)cysteine which was commercially available are given.
- Larsson, Ulf,Carlson, Rolf
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p. 517 - 525
(2007/10/02)
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