- Synthesis of enantiopure α-deuteriated Boc-L-amino acids
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An alternative scheme for the synthesis of enantiopure α-deuteriated amino acids from a common intermediate is presented. Methyl bis(methylsulfanyl)methylene[2,2-2H2]glycinate was prepared in a mixture of MeOD and D2O with a catalytic amount of Na2CO3 and attached to (2R)-bornane-10,2-sultam. Alkylation of the corresponding enolate provided intermediates which after careful purification were first deprotected on nitrogen and then cleaved from the auxiliary to give deuteriated α-amino acids of very high purity (> 99% ee and > 98% D). These were directly converted into the corresponding Boc-L-[2-2H]-Ala, -Leu, -Phe and -(O-Bzl)Tyr derivatives, suitable for application in peptide synthesis. Boc-[2,2-2H2]Gly was also prepared.
- Elemes, Yiannis,Ragnarsson, Ulf
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- Solution-Phase Raman Studies of Alanyl Dipeptides and Various Isotopomers: A Reevaluation of the Amide III Vibrational Assignment
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Solution-phase Raman spectra of L-alanyl-L-alanine and five nitrogen and/or α-deuterated isotopomers are reported.Detailed vibrational assignments on this set of spectra have led to a somewhat different interpretation of the amide III vibrational region, as compared to literature assignments.The differences result from the fact that, in these deuterated samples, the nature of certain vibrations, and their interactions with other vibrations of similar energies, may be investigated with very high sensitivity.A discussion of the observed interaction of the amide III vibration and the methine deformation is presented, leading to an explanation for the geometric sensitivity of the band commonly referred to as the "amide III" mode.
- Oboodi, M. Reza,Alva, Carlos,Diem, Max
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p. 501 - 505
(2007/10/02)
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