84907-79-9Relevant academic research and scientific papers
Stereospecific Synthesis of α-Deuteriated α-Amino Acids: Regiospecific Deuteriation of Chiral 3-Isopropyl-2,5-dimethoxy-3,6-dihydropyrazines
Rose, Janet E.,Leeson, Paul D.,Gani, David
, p. 157 - 166 (2007/10/02)
Base-catalysed deuteriation of (3R)- or (3S)-3-isopropyl-2,5-dimethoxy-3,6-dihydropyrazines in refluxing CH3O2H-2H2O gives the -isotopomer in excellent yields without disturbing the stereogenic centre at C-3.These compounds provide convenient and efficient access to a range of (R)- and (S)-α-deuteriated α-amino acids, including serine, aspartic acid, allylglycine and phenylalanine, via alkylation of the butyllithium generated C-6 anion.
ENANTIOSELECTIVE SYNTHESIS OF NON-PROTEINOGENIC AMINO ACIDS VIA METALLATED BIS-LACTIM ETHERS OF 2,5-DIKETOPIPERAZINES
Schoellkopf, Ulrich
, p. 2085 - 2092 (2007/10/02)
Bis-lactim ethers 1 of 2,5-diketopiperazines contain a chiral inducing center, an acidic CH-bond and two sites susceptible to hydrolysis.They react with BuLi to give Li compounds of type 4, 15, 29 or 32, which possess a prochiral C atom.They readily add electrophiles (such as alkylating agents or carbonyl compounds) with unusually high diastereoface differentiation.In many cases the d.e-value (d.e. = diastereomeric excess = asymmetric induction) of the adduct exceeds 95percent.On hydrolysis the adducts are cleaved liberating the chiral auxiliary (used to build up the bis-lactim ether 1) and the target molecules, the optically active amino acid methyl esters of type 8, 19, 25 or 36.The two amino acid esters are separable either by fractional distillation or (eventually after further hydrolysis to amino acids) by chromatography.Transition state models are discussed that could explain the exceptionally high asymmetric induction and the predictability of the induced configuration.
