13257-30-2Relevant academic research and scientific papers
Synthesis and electrochemical behaviour of β-halodehydroamino acid derivatives
Ferreira, Paula M. T.,Monteiro,Pereira
experimental part, p. 499 - 513 (2010/11/04)
Several new β,β-dihalo and β-halo-β-substituted dehydroalanines and dehydrodipeptides were synthesized by reacting the corresponding dehydroamino acid derivative with a N-halosuccinimide or in the case of β,β-di-iododehydroalanines with iodine. The results obtained confirmed that the stereochemical outcome of the halogenation reaction with β-substituted dehydroamino acids depends on the substrate. Thus, an increase Z-stereoselectivity was found when the β-phenyldehydroalanines were used as substrates and when these compounds were N-protected with 4-tolylsulfonyl or with carbamates. From this study, it is also possible to conclude that when N-iodosuccinimide was used as reagent a much higher Z-stereoselectivity is found. The electrochemical behaviour of the halogenated dehydroamino acids was studied by cyclic voltammetry. The results show a shift in the reduction peak to higher potentials of the β-halogenated dehydroamino acids when compared with the corresponding non-halogenated derivatives. As expected, the β,β-dihalodehydroalanines exhibit higher peak potentials than β-halo-β-substituted dehydroalanines and the bromo derivatives have lower peak potentials when compared with the corresponding iododehydroamino acids. Controlled potential electrolysis of several β-halo-β-substituted dehydroamino acids afforded the corresponding dehalogenated dehydroamino acids as mixtures of their E and Z-isomers. In all cases, the major isomer isolated results from dehalogenation without isomerization. These new results show that electrochemical reduction constitutes a valuable method for the synthesis of the E-isomer of β-substituted dehydroalanines. Springer-Verlag 2010.
N-Acyl-α-triphenylphosphonioglycinates in the synthesis of α,β-dehydro-α-amino acid derivatives
Mazurkiewicz, Roman,Kuznik, Anna,Grymel, Miroslawa,Kuznik, Nikodem
, p. 807 - 815 (2007/10/03)
N-Acyl-α-triphenylphosphonioglycinates when treated with triethylamine are transformed to an equilibrium mixture of the corresponding N-acyliminoacetates and N-acyl-α-triphenylphosphoranylideneglycinates. Wittig reaction of the latter ylides with aromatic and aliphatic aldehydes or ketones enables a new easy entry to N-acyl-α,β-dehydro-α-amino acid esters. Springer-Verlag 2004.
Selective and Convenient Enzymatic Separation of Geometric Isomers of N-Protected-α-dehydrophenylalanine Esters
Shin, Chung-gi,Seki, Masashi
, p. 887 - 888 (2007/10/02)
Selective enzymatic hydrolysis of a mixture of (Z)- and (E)-N-protected-ΔPhe-OMe with α-chymotrypsin A took place to give (Z)-ΔPhe-OH and (E)-ΔPhe-OMe
N-Acyl Dehydro-α-amino Acids from N-Formyl Dehydro-α-amino Acid Esters
Schoellkopf, Ulrich,Meyer, Rolf
, p. 1469 - 1475 (2007/10/02)
On treatment with methyl potassioisocyanoacetate (2), aldehydes and ketones 1 give N-anionized N-formyl dehydro-α-amino acid methyl esters 3.Compounds 3 with R1 = CH3, R2 = H is obtained by base induced ring opening of methyl 2-oxazoline-4-carboxylate 5. - Acylation of 3, followed by deformation of the intermediates 6, yields N-acyl dehydro α-amino acid methyl esters 7 which can be hydrolyzed to the N-acyl dehydro α-amino-acids 8.
