26924-22-1Relevant academic research and scientific papers
Amino Acids, 16. - Synthesis of N-Acyl-2,3-didehydro-2-amino Acid Esters
Effenberger, Franz,Kuehlwein, Juergen,Drauz, Karlheinz
, p. 1295 - 1302 (2007/10/02)
N-Acyl-2,3-didehydro-2-amino acid esters 3, 5, 7-12, with a great variety of N-substituents, are obtained in good yields by the perrhenate-catalyzed decomposition of methyl 2-azido carboxylates 1 in organic solvents in the presence of the corresponding acyl chlorides 2.By using methyl 2-azido-isovalerate (1a), the conditions (catalyst, solvent, temperature) for the reaction to give 3a were optimized.The reactivity of acyl chlorides can be strongly enhanced with equimolar amounts of dimethyl formamide, which allows a lowering of the decomposition temperature for this reaction.Under these mild reaction conditions also the unstable N-acyldehydroalanine derivative 5f can be obtained in good yield. - Key Words: 2-Azidocarboxylates/ Rhenium catalysts/ Amino acids
Reaction of N-Benzoyl-2-bromoglycine Methyl Ester with Deprotonated Nitroalkanes: Synthesis of β-Nitro and α,β-Dehydro Amino Acid Derivatives
Burgess, Vicky A.,Easton, Christopher J.
, p. 1063 - 1070 (2007/10/02)
N-Benzoyl-2-bromoglycine methyl ester (1) reacted with the alkyl nitronates (2a-e) to give the corresponding β-nitro amino acid derivatives (4a-e).Elimination reactions of (4a-d) afforded the α,β-dehydro amino acid derivatives (5a-d).Treatment of the β-nitrovaline derivative (4b) with tributyltin hydride gave the valine derivative (8).Reduction of the β-nitroalanine derivative (4a) gave the β-aminoalanine derivative (9), characterized by hydrolysis to 2,3-diaminopropionic acid hydrochloride
REGIOSELECTIVE FORMATION OF AMIDOCARBOXY-SUBSTITUTED FREE RADICALS
Easton, Christopher J.,Hay, Michael P.,Love, Stephen G.
, p. 265 - 268 (2007/10/02)
Factors affecting the production of amidocarboxy-substituted free radicals have been investigated by examining reactions of derivatives of valine and sarcosine.Variations in the regioselectivity of reactions of these compounds are exemplified by the reactions of N-benzoylvaline methyl ester (4a) and N-benzoylsarcosine methyl ester (12a) with sulphuryl chloride and N-bromosuccinimide.Whereas the reaction of (4a) with sulphuryl chloride involves hydrogen-atom transfer from the β-position of (4a) with subsequent chlorine incorporation to give (4g), in direct contrast the reaction with N-bromosuccinimide proceeds via hydrogen-atom abstraction from the α-position of (4a) and yields the dibromide (4d).N-benzoylsarcosine methyl ester (12a), reacts with N-bromosuccinimide to give the α-bromosarcosine derivative (12b), whereas with sulphuryl chloride the product is the N-chloromethylglycine derivative (12c).These studies indicate that amidocarboxy-substituted radicals such as (3a) and (13) are considerably more stable than the tertiary alkyl radical (1a) and the amidosubstituted radical (14), respectively, but hydrogen-atom transfer reactions may afford the less stable products if electrophilic radicals are involved in the hydrogen-atom abstraction and if there is little development of radical character in the reaction transition state.
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.
