Asymmetric synthesis of β2-amino acids: 2-substituted-3-aminopropanoic acids from N-acryloyl SuperQuat derivatives
作者:James E. Beddow、Stephen G. Davies、Kenneth B. Ling、Paul M. Roberts、Angela J. Russell、Andrew D. Smith、James E. Thomson
DOI:10.1039/b707689d
日期:——
Conjugateaddition of lithium dibenzylamide to (S)-N(3)-acryloyl-4-isopropyl-5,5-dimethyloxazolidin-2-one (derivedfrom l-valine) and alkylation of the resultant lithium beta-amino enolate provides, after deprotection, a range of (S)-2-alkyl-3-aminopropanoic acids in good yield and high ee. Alternatively, via a complementary pathway, conjugateaddition of a range of secondary lithium amides to (S)
β2-Homo-Amino Acid Scan of µ-Selective Opioid Tetrapeptide TAPP
作者:Dagmara Tymecka、Piotr F. J. Lipiński、Piotr Kosson、Aleksandra Misicka
DOI:10.3390/molecules25102461
日期:——
included compounds in which a (R)- or (S)-β2-Homo-Homologue replaced the amino acids in the TAPP sequence. The derivatives with (R)- or (S)-β2hPhe4 turned out to bind µOR with affinities equal to that of the parent. β2hAAs in position 1 and 3 resulted in rather large affinity decreases, but the change differed depending on the stereochemistry. β2-Homologation in the second position gave derivatives with very
Enantioselective synthesis of β-amino acids. 7. Preparation of enantiopure α-substituted β-amino acids from 1-benzoyl-2(S)-tert-butyl-3-methylperhydropyrimidin-4-one.1,2
Inexpensive natural α-amino acid L-asparagine was efficiently converted to either (R)- or (S)-α-alkylated β-amino acids in enantiomerically pure state. The key intermediate in this protocol is the enantiopure N,N-acetal pyrimidinone (S)-1, a masked chiral derivative of β-alanine.
[Structure: see text] The enantioselectivehydrogenation of beta-phthalimide acrylates provides the corresponding chiral beta2-amino acids in excellent enantiomeric excess catalyzed by Rh-monophosphorus.
Amino acid synthesis via ring opening of N-sulphonyl aziridine-2-carboxylate esters with organometallic reagents.
作者:Jack E. Baldwin、Alan C. Spivey、Christopher J. Schofield、Joseph B. Sweeney
DOI:10.1016/s0040-4020(01)87968-0
日期:1993.7
Nucleophilic ringopening of optically active N-sulphonyl aziridine-2-carboxylateesters with organometallicreagents has been investigated as a method of preparation of optically active amino acids.