60687-33-4Relevant articles and documents
Regiodivergent Enantioselective γ-Additions of Oxazolones to 2,3-Butadienoates Catalyzed by Phosphines: Synthesis of α,α-Disubstituted α-Amino Acids and N,O-Acetal Derivatives
Wang, Tianli,Yu, Zhaoyuan,Hoon, Ding Long,Phee, Claire Yan,Lan, Yu,Lu, Yixin
supporting information, p. 265 - 271 (2016/01/25)
Phosphine-catalyzed regiodivergent enantioselective C-2- and C-4-selective γ-additions of oxazolones to 2,3-butadienoates have been developed. The C-4-selective γ-addition of oxazolones occurred in a highly enantioselective manner when 2-aryl-4-alkyloxazol-5-(4H)-ones were employed as pronucleophiles. With the employment of 2-alkyl-4-aryloxazol-5-(4H)-ones as the donor, C-2-selective γ-addition of oxazolones took place in a highly enantioselective manner. The C-4-selective adducts provided rapid access to optically enriched α,α-disubstituted α-amino acid derivatives, and the C-2-selective products led to facile synthesis of chiral N,O-acetals and γ-lactols. Theoretical studies via DFT calculations suggested that the origin of the observed regioselectivity was due to the distortion energy that resulted from the interaction between the nucleophilic oxazolide and the electrophilic phosphonium intermediate.
Synthesis and bioactivity of novel 3-(1-hydroxyethylidene)-5-substituted- pyrrolidine-2,4-dione derivatives
Han, Bao Feng,Shi, Qing Ming,Wang, Xian Feng,Liu, Jian Bo,Qiang, Sheng,Yang, Chun Long
experimental part, p. 1023 - 1026 (2012/10/08)
Ten novel 5-substituted derivatives of 3-(1-hydroxyethylidene)pyrrolidine- 2,4-dione were synthesized. The compounds were confirmed by IR, 1H NMR, MS and elemental analysis. The bioassay indicated that these compounds showed noticeable herbicid
Tandem multi-step synthesis of C-carboxyazlactones promoted by N-heterocyclic carbenes
Campbell, Craig D.,Duguet, Nicolas,Gallagher, Katherine A.,Thomson, Jennifer E.,Lindsay, Anita G.,O'Donoghue, AnnMarie C.,Smith, Andrew D.
supporting information; body text, p. 3528 - 3530 (2009/02/05)
Cascade reaction sequences incorporating N-heterocyclic carbene-based organocatalysis have been developed that allow the direct preparation of a range of (±)-4-phenoxycarbonylazlactones in good isolated yields (66-84%) from the corresponding N-p-anisoyl amino acids. The Royal Society of Chemistry.
Resolution of non-protein amino acids via the microbial protease-catalyzed enantioselective hydrolysis of their N-unprotected esters
Miyazawa, Toshifumi,Imagawa, Kiwamu,Minowa, Hiroe,Miyamoto, Toyoko,Yamada, Takashi
, p. 10254 - 10261 (2007/10/03)
In the Aspergillus oryzae protease-catalyzed ester hydrolysis, substitution of N-unprotected amino acid esters for the corresponding N-protected amino acid esters resulted in a large enhancement of the hydrolysis rate, while the enantioselectivity was deteriorated strikingly when the substrates employed were the conventional methyl esters. This difficulty was overcome by employing esters bearing a longer alkyl chain such as the isobutyl ester. Utilizing this ester, amino acids carrying an aromatic side chain were resolved with excellent enantioselectivities (E=50 to >200). With amino acids bearing an aliphatic side chain also, good results in terms of the hydrolysis rate and enantioselectivity were obtained by employing such an ester as the isobutyl ester. Moreover, the enantioselectivity proved to be enhanced further by conducting the reaction at low temperature. This procedure was applicable to the case where the enantioselectivity was not high enough even by the use of the isobutyl ester.
New 2-(2'-phenyl-9'-benzyl-8'-azapurin-6'-ylamino)-carboxylic acid methylesters as ligands for A1 adenosine receptors.
Biagi,Giorgi,Pacchini,Livi,Scartoni
, p. 929 - 931 (2007/10/03)
Synthesis of a series of new 2-phenyl-9-benzyl-8-azaadenines bearing on N6 an alkyl or aralkyl chain having a carbonyloxymethyl group on the carbon bound to N6 were reported. The ester group could assure to the molecule a better water-solubility than the 8-azaadenines 2, 6 and 9 substituted with lipophilic groups synthesised in the past. Compounds synthesised demonstrated only little capability of binding A1 adenosine receptors.
Oxidative deprotection of diphenylmethylamines
Sampson, Peter B.,Honek, John F.
, p. 1395 - 1397 (2008/02/09)
(formula presented) The diphenylmethyl amino protecting group can be efficiently removed by initial oxidation of the amine to an imine by 2,3-dichloro-5,6-dicyanobenzoquinone. The resulting imine can then be easily hydrolyzed under mildly acidic conditions. This method is particularly well suited for the preparation of α-amino phosphinates and α-amino phosphonates.
Non-Proteinogenic Amino Acid Synthesis: Synthesis of β,γ-Unsaturated α-Amino Acids from Aspartic Acid
Baldwin, Jack E.,Moloney, Mark G.,North, Michael
, p. 6319 - 6330 (2007/10/02)
A general, stereospecific, synthesis of β,γ-unsaturated α-amino acids using the β-anion derived from aspartic acid is described.Keywords: aspartic acid; unsaturated acids
