90656-90-9Relevant academic research and scientific papers
Asymmetric Aza-Diels-Alder Reactions of in Situ Generated β,β-Disubstituted α,β-Unsaturated N-H Ketimines Catalyzed by Chiral Phosphoric Acids
He, Shunlong,Gu, Huanchao,He, Yu-Peng,Yang, Xiaoyu
, p. 5633 - 5639 (2020/07/14)
A novel asymmetric synthesis of dihydropyridinones with vicinal quaternary stereocenters has been realized by asymmetric aza-Diels-Alder reactions of 3-amido allylic alcohols with oxazolones enabled by chiral phosphoric acid catalysis. A series of aryl/alkyl- and alkyl/alkyl-disubstituted 3-amido allylic tertiary alcohols and 4-substituted oxazolones could be well tolerated in these reactions, producing dihydropyridinones with excellent diastereoselectivities and high enantioselectivities. Mechanistic study and control experiments were performed to shed light on the reaction mechanism, in which a configurationally defined β,β-disubstituted α,β-unsaturated N-H ketimine was proposed as the key intermediate.
Group-Assisted Purification Chemistry for Asymmetric Mannich-type Reaction of Chiral N-Phosphonyl Imines with Azlactones Leading to Syntheses of α-Quaternary α,β-Diamino Acid Derivatives ?
Zhang, Haowei,Yang, Zhen,Zhao, Brian Nlong,Li, Guigen
, p. 644 - 655 (2018/01/27)
An asymmetric Mannich-type reaction between chiral N-phosphonyl imines and azlactones [oxazol-5(4H)-ones] has been established under convenient conditions at room temperature. The reaction was performed without using any bases, additives, or catalysts to achieve up to excellent chemical yields and diastereoselectivity for 32 examples. The α-quaternary syn-α,β-diamino acid products were purified simply by washing the crude mixtures with cosolvents, following the group-assisted purification chemistry/technology, without involving traditional chromatography or recrystallization methods. The auxiliary can be readily removed and recycled for reuse. The absolute configuration was unambiguously assigned by X-ray structural analysis.
Alkynyliodonium salt mediated alkynylation of azlactones: Fast access to Cα-tetrasubstituted α-amino acid derivatives
Finkbeiner, Peter,Weckenmann, Nicole M.,Nachtsheim, Boris J.
supporting information, p. 1326 - 1329 (2014/04/03)
An efficient electrophilic alkynylation of azlactones (oxazol-5(4H)-ones) is developed using alkynyl(phenyl)iodonium salts as the electrophilic alkyne source. After remarkably short reaction times, the desired alkyne functionalized azlactones are obtained in 60-97% yield and can be transformed easily into a variety of quaternary α-amino acid derivatives.
CYCLIC NATRIURETIC PEPTIDE CONSTRUCTS
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Page/Page column 66, (2008/06/13)
Cyclic constructs with an N-terminus and a C-terminus which bind to a natriuretic peptide receptor and include a plurality of amino acid residues, at least one amino acid surrogate of formula I: where R, R', Q, Y, W, Z, J, x and n are as defined in the specification, and optionally at least one prosthetic group, pharmaceutical compositions including such cyclic constructs, and methods of treating congestive heart failure or other conditions, syndromes or diseases for which induction of anti hypertensive, cardiovascular, renal or endocrine effects are desired.
HYDROXY SUBSTITUTED UREIDO AMINO AND IMINO ACIDS
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, (2008/06/13)
Compounds of the formula STR1 are disclosed. These compounds are useful as hypotensive agents due to their angiotensin converting enzyme inhibition activity and depending upon the definition of X may also be useful as analgesics due to their enkephalinase
