133445-98-4Relevant academic research and scientific papers
Enantioselective Synthesis of Pyroglutamic Acid Esters from Glycinate via Carbonyl Catalysis
Ma, Jiguo,Zhou, Qinghai,Song, Guanshui,Song, Yongchang,Zhao, Guoqing,Ding, Kuiling,Zhao, Baoguo
, p. 10588 - 10592 (2021)
Direct α-functionalization of NH2-free glycinates with relatively weak electrophiles such as α,β-unsaturated esters still remains a big challenge in organic synthesis. With chiral pyridoxal 5 d as a carbonyl catalyst, direct asymmetric conjugated addition at the α-C of glycinate 1 a with α,β-unsaturated esters 2 has been successfully realized, to produce various chiral pyroglutamic acid esters 4 in 14–96 % yields with 81–97 % ee's after in situ lactamization. The trans and cis diastereomers can be obtained at the same time by chromatography and both of them can be easily converted into chiral 4-substituted pyrrolidin-2-ones such as Alzheimer's drug Rolipram (11) with the same absolute configuration via tert-butyl group removal and subsequent Barton decarboxylation.
Multicomponent synthesis of pyroglutamic acid derivatives: Via Knoevenagel-Michael-hydrolysis-lactamization-decarboxylation (KMHL-D) sequence
Khopade, Tushar M.,Warghude, Prakash K.,Sonawane, Amol D.,Bhat, Ramakrishna G.
supporting information, p. 561 - 566 (2019/01/24)
A novel and practical method for the synthesis of 3-substituted pyroglutamic acid derivatives is described. One pot multicomponent reaction of Meldrum's acid, aldehyde and Schiff's base followed an unprecedented chemoselective Knoevenagel-Michael-hydrolysis-lactamization domino sequence to afford 4-carboxy 3-substituted pyroglutamic acid derivatives under mild conditions. A carboxy intermediate formed appears to accelerate its own formation. The generality of the synthesis is exemplified by the use of a wide variety of aldehydes including enolizable aliphatic aldehydes, while substrates are stable under reaction conditions.
Diastereoselective Synthesis of Substituted Glutamic Acid Derivatives via Michael Additions of N-glycinates under Solid-Liquid Phase Transfer Catalysis
Alvarez-Ibarra, Carlos,Csaky, Aurelio G.,Maroto, Mercedes,Quiroga, M. Luz
, p. 6700 - 6705 (2007/10/03)
Michael additions of the enolates of ethyl and tert-butyl N-glycinates with α,β-unsaturated esters and ketones under solid-liquid phase transfer catalysis allowed for the highly diastereoselective synthesis of substituted glutami
Highly Diasteroselective Michael-Addition of Lithiated Camphor Imines of Glycine Esters to α,β-Unsaturated Esters. Synthesis of Optically Pure 5-Oxo-2,4-pyrrolidinedicarboxylates of Unnatural Stereochemistry
Kanemasa, Shuji,Tatsukawa, Akira,Wada, Eiji
, p. 2875 - 2883 (2007/10/02)
The lithium enolates of camphor imines of glycine esters underwent highly diastereoselective Michael additions to the α,β-unsaturated esters.The tightly chelated structure of the Z,E enolates and the selective approach of the α,β-unsaturated esters to the
