scholarly journals One-pot synthesis of enantiomerically pure N-protected allylic amines from N-protected α-amino esters

2016 ◽  
Vol 12 ◽  
pp. 957-962 ◽  
Author(s):  
Gastón Silveira-Dorta ◽  
Sergio J Álvarez-Méndez ◽  
Víctor S Martín ◽  
José M Padrón

An improved protocol for the synthesis of enantiomerically pure allylic amines is reported. N-Protected α-amino esters derived from natural amino acids were submitted to a one-pot tandem reduction–olefination process. The sequential reduction with DIBAL-H at −78 °C and subsequent in situ addition of organophosphorus reagents yielded the corresponding allylic amines without the need to isolate the intermediate aldehyde. This circumvents the problem of instability of the aldehydes. The method tolerates well both Wittig and Horner–Wadsworth–Emmons organophosphorus reagents. A better Z-(dia)stereoselectivity was observed when compared to the previous one-pot method. The (dia)stereoselectivity of the process was affected neither by the reaction solvent nor by the amount of DIBAL-H employed. The method is compatible with the presence of free hydroxy groups as shown with serine and threonine derivatives.

ChemInform ◽  
2016 ◽  
Vol 47 (36) ◽  
Author(s):  
Gaston Silveira-Dorta ◽  
Sergio J Alvarez-Mendez ◽  
Victor S Martin ◽  
Jose M Padron

2020 ◽  
Vol 24 (8) ◽  
pp. 900-908
Author(s):  
Ram Naresh Yadav ◽  
Amrendra K Singh ◽  
Bimal Banik

Numerous O (oxa)- and S (thia)-glycosyl esters and their analogous glycosyl acids have been accomplished through stereoselective glycosylation of various peracetylated bromo sugar with benzyl glycolate using InBr3 as a glycosyl promotor followed by in situ hydrogenolysis of resulting glycosyl ester. A tandem glycosylating and hydrogenolytic activity of InBr3 has been successfully investigated in a one-pot procedure. The resulting synthetically valuable and virtually unexplored class of β-CMGL (glycosyl acids) could serve as an excellent potential chiral auxiliary in the asymmetric synthesis of a wide range of enantiomerically pure medicinally prevalent β-lactams and other bioactive molecules of diverse medicinal interest.


SynOpen ◽  
2018 ◽  
Vol 02 (02) ◽  
pp. 0161-0167
Author(s):  
Magdalini Matziari ◽  
Yixin Xie

A simple and efficient synthetic method towards α-substituted acrylic esters has been developed using the Horner–Wadsworth–Emmons (HWE) reaction with HCHO after alkylation of phosphonoacetates in a one-pot reaction. This method allows the smooth introduction of various side-chains, such as natural amino acids and other biologically relevant substituents. The use of mild conditions, inexpensive reagents, short reaction times and simple work-up and purification steps provides an effective and general alternative to cumbersome multistep and low-yielding procedures described to date.


2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Juan I. Sarmiento-Sánchez ◽  
Adrián Ochoa-Terán ◽  
Ignacio A. Rivero

The efforts for synthesis of enantiomerically pure bis-(1,2,3-triazolylmethyl)amino esters6are reported in good yields from anin situgeneratedα-azidomethyl ketone. Optimum experimental conditions were established for preparation ofα-halomethyl ketones10andα-N,N-dipropargylamino esters11, all derived fromα-amino acids. The starting materials reacted under conventional click chemistry conditions, revealing a specific reactivity of bromomethyl ketones over chloromethyl ketones. The antioxidant activity of compounds6was assayed by DPPH method. The compound6cwith an IC50of 75.57 ± 1.74 μg mL−1was the most active. Technically, this methodology allows the preparation of a combinatorial library of analogues with different structural characteristics depending on the nature of the modifiedα-amino acids employed in the synthesis.


2018 ◽  
Vol 42 (3) ◽  
pp. 1595-1599 ◽  
Author(s):  
Mouhamad Jida ◽  
Steven Ballet

A new pathway towards enantiomerically pure 3-substituted piperazines, bearing a benzyl protecting group, has been developed in good overall yields (83–92%), starting from commercially available N-protected amino acids.


Author(s):  
Romana Pajkert ◽  
Henryk Koroniak ◽  
Pawel Kafarski ◽  
Gerd Volker Roeschenthaler

A one-pot, regioselective 1,3-dipolar cycloaddition of in situ generated (diethoxyphosphoryl)difluoromethyl nitrile oxide toward selected alkenes and alkynes is reported. This protocol enables facile access to 3,5-disubstituted isoxazolines and isoxazoles bearing...


Molecules ◽  
2021 ◽  
Vol 26 (5) ◽  
pp. 1466
Author(s):  
Ye Eun Kim ◽  
Hyunsung Cho ◽  
Yoo Jin Lim ◽  
Chorong Kim ◽  
Sang Hyup Lee

Studies on a one-pot synthesis of novel multisubstituted 1-alkoxyindoles 1 and their mechanistic investigations are presented. The synthesis of 1 was successfully achieved through consecutive four step reactions from substrates 2. The substrates 2, prepared through a two-step synthetic sequence, underwent three consecutive reactions of nitro reduction, intramolecular condensation, and nucleophilic 1,5-addition to provide the intermediates, 1-hydroxyindoles 8, which then were alkylated in situ with alkyl halide to afford the novel target products 1. We optimized the reaction conditions for 1 focusing on the alkylation step, along with the consideration of formation of intermediates 8. The optimized condition was SnCl2·2H2O (3.3 eq) and alcohols (R1OH, 2.0 eq) for 1–2 h at 40 °C and then, base (10 eq) and alkyl halides (R2Y, 2.0 eq) for 1–4 h at 25–50 °C. Notably, all four step reactions were performed in one-pot to give 1 in good to modest yields. Furthermore, the mechanistic aspects were also discussed regarding the reaction pathways and the formation of side products. The significance lies in development of efficient one-pot reactions and in generation of new 1-alkoxyindoles.


2016 ◽  
Vol 14 (2) ◽  
pp. 556-563 ◽  
Author(s):  
Veladi Panduranga ◽  
Girish Prabhu ◽  
Roopesh Kumar ◽  
Basavaprabhu Basavaprabhu ◽  
Vommina V. Sureshbabu

A simple and efficient method for the synthesis of N,N’-orthogonally protected imide tethered peptidomimetics is presented. The imide peptidomimetics were synthesized by coupling the in situ generated selenocarboxylate of Nα-protected amino acids with Nα-protected amino acid azides in good yields.


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