A comparative study on the acylative kinetic resolution of racemic fluorinated and non-fluorinated 2-methyl-1,2,3,4-tetrahydroquinolines and 3,4-dihydro-3-methyl-2H-[1,4]benzoxazines

Progress in the Chemistry of Tetrahydroquinolines

“…N -Acylation reactions have been used as the basis for kinetic resolution protocols of chiral 2-substituted tetrahydroquinolines 1506 and related heterocycles (Scheme ). These methods are based on the differential reactivity of both enantiomers toward chiral acyl chlorides such as compounds 1507 and 1510 …”

“…These methods are based on the differential reactivity of both enantiomers toward chiral acyl chlorides such as compounds 1507 627 and 1510. 628…”

Efficient Synthesis of β-Aryl-γ-lactams and Their Resolution with (S)-Naproxen: Preparation of (R)- and (S)-Baclofen

“…With the racemic β-aryl-γ-lactams ( 2a – f ) in hand, the next step was to explore the scope of ( S )-Naproxen as a resolution agent [26,27,28,29,30]. For this purpose, and after several attempts using Et 3 N/DMAP as base, we found that the reaction of the racemic β-phenyl-γ-lactam ( 2a ) with lithium diisopropylamide (LDA) in dry tetrahydrofuran at −78 °C, followed by the addition of ( S )-Naproxen acyl chloride 9 freshly prepared after reaction of ( S )-Naproxen with oxalyl chloride, produced the imides ( R , S )- 10a and ( S , S )- 10a as a diastereoisomeric mixture which, by careful separation by column chromatography, afforded the diastereoisomerically pure imides ( R , S )- 10a as minor polar and ( S , S )- 10a as more polar in 26% and 27% yield, respectively.…”

Enzymatic synthesis of novel purine nucleosides bearing a chiral benzoxazine fragment

“…Among them, compounds with high antimycobacterial were found (Krasnov et al., ). To obtain enantiomerically pure heterocyclic amines (the precursors of bases 1 and 2 ), the method of kinetic resolution of racemates was used (Gruzdev, Vakarov, Levit, & Krasnov, ; Gruzdev et al., ; Krasnov et al., ). Four bases of the series (conjugates of 2‐aminopurine with the enantiomers of 7,8‐difluoro‐3,4‐dihydro‐3‐methyl‐2 H ‐[1,4]benzoxazine [( R )‐ 1, 2 and ( S )‐ 1 , 2 ], (Figure ) were used in the enzymatic synthesis of β‐ D ‐arabinosides (Eletskaya et al., ).…”

“…Among them, compounds with high antimycobacterial were found (Krasnov et al, 2016). To obtain enantiomerically pure heterocyclic amines (the precursors of bases 1 and 2), the method of kinetic resolution of racemates was used (Gruzdev, Vakarov, Levit, & Krasnov, 2014;Gruzdev et al, 2013;Krasnov et al, 2003). (Eletskaya et al, 2016).…”