Synthesis and enantioselective transport studies of optically active lipophilic proton-ionizable crown ethers containing a diarylphosphinic acid unit

Chiral Separation in Preparative Scale: A Brief Overview of Membranes as Tools for Enantiomeric Separation

“…Hollow fiber supported liquid membrane was applied for the enantioseparation of salbutamol and the ratio of chiral to achiral extractant was 1.0:0.6, the separation factor was up to 2.0 in the stripping phase [76]. In another study, protonated phenylethyl amine (3) and phenylglycinol (4) were enantioselective transported with four enantiopure lipophilic crown ethers containing a diarylphosphinic acid unit in an aqueous source phase/lipophilic organic bulk liquid membrane/aqueous receiving phase system controlled by the pH of the media [115]. In previous study, crown ethers also showed appreciable enantiomeric recognition [116].…”

Synthesis, experimental and theoretical studies on the factors influencing the pKa values of new crown ethers containing a diarylphosphinic acid unit

“…Crown ethers were synthesized by macrocyclization of the reported ethyl phosphinates 7 and 8 [5,7] and tetraethylene glycol ditosylate 9 in DMF using K2CO3 as a base (see Scheme 1). Synthesis of macrocycle 10 was reported earlier, but by increasing the temperature we achieved a better yield with shorter reaction time.…”

“…mp 107-111 °C (from methanol); Rf: 0.55 (silica gel TLC, methanol-CH2Cl2 1:5); IR (KBr) νmax 3424 (br), 1604,1590,1580,1510,1478,1441,1340,1276,1143,1096,1072,1034,972,893,756, 565 cm -1 ; 1 H-NMR (300 MHz, CD3OD, 25 °C): δ = 3.50-3.53 (m, 2H, OCH2), 3.65-3.73 (m, 12H, OCH2), 3.76 (s, 3H, complexed MeOH), 3.94-3.97 (m, 2H, OCH2), 6.88 (dd, J = 8.0 Hz, 5.7 Hz, 1H, ArH), 7.03 (dd, J = 9.0 Hz, 5.2 Hz, 2H, ArH), 7.35-7.40 (m, 1H, ArH), 7.93 (ddd, J = 13.5 Hz, 7.5 Hz, 1.5 Hz, 1H, ArH), 8.29 (dd, J = 9.1 Hz, 2.9 Hz, 1H, ArH), 8.88 (dd, J = 13.4 Hz, 2.9 Hz, 1H, ArH) ppm; 13 C-NMR (75 MHz, CD3OD, 25 °C): δ = 56. 5,61.7,68.0,70.6,70.6,70.9,71.2,73.4 (OCH2) 4. 7,9,10,12,13,15,4,7,10,13,16]pentaoxa-λ 5 -phosphacyclooctadecin-22-one (4) Macrocycle 13 (0.20 g, 0.38 mmol), dioxane (15 mL), aqueous HCl (15 mL).…”

Push or Pull for a Better Selectivity? A Study on the Electronic Effects of Substituents of the Pyridine Ring on the Enantiomeric Recognition of Chiral Pyridino-18-Crown-6 Ethers

“…As the industry is working harder to exclude any adverse effects from the other enantiomer of drug molecules [2,3], demand is increasing for devices capable of detecting enantiomers of chiral compounds [4][5][6] or separating them [7]. Chiral crown ethers have been utilized in many instances as sensor molecules [8][9][10][11][12] as well as selector molecules in chiral chromatography stationary phases [7,[13][14][15][16][17][18], or in transport applications [19][20][21].…”