Synthesis of optically active omeprazole by catalysis with vanadyl complexes with chiral Schiff bases

Abstract

A new method for the preparation of optically active omeprazole, consisting in asymmetric oxidation of the corresponding sulfide with the use of vanadyl complexes with chiral Schiff bases as the catalysts has been elaborated. The best results of the oxidation were achieved by the use of the combination VO(acac) 2 -2 [{(1S,2S,3R,5S) 3 hydroxymethyl 2,6,6 trimethyl bicyclo[3.1.1]hept 2 ylimino}methyl]phenol-N ethyl N,N diisopropylamine.

Chiral schiff bases synthesized from terpenes of pinane series in asymmetric metall complex oxidation of sulfides

“…One among the most effi cient and general synthetic procedures for the synthesis of optically active sulfoxides is the asymmetric metal complex oxidation of prochiral sulfi des. During recent years a constant attention was paid to the use as ligands in the asymmetric vanadium-catalyzed oxidation of sulfi des of compounds prepared from monoterpenoids [15][16][17][18][19][20][21][22] preferably with pinane skeleton [15][16][17][19][20][21].…”

“…One among the most effi cient and general synthetic procedures for the synthesis of optically active sulfoxides is the asymmetric metal complex oxidation of prochiral sulfi des. During recent years a constant attention was paid to the use as ligands in the asymmetric vanadium-catalyzed oxidation of sulfi des of compounds prepared from monoterpenoids [15][16][17][18][19][20][21][22] preferably with pinane skeleton [15][16][17][19][20][21].We showed recently [16] that the use of ligands Ia-Ic in the vanadium-catalyzed oxidation of methyl phenyl sulfi de (II) led to the formation of the corresponding sulfoxide III with the enantiomeric excess (ee) up to 32% (Scheme 1).The aim of this study was the synthesis of new ligands on the basis of the terpenoid of the pinane series, verbenol epoxide (V) and the investigation of the applicability of these ligands to the vanadium-catalyzed asymmetric Scheme 1.oxidation of several sulfi des as compared with the previously obtained ligands Ia-Ic.In the isomerization of verbenol epoxide (V) alongside diol VI and hydroxyketone VII α-hydroxyaldehyde VIII with a cyclopentane skeleton formed as a minor product [23-25] (Scheme 2). Although the confi guration at the atom C 6 was not established, it was shown [23] that the isomerization of epoxide V into compound VIII proceeded stereospecifi cally giving a single diastereomer.…”

Synthesis and Transformation of (-)-Isopulegol-Based Chiral β-Aminolactones and β-Aminoamides

“…Conjugate addition of nucleophiles to α -methylene- γ -lactones provides β -aminolactones, which increase the proportion of cells in the G2/M and S phase [ 3 ] and serve as water-soluble derivatives that might retain cytotoxicity through a prodrug mechanism [ 4 ]. Additionally, the transformation of β -aminolactones, formally β -amino esters, to their derivatives such as 1,3-aminalcohols, proved to use those chiral auxiliaries in the enantioselective synthesis of secondary alcohols or other pharmacons, e.g., esomeprazole [ 5 , 6 , 7 , 8 , 9 ]. Besides their value in enantioselective catalysis, 1,3-aminoalcohols are also excellent building blocks for the synthesis of various heterocyclic ring systems, such as 1,3-oxazines, 1,3-thiazines or 1,4-oxazepams [ 10 , 11 ].…”

Stereoselective Synthesis and Antiproliferative Activity of Monoterpene-Fused 2- Imino-1,3-oxazines

“…The transformation of enantiomerically purepinene to -amino acid derivatives such as 1,3-aminoalcohols was recently reported [3,10,15,16], and these synthons have proved to be useful chiral auxiliaries in the enantioselective synthesis of secondary alcohols or pharmacons, e.g. esomeprasol [17][18][19][20][21].…”