Atropisomerism in some N,N'-diaryl-2-iminothiazoline derivatives: chiral separation and configurational stability

Abstract

Semi-preparative resolution of the atropisomers by chiral liquid chromatography and determination of the barriers to rotation has allowed an unequivocal identification of the regioisomers produced by the reaction between N-(2-methoxyphenyl)-N'-(2-methylphenyl)thiourea and α-chloroacetone. Attention is drawn on the potential use of these optically pure atropisomers as new non-biaryl ligands for enantioselective metal catalysis.

Atropisomerism in the 2-Arylimino-N-(2-hydroxyphenyl)thiazoline Series: Influence of Hydrogen Bonding on the Racemization Process

“…Iminothiazolines 1a (Me, Me) and 1d (MeO, MeO) were issued from the respective symmetrical thioureas and were thus obtained as single compounds. Access to 1b (MeO, Me) and 1c (Me, MeO) required chromatographic separation since they were simultaneously obtained when dis-symmetrical N -(2-methoxyphenyl)- N ‘-(2-methylphenyl)thiourea was reacted with 1-chloropropan-2-one . Access to iminothiazolines 1e − i was designed through demethylation of the methoxy analogues.…”

“…Synthesis. N -[(2 Z )-4-Methyl-3-(2-methylphenyl)-1,3-thiazol-2(3 H )-ylidene]- N -(2-methylphenyl)amine ( 1a ) (Me, Me), N -[(2 Z )-3-(2-methoxyphenyl)-4-methyl-1,3-thiazol-2(3 H )-ylidene]- N -(2-methylphenyl)amine ( 1b ) (MeO, Me), N -(2-methoxyphenyl)- N -[(2 Z )-4-methyl-3-(2-methylphenyl)-1,3-thiazol-2(3 H )-ylidene]amine ( 1c ) (Me, MeO), N -(2-methoxyphenyl)- N -[(2 Z )-3-(2-methoxyphenyl)-4-methyl-1,3-thiazol-2(3 H )-ylidene]amine ( 1d ) (MeO, MeO), 3-(2-methoxyphenyl)-4-methyl-1,3-thiazol-2(3 H )-one ( 2a ), 3-(2-hydroxyphenyl)-4-methyl-1,3-thiazol-2(3 H )-one ( 2b ), and 3-(2-methoxyphenyl)-4-methyl-1,3-thiazole-2(3 H )-thione ( 3a ), 3-(2-hydroxyphenyl)-4-methyl-1,3-thiazole-2(3 H )-thione ( 3b ) have already been described. , They were available for the present study.…”

“…Very little is known about atropisomerism in 2-arylimino-3-arylthiazoline derivatives. Limited information came from our previous paper which described the synthesis, the resolution on chiral support, and the stereodynamics of 1a (X = Y = Me), 1b (MeO, Me), 1c (Me, MeO), and 1d (MeO, MeO) …”

Isothiocyanyl Alanine as a Synthetic Intermediate for the Synthesis of Thioureayl Alanines and Subsequent Aminotetrazolyl Alanines

“…After the successful synthesis of NCS Ala, we thought that it would be worthwhile to exploit the electrophilicity of the −NCS functionality first to achieve the synthesis of the hitherto unreported side-chain chiral thioureayl alanines ( TU Ala = Tua). Thioureas constitute an important class of compounds that possesses widespread applications in medicinal chemistry, as valuable building blocks for the synthesis of amides, guanidines, and a variety of heterocycles, for anion recognition/sensing and in organocatalysis . Thus, several methodologies have been reported for the synthesis of thioureas.…”

Synthesis and chiral separation of atropisomers of 4,5‐Di methyl ∆4 N‐phenyl N‐aryl imidazoline‐2‐thione derivatives

“…21 Recently, Roussel et al reported complete experimental and theoretical studies relating to the synthesis, evaluation of the barriers to rotation and resolution of atropisomeric enantiomers by chromatography on chiral supports of a series of original atropisomeric N-aryliminothiazolines. 22,23 More recently, Allouch et al developed an investigation focused on the atropisomerism separation of racemic of 2-aryl-imino-N-(2-aryl)-thiazoline by reversed-phase (RP)-HPLC using several types of cyclodextrins, in which HP-γ-CD is the only additive that showed a capacity to form the complex and to achieve the separation of 2-aryl-imino-N-(2-aryl)thiazoline. 24 Imidazole-2-thiones are an interesting class of heterocyclic compounds.…”