A mild cyclodesulfurization of N-(2-hydroxyethyl)-N′-phenylthioureas to 2-phenylamino-2-oxazolines using TsCl/NaOH

Synthesis, crystal structure of some new 2‐(4‐methylbenzoylimino)‐3‐aryl‐4‐methyl‐1,3‐thiazolines

“…The optically pure atropisomers were obtained by resolution and their potential use as new non-biaryl ligands for enantioselective metal catalysis has been suggested [17]. The synthetic strategies for 2-iminothiazoles reported in the literature include the reaction of 1,2-diaza-1,3-butadienes with rhodanine affording 2-(mercaptoacetyl)iminothiazoline derivatives and by reaction of the same reagents with chiral 1,3-oxazolidine-2-thione derivatives [7,8], alkylation of 2-aminothiazoles obtained from condensation of -haloketones with thiourea [18], reaction of -bromoketimines with potassium thiocyanate [19], reaction of ketones with N-alkyl rhodanamines or bisbenzyl formamidine disulfide [20], reaction ofchloroketones with thiosemicarbazide in acidic medium [21] and the more recently reported synthesis of 2-imino-1,3-thiazolines from 1-arylmethyl-2-(bromomethyl) aziridines via ring transformation of 1-arylmethyl-2-(thiocyanomethyl)aziridines [22].…”

Diazaallyls of group 4 metals based on trans-1,2-diaminocyclohexane

“…Treatment of racemic trans-1,2-cyclohexylamine 1 with 1,1 0 -thiocarbonyldi-2(1H)-pyridone [16] gave the diisothiocyanate product 2 in 47% isolated yield after filtration through silica gel. Following the work of Kim et al on 2-phenylamino-2-oxazolines [17], the reaction of 2 with 2-amino-2-methyl-1-propanol was attempted. NMR analysis showed that addition of the amino alcohol to one isothiocyanate group was complete after stirring overnight at ambient temperature.…”

“…Although the model aminooxazoline 6 was synthesised readily by the route shown in Scheme 2, the attempted NaOH/TsCl mediated double ring-closure [17] of 3 (Scheme 1) to give the oxazoline analogue of H 2 L 2 proceeded only with one ring closure per molecule, despite the use of forcing condition, giving the product 7. This could be a result of steric crowding or a stabilising H-bonding effect in the latter.…”

A New Non‐Cross‐Linked Polystyrene Supported 2‐Phenylimino‐2‐oxazolidine Chiral Auxiliary: Synthesis and Application in Asymmetric Alkylation Reactions

“…Recently, a new class of chiral auxiliary, 2-phenylimino-2-oxazolidine, has been developed. [8] This improved auxiliary provides superior performance to many other chiral auxiliaries currently in common usage and has been proved to be particularly efficient in terms of stereoselectivity and yields in asymmetric alkylation reactions. [9,10] However, in most case, the expensive chiral auxiliaries could not be recovered after the reactions; to recycle these expensive materials, chiral auxiliaries have been supported onto polymers.…”