Modified Guanidines as Potential Chiral Superbases. 2. Preparation of 1,3-Unsubstituted and 1-Substituted 2-Iminoimidazolidine Derivatives and a Related Guanidine by the 2-Chloro-1,3-dimethylimidazolinium Chloride-Induced Cyclization of Thioureas
摘要:
Simple preparation methods for modified guanidines were explored for new chiral superbases, Thus, (4S,5S)-4,5-diphenyl- and diastereomeric cyclohexane-fused 2-iminoimidazolidines were prepared from (1S,2S)-1,2-diphenylethylenediamine and (1R,2R)- or (1S,2S)-1,2-diaminocyclohexanes through cyclization of protected thiourea intermediates with 2-chloro-1,3-dimethylimidazolinium chloride (DMC) as a key reaction. In the (4S,SS)-4,5-diphenyl series 1-methyl-2-iminoimidazolidines and 2-diethylaminoimidazoline were also prepared as related guanidines.
Modified Guanidines as Potential Chiral Superbases. 2. Preparation of 1,3-Unsubstituted and 1-Substituted 2-Iminoimidazolidine Derivatives and a Related Guanidine by the 2-Chloro-1,3-dimethylimidazolinium Chloride-Induced Cyclization of Thioureas
摘要:
Simple preparation methods for modified guanidines were explored for new chiral superbases, Thus, (4S,5S)-4,5-diphenyl- and diastereomeric cyclohexane-fused 2-iminoimidazolidines were prepared from (1S,2S)-1,2-diphenylethylenediamine and (1R,2R)- or (1S,2S)-1,2-diaminocyclohexanes through cyclization of protected thiourea intermediates with 2-chloro-1,3-dimethylimidazolinium chloride (DMC) as a key reaction. In the (4S,SS)-4,5-diphenyl series 1-methyl-2-iminoimidazolidines and 2-diethylaminoimidazoline were also prepared as related guanidines.
Chiral thiourea compounds and process for enantioselective reduction of ketones
申请人:Li Derun
公开号:US20090253919A1
公开(公告)日:2009-10-08
Chiral thioureas are effective catalysts for the borane reduction of prochiral ketones to optically active alcohols. A prochiral ketone may be reduced to an optically active alcohol in the presence of a substantially sub-stoichiometric amount of chiral thiourea. The asymmetric thiourea compound of the present invention may be produced according to a production method described herein.
A Simple Organocatalytic Enantioselective Synthesis of Pregabalin
作者:Oriol Bassas、Juhani Huuskonen、Kari Rissanen、Ari M. P. Koskinen
DOI:10.1002/ejoc.200801220
日期:2009.3
synthetic sequence is the Michaeladdition reaction of Meldrum's acid to a nitroalkene mediated by a quinidine derived thiourea. A variety of novel catalysts bearing different groups at the thiourea moiety were synthesized and tested. The most successful catalyst that incorporates a trityl substituent provided up to 75 % ee of (S)-4. The conjugate addition reaction was carried out on a multigram scale
(<i>R</i>)-[1-(1-Naphthyl)ethyl] Isothiocyanate and (<i>S</i>)-1-Phenylethyl Isothiocyanate. New Chirality Recognizing Reagents for the Determination of Enantiomeric Purity of Chiral Amines by NMR
作者:Dong Ju Jeon、Jung Soo Kim、Jung No Lee、Hyoung Rae Kim、Eung K. Ryu
DOI:10.1246/cl.2000.40
日期:2000.1
(S)-1-Phenylethyl isothiocyanate and (R)-[1-(1-naphthyl)ethyl] isothiocyanate which are easily formed and stable in aqueous conditions are utilized as new chirality recognizing reagents for the determination of enantiomeric purity of chiral amines by NMR.
Highly enantioselective addition of ketones to nitroolefins catalyzed by new thiourea–amine bifunctional organocatalysts
作者:Svetlana B. Tsogoeva、Shengwei Wei
DOI:10.1039/b517937h
日期:——
and effective organocatalytic system: primary amine derived chiral thiourea catalyst and AcOH-H2O additive, which converts different ketones to gamma-nitroketones in high yields (82-99%) and enantioselectivities (90-99%) has been described.
Crystallographic, 1H NMR and CD studies of sterically strained thiourea anion receptors possessing two stereogenic centres
作者:Haslin Dato Paduka Ali、Susan J. Quinn、Thomas McCabe、Paul E. Kruger、Thorfinnur Gunnlaugsson
DOI:10.1039/b819638a
日期:——
three chiral bis-naphthalene thiourea receptors (1–3) derived from (R)-(+)-1-(1-naphthyl)ethylamine and (S)-(−)-1-(1-naphthyl)ethylamine are reported along with spectroscopic studies to screen their potential as anion receptors/sensors. Their solid state structures were analysed by X-ray crystallography and their ability to bind anions such as acetate and phosphate in DMSO solution investigated by 1H
三种衍生自手性的双萘硫脲受体(1-3)的合成和结构表征(R)-(+)-1-(1-萘基)乙胺 和 (S)-(-)-1-(1-萘基)乙胺与光谱研究一起被报道以筛选其作为阴离子受体/传感器的潜力。通过X射线晶体学分析它们的固态结构,并通过1 H NMR,吸收,荧光和圆二色谱法研究它们在DMSO溶液中与阴离子如乙酸根和磷酸根结合的能力。