Synthesis of N-methyl-N-[(1S)-1-[(3R)-pyrrolidin-3-yl]ethyl]amine

N-Methyl-N-[(1S)-1-[(3R)-pyrrolidin-3-yl]ethyl]amine (1)(1) is a key intermediate in the preparation of premafloxacin (2), which was under development as an antibiotic for use against pathogens of veterinary importance. This paper describes the development of a practical, efficient, and stereoselective process for the preparation of 1 from isobutyl (3S)-3-[methyl[(1S)-1-phenylethyl]amino]butanoate (5c). The key steps in the synthetic sequence are an asymmetric Michael addition, which yields 5c, and a stereoselective alkylation, which yields (3S,4S)-3-allyl-1,4-dimethylazetidin-2-one (17).     

A practical and improved synthesis of (3S,5S)-3-[(tert-butyloxycarbonyl)methyl]- 5-[(methanesulfonyloxy)methyl]-2- pyrrolidinone

A practical and improved synthesis of (3S,5S)-3-[(tert-butyloxycarbonyl)methyl]-5-[(methanesulfonyloxy)methyl]-2-pyrrolidinone (1) is described. The key transformations involve a highly efficient reaction sequence consisting of ethoxycarbonylation, alkylation, hydrolysis, and decarboxylation to produce compound 10. The process described herein is practical, robust, and cost-effective, and it has been successfully implemented in a pilot plant to produce a multikilogram quantity of mesylate 1.     

RuCl_2[(S)-P-Phos]-[(S)-DAIPEN]催化芳香酮的不对称加氢反应

研究了钌-双膦-二胺配合物催化剂RuC1_2[(S)-P-Phos]-[(S)-DAIPEN][P-Phos:2,2',6,6'-四甲氧基-4,4'-双(二苯基膦基)-3,3'.二吡啶,DA肫N:1,1.二(4.甲氧苯基).2.异丙基.1,2.乙二胺]催化芳香酮不对称加氢反应的性能,考察了不同的碱、叔丁醇钾浓度、反应溶剂、底物/催化剂摩尔比等因素对反应活性和对映选择性的影响.在苯乙酮、叔丁醇钾、催化剂的摩尔比为1000:20:1,氢气压力为2 MPa,反应温度为30℃时,苯乙酮的转化率和α-苯乙醇的对映选择性(ee)分别达到了100%和88.5%,2'-溴苯乙醇的ee值町达97.1%.     

Conformational study of isotactic poly[(S)-5-methyl-1-heptene] and poly[(S)-2-methylbutyl vinyl ether] by IR spectroscopy

Infrared (IR) investigation of structurally analogous optically active polymers such as poly[(S)-5-methyl-1-heptene (1)] and poly[(S)-2-methylbutyl vinyl ether (2)] was carried out in the solid state, in the molten state, and in solution. Vibrational data are in accordance with the existence of helical conformations in solution and in the molten state for both polymers, confirming the previous suggestions based on optical rotation measurements. In particular, an accurate examination of the spectral region between 850 and 700 cm^?1, where characteristic absorptions of the sec-butyl group occur, enables us to assign the medium intensity band at 827 cm^?1 (present in both polymers in the solid state) to the GTTG^?T conformation of the side chains.     

Molecular and crystal structures of (6R, 7R, 14S)-6,14-etheno-7-[(1R)-1-hydroxyethyl]- and (6R, 7R, 14S)-6,14-etheno-7-[(1S)-1-hydroxyethyl]-6,7,8,14-tetrahydro-17-nor-17-phenylthebaine

The crystal structures and absolute configurations of (6R,7R,14S)-6,14-etheno-7-[(1R)-1-hydroxyethyl]-6,7,8,14-tetrahydro-17-nor-17-phenylthebaine and (6R,7R,14S)-6,14-etheno-7-[(1S)-1-hydroxyethyl]-6,7,8,14-tetrahydro-17-nor-17-phenylthebaine were established by X-ray diffraction analysis. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2245–2250, November, 1998.