3304-59-4Relevant articles and documents
Transfer hydrogenation reactions catalyzed by chiral half-sandwich Ruthenium complexes derived from Proline
Pandia Kumar, Arun Kumar,Samuelson, Ashoka G
, p. 1405 - 1415 (2016/09/19)
Chiral ruthenium half-sandwich complexes were prepared using a chelating diamine made from proline with a phenyl, ethyl, or benzyl group, instead of hydrogen on one of the coordinating arms. Three of these complexes were obtained as single diastereoisomers and their configuration identified by X-ray crystallography. The complexes are recyclable catalysts for the reduction of ketones to chiral alcohols in water. A ruthenium hydride species is identified as the active species by NMR spectroscopy and isotopic labelling experiments. Maximum enantio-selectivity was attained when a phenyl group was directly attached to the primary amine on the diamine ligand derived from proline. [Figure not available: see fulltext.]
Microwave spectroscopy of the twist C(β)-exo/C(γ)-endo conformation of prolinamide
Kuhls, Kimberly A.,Centrone, Charla A.,Tubergen, Michael J.
, p. 10194 - 10198 (2007/10/03)
The rotational transitions of three isotopomers of prolinamide were measured with a Fourier-transform microwave spectrometer. A twist pyrrolidine ring conformation with C(β)-exo and C(γ)-endo reproduces the experimental moments of inertia. Stark-effect measurements of five [M] components were used to determine that the dipole moment of this conformation of prolinamide is 3.83(4) D. Kraitchman's method of isotopic substitution was used to determine an N-N distance of 2.684(2) A?.
A Simple and Mild Esterification Method for Carboxylic Acids Using Mixed Carboxylic-Carbonic Anhydrides
Kim, Sunggak,Lee, Jae In,Kim, Youn Chul
, p. 560 - 565 (2007/10/02)
A simple and mild esterification method using mixed carboxylic-carbonic anhydrides has been developed.Simple aliphatic carboxylic esters are prepared in high yields by the reaction of acids with equimolar amounts of chloroformates (2,2,2-trichloroethyl chloroformate is an exception) and triethylamine in the presence of a catalytic amount of 4-(dimethylamino)pyridine.Although aromatic acids give a mixture of the ester, the acid anhydride, and the carbonate under normal conditions utilized in this study, it is found that increasing the amount of 4-(dimethylamino)pyridine drastically decreases the formation of the acid anhydride and the carbonate, affording a satisfactory yield of the ester.This method reaches a limit with sterically hindered acids and the formation of the acid anhydride and the carbonate is favored.
