3304-59-4Relevant academic research and scientific papers
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.]
Synthesis, characterisation and in vitro cytotoxicity studies of a series of chiral platinum(II) complexes based on the 2-aminomethylpyrrolidine ligand: X-ray crystal structure of [PtCl2(R-dimepyrr)] (R-dimepyrr = N-dimethyl-2(R)-aminomethylpyrrolidine)
Diakos, Connie I.,Zhang, Mei,Beale, Philip J.,Fenton, Ronald R.,Hambley, Trevor W.
experimental part, p. 2807 - 2814 (2009/10/10)
A series of platinum(II) complexes were synthesised based on the enantiomerically pure amino acid proline. Novel synthetic pathways were developed, adapted from standard peptide chemistry, to produce the 2-aminomethylpyrrolidine (pyrr) ligand and its derivatives with differing arrangements of methyl substituents at the exocyclic amine sites. The crystal structure of [PtCl2(R-dimepyrr)] (R-dimepyrr = N,N-dimethyl-2(R)-aminomethylpyrrolidine) is reported and the five-membered ligand ring has been shown to be in an envelope conformation. Cytotoxicity studies were carried out on the ovarian cancer A2780 tumour cell line and its cisplatin-resistant variant, A2780cisR. Remarkably good activity was seen for several of the drugs when compared to cisplatin despite the addition of substantial steric bulk to the amine groups, and there was a lack of cross-resistance with cisplatin seen for some compounds.
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?.
Thermodynamic and (1)H NMR Study of Proton Complex Formation of Histidine-containing Cyclodipeptides in Aqueous Solution
Arena, Giuseppe,Impellizzeri, Giuseppe,Maccarrone, Giuseppe,Pappalardo, Giuseppe,Sciotto, Domenico,Rizzarelli, Enrico
, p. 371 - 376 (2007/10/02)
A thermodynamic and (1)H NMR study of proton complex formation in aqueous solution of some L-histidine-containing cyclic L-dipeptides has been carried out.The enthalpic and entropic changes associated with protonation of the cyclodipeptides, obtained by potentiometric and calorimetric measurements, together with the (1)H NMR data and NOESY experiments, enable the role played by non-covalent interactions in proton complex formation to be assessed.In addition, a comparison with c(Gly-His) permits the influence of side-chain residues on the conformation of protonated species to be observed.
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.
ACTIVATION OF A CARBOXY GROUP BY DIALKYL PYROCARBONATES. SYNTHESIS OF SYMMETRICAL ANHYDRIDES AND ARYL ESTERS OF N-PROTECTED AMINO ACIDS USING DI-tert-BUTYL PYROCARBONATE AS CONDENSING REAGENT
Pozdnev, V. F.,Chernaya, M. Yu.
, p. 333 - 337 (2007/10/02)
It has been shown that di-tert-butyl pyrocarbonate can be used as a condensing reagent in the production of anhydrides and some aryl esters of carboxylic acids.The synthesis of anhydrides and of phenyl, p-nitrophenyl, β-naphtyl, and quinolin-8-yl esters of N-protected amino acids is described.
Dichlorotris(dimethylamino)phosphorane as Dehydration Reagent for the Preparation of Activated (-ONp, -OPcp, -NSu)Esters of N-Protected Multifunctional Amino Acids
Appel, Rolf,Glaesel, Ursula
, p. 3511 - 3516 (2007/10/02)
Dichlorotris(dimethylamino)phosphorane (5) is an excellent reagent for the preparation of the activated esters of N-protected amino acids 7-9.Besides 4-nitrophenyl-, pentachlorophenyl-, and N-hydroxysuccinimide esters of various N-protected amino acids, in the presence of HOBt benzyloxycarbonyl-threonine N-hydroxysuccinimide ester was obtained for the first time.
Novel esterifying agents, and their production and use
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, (2008/06/13)
A process for esterifying organic carboxylic acids which comprises reacting an organic carboxylic acid with a carbonic acid ester of the formula: EQU1 wherein R is an organic group and X and Y are each a negative group in the presence of a basic substance to make esterified the carboxyl group in the organic carboxylic acid. The process is advantageous in affording the objective carboxylic ester in a good yield within a short time by a simple operation under a mild reaction condition.
