118916-60-2Relevant articles and documents
The first enantioselective approach to 13a-methyl-14- hydroxyphenanthroindolizidine alkaloids - Synthetic studies towards hypoestestatin 2
Su, Bo,Deng, Meng,Wang, Qingmin
, p. 1979 - 1985 (2013)
The first enantioselective approach to 13a-methyl-14- hydroxyphenanthroindolizidine alkaloids was achieved in six linear steps from phenanthryl alcohol and features a highly substrate-dependent Parham cycloacylation and Seebach's enantioselective alkylation as the key steps. The route is concise, protecting-group free, provides access to all stereoisomers, and works on a gram scale. In addition to the putative structure of hypoestestatin 2, the other three stereoisomers and two structurally related analogues were synthesized, none of which shows identical NMR spectra to those reported for natural hypoestestatin 2, which indicates that further structure revision is required. By using Seebach's stereoselective alkylation and Parham cyclization as key steps, the first strategy for the synthesis of 14-hydroxy-13a-methylphenanthroindolizidine alkaloids was developed. The route is practical (six steps in 30 % overall yield) and adaptable for all stereoisomers. In addition, we demonstrate for the first time that the structure of hypoestestatin 2 was misassigned.
4-Alkyl-2-trichloromethyloxazolidin-5-ones: Valuable precursors to enantiomerically pure C- and N-protected α-alkyl prolines
Wang, Harry,Germanas, Juris P.
, p. 33 - 36 (1999)
An efficient, economical and enantioselective method for preparation of various mono-and diprotected α-substituted proline derivatives is described. The lithium enolate of known 2-trichloromethyloxazolidin-5-one 3b reacted with electrophiles to furnish th
Design and stereoselective synthesis of ProM-2: A spirocyclic diproline mimetic with polyproline type II (PPII) helix conformation
Reuter, Cédric,Opitz, Robert,Soicke, Arne,Dohmen, Stephan,Barone, Matthias,Chiha, Slim,Klein, Marco Tobias,Neud?rfl, J?rg-Martin,Kühne, Ronald,Schmalz, Hans-Günther
, p. 8464 - 8470 (2015)
With the aim of developing polyproline type II helix (PPII) secondary-structure mimetics for the modulation of prolin-rich-mediated protein-protein interactions, the novel diproline mimetic ProM-2 was designed by bridging the two pyrrolidine rings of a diproline (Pro-Pro) unit through a Z-vinylidene moiety. This scaffold, which closely resembles a section of a PPII helix, was then stereoselectively synthesized by exploiting a ruthenium-catalyzed ring-closing metathesis (RCM) as a late key step. The required vinylproline building blocks, that is, (R)-N-Boc-2-vinylproline (Boc=tert-butyloxycarbonyl) and (S,S)-5-vinylproline-tert-butyl ester, were prepared on a gram scale as pure stereoisomers. The difficult peptide coupling of the sterically demanding building blocks was achieved in good yield and without epimerization by using 2-(1H-7-azabenzotriazol-1-yl)-1,1,3,3-tetramethyluronium hexafluorophosphate (HATU)/N,N-diisopropylethylamine (DIPEA). The RCM proceeded smoothly in the presence of the Grubbs II catalyst. Stereostructural assignments for several intermediates were secured by X-ray crystallography. As a proof of concept, it was shown that certain peptides containing ProM-2 exhibited improved (canonical) binding towards the Ena/VASP homology 1 (EVH1) domain as a relevant protein interaction target.
Synthesis and crystal structure of 6-Trichloromethyl-9-oxa-5-azatricyclo[6. 2.1.01,5]undecan-10-one
Yang, Hua,Sun, Mo Ran,Zhu, Ming
, p. 167 - 168 (2011)
6-Trichloromethyl-9-oxa-5-azatricyclo[6.2.1.01,5]undecan-10-one was prepared and its structure clearly established from spectroscopic data and X-ray crystallography. The crystal structure belongs to the orthorhombic system, space group P212121 with a = 8.4494(17), b = 9.3505(19), c = 15.315(3) A , α = β = γ = 90 °, V = 01210.0(4) A 3, Z = 4, Flack = 0.00(10). The absolute configuration of the title compound was determined as (1R,6R).
A Designed Approach to Enantiodivergent Enamine Catalysis
Macharia, Juliet,Wambua, Victor,Hong, Yun,Harris, Lawrence,Hirschi, Jennifer S.,Evans, Gary B.,Vetticatt, Mathew J.
, p. 8756 - 8760 (2017)
The rational design and implementation of enantiodivergent enamine catalysis is reported. A simple secondary amine catalyst, 2-methyl-l-proline, and its tetrabutylammonium salt function as an enantiodivergent catalyst pair delivering the enantiomers of α-functionalized aldehyde products in excellent enantioselectivities. This novel concept of designed enantiodivergence is applied to the enantioselective α-amination, aldol, and α-aminoxylation/α-hydroxyamination reactions of aldehydes.
Rational molecular design and EPC synthesis of a type VI β-turn inducing peptide mimetic
Hoffmann, Tobias,Lanig, Harald,Waibel, Reiner,Gmeiner, Peter
, p. 3361 - 3364 (2001)
A fruitful combination of molecular dynamics based design and modern synthetic reactions led to a conformatively rigidized cis-peptidyl proline surrogate (see picture). NMR spectroscopic experiments clearly show the existance of type VIa β-turn properties
Enantioselective approach to 13a-methylphenanthroindolizidine alkaloids
Su, Bo,Cai, Chunlong,Wang, Qingmin
, p. 7981 - 7987 (2012)
The first enantioselective approach to 13a-methylphenanthroindolizidine alkaloids is reported, featuring an efficient stereoselective Seebach's alkylation and Pictet-Spengler cyclization. The proposed and other three most probable structures were ruled out, indicating hypoestestatin 1 needs further assignment.
Preparation method of N-phenylacetyl-2-hydroxymethylpyrrolidine-2-formamide and medicinal application of N-phenylacetyl-2-hydroxymethylpyrrolidine-2-formamide
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Paragraph 0020; 0032; 0033, (2021/01/12)
The invention discloses N-phenylacetyl-2-hydroxymethylpyrrolidine-2-formamide as shown in a general formula (I), a preparation method of the compound, a new application of the compound and a pharmaceutical composition containing the compound in the aspect of inhibiting neuroglial cell inflammation. Wherein R1/R2 is equal to H, F, CF3 or OCF3.
Preparation method of (R)-1-alkanoyl-2-substituted pyrrolidine-2-formamide and medicinal application of (R)-1-alkanoyl-2-substituted pyrrolidine-2-formamide
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Paragraph 0019; 0031-0032, (2021/01/12)
The invention discloses (R)-1-alkanoyl-2-substituted pyrrolidine-2-formamide as shown in a general formula (I), a preparation method of a compound, a new application of the compound and a pharmaceutical composition containing the compound in the aspect of inhibiting neuroglial cell inflammation.
METHOD FOR PREPARATION OF ALPHA-METHYL-L-PROLINE
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Page/Page column 9-11, (2019/01/17)
The invention discloses a method for preparation of alpha-methyl-L-proline starting from proline and comprising three steps, first a conversion with chloral, then a conversion with methyl bromide and then a conversion with aqueous HCl.