scholarly journals Synthesis of -Hydroxy -Proline: Potential for Organocataly-sis Reactions

2019 ◽  
Vol 7 (4.14) ◽  
pp. 237
Author(s):  
M. T. Mohd Ali ◽  
. .
Keyword(s):  
Unnatural Amino Acids ◽  
Oxidation Reaction ◽  
Organic Molecule ◽  
Primary Alcohol ◽  
Enantioselective Synthesis ◽  
Synthetic Approach ◽  
Synthetic Strategy ◽  
Hydroxy Proline ◽  
Transformation Reaction ◽  
Hydrolysis Of

A chiral organic molecule, L-proline catalyzed an enantioselective transformation reaction has becoming interesting synthetic protocol especially in the area of organocatalysis. Herein, a synthetic approach towards -hydroxy--proline starting from bicyclic lactone lactam is hereby described. The syntheses utilized dicarboxylation reaction of bicyclic lacton lactam, followed by ether hydrolysis of the bicyclic ether and oxidation reaction of the primary alcohol. The synthetic strategy disclosed here allows further the enantioselective synthesis of a variety of unnatural amino acids based on -proline structure. 

Enantioselective Synthesis of the Sex Pheromone of Lichen Moth, Miltochrista calamine, and Its Diastereomer

Synlett ◽  
2021 ◽  
Author(s):  
Jiangchun Zhong ◽  
Gucheng Yuan ◽  
Jiawei Liu ◽  
Shihang Yu ◽  
Xueyang Wang ◽  
...  
Keyword(s):  
Sex Pheromone ◽  
Enantioselective Synthesis ◽  
Synthetic Approach ◽  
Chiral Auxiliaries ◽  
Synthetic Sex Pheromone ◽  
Key Steps

AbstractThe synthesis of a Miltochrista calamine sex pheromone and its diastereomer has been developed. The key steps of the synthetic approach involved Evans’ chiral auxiliaries and the addition of alkyne to aldehyde, which were firstly applied to prepare this sex pheromone and its diastereomer. The synthetic sex pheromone could be used to trap insects and study physiological and ecological questions of the lichen moth.

scholarly journals On Photocatalytic Activity of Systems of Titania/(Fe (II, III))-Type in Aqueous Suspensions

2018 ◽  
Vol 17 (6) ◽  
pp. 521-527
Author(s):  
V. A. Gorbunova ◽  
L. M. Sliapniova
Keyword(s):  
Photocatalytic Activity ◽  
Oxidation Reaction ◽  
High Photocatalytic Activity ◽  
Organic Dye ◽  
Iron Ions ◽  
Physico Chemical ◽  
Photocatalytic System ◽  
Initial Suspension ◽  
Hydrolysis Of ◽  
Chemical Water

. The photocatalytic activity of three systems, promising for chemical water purification technologies, was experimentally compared, based on a combination of titanium dioxide/(Fe(II, III)), applying to the model oxidation reaction of methylorange organic dye in an aqueous medium. Herewith the cases of photocatalytic systems were investigated, which are based on: a) titania hydrosol obtained by hydrolysis of titanium isobutylate; b) a similar hydrosol with addition of Fe(III) ions; c) suspension of ilmenite powder based on FeTiO3. As a result of the investigation, the increase of the rate of destruction of methylorange by more than two times was found in the system with the introduction of a small amount of iron ions into initial suspension of the TiO2 hydrosol (at the obtaining a medium with the Fe3+ concentration up to 3.7 × 10–5 M). In the photocatalytic system, based on the suspension of pretreated (with suphation and calcination) ilmenite powder, enough high photocatalytic activity (the degree of methylorange decomposition up to 77 %) was measured but at a higher exposure than for the case of systems based on the TiO2 hydrosol. For the photocatalytic systems of the type being investigated, a possible mechanism of increasing their oxidative activity was briefly considered, which requires an additional physico-chemical analysis.

scholarly journals One-pot synthesis of (R)-convolutamydine A involving in situ chiral organocatalyst formation

2015 ◽  
Vol 2 (1) ◽  
Author(s):  
Shengwei Wei ◽  
Bernhard Schmid ◽  
Fliur Z. Macaev ◽  
Serghei N. Curlat ◽  
Andrei V. Malkov ◽  
...  
Keyword(s):  
Enantioselective Synthesis ◽  
One Pot ◽  
One Pot Synthesis ◽  
Synthetic Strategy

Abstract The application of a convenient one-pot synthetic strategy, utilizing an in situ formed organocatalyst, to the enantioselective synthesis of anti-leukaemia agent (R)-convolutamydine A has been demonstrated.

scholarly journals 2,3-Diaminopropanols Obtained from d-Serine as Intermediates in the Synthesis of Protected 2,3-l-Diaminopropanoic Acid (l-Dap) Methyl Esters

Molecules ◽  
2020 ◽  
Vol 25 (6) ◽  
pp. 1313
Author(s):  
Andrea Temperini ◽  
Donatella Aiello ◽  
Fabio Mazzotti ◽  
Constantinos M. Athanassopoulos ◽  
Pierantonio De Luca ◽  
...  
Keyword(s):  
Amino Acid ◽  
Reductive Amination ◽  
Methyl Esters ◽  
Primary Amines ◽  
Synthetic Approach ◽  
Protecting Group ◽  
Synthetic Strategy ◽  
Crude Product ◽  
Diaminopropanoic Acid ◽  
Acid Labile

A synthetic strategy for the preparation of two orthogonally protected methyl esters of the non-proteinogenic amino acid 2,3-l-diaminopropanoic acid (l-Dap) was developed. In these structures, the base-labile protecting group 9-fluorenylmethyloxycarbonyl (Fmoc) was paired to the p-toluensulfonyl (tosyl, Ts) or acid-labile tert-butyloxycarbonyl (Boc) moieties. The synthetic approach to protected l-Dap methyl esters uses appropriately masked 2,3-diaminopropanols, which are obtained via reductive amination of an aldehyde prepared from the commercial amino acid Nα-Fmoc-O-tert-butyl-d-serine, used as the starting material. Reductive amination is carried out with primary amines and sulfonamides, and the process is assisted by the Lewis acid Ti(OiPr)4. The required carboxyl group is installed by oxidizing the alcoholic function of 2,3-diaminopropanols bearing the tosyl or benzyl protecting group on the 3-NH2 site. The procedure can easily be applied using the crude product obtained after each step, minimizing the need for chromatographic purifications. Chirality of the carbon atom of the starting d-serine template is preserved throughout all synthetic steps.

scholarly journals Synthesis of Substituted 1,3-Diesters of Glycerol Using Wittig Chemistry

2014 ◽  
Vol 9 (5) ◽  
pp. 1934578X1400900
Author(s):  
Henry IC Lowe ◽  
Ngeh J. Toyang ◽  
Charah T. Watson ◽  
Joseph Bryant
Keyword(s):  
Benzoic Acid ◽  
Natural Compound ◽  
Primary Alcohol ◽  
Synthetic Approach ◽  
Triphenyl Phosphine ◽  
Phosphonium Bromide ◽  
New Compounds ◽  
First Time ◽  
Wittig Reagent

1,3-di-O-Cinnamoyl-glycerol is a natural compound isolated from a Jamaican medicinal plant commonly referred to as Ball moss (Tillandsia recurvata). The synthesis of this compound was achieved via a Wittig chemistry process. The synthetic approach started with acylation of a di-protected glycerol with cinnamoyl chloride, deprotection of the glycerol moiety, reaction of the primary alcohol with bromo acetylbromide followed by treatment with triphenyl phosphine to give the corresponding phosphonium bromide. The phosphonium bromide was then converted in situ to the Wittig reagent which is the basis for a novel route to 1,3-di-O-cinnamoyl glycerol. Four analogs were also synthesized, three of which are new and are being reported in this article for the first time. The new compounds include 3-(3,4-diemthoxy-phenyl)-acrylic acid 2-hydroxy-3-(3-ptolyl-acryloyloxy)-propyl ester (3), 2-acetoxy-5-((E)-3-(3-((E’)-3-(3,4-dimethoxyphenyl)acryloyloxy)-2-hydropropoxy)-3-oxoprop-1-enyl)benzoic acid (4) and 4-((E)-3-(3-((E)-3-(3,4-dimethoxyphenyl)acryloyloxy)-2-hydropropoxy)-3-oxoprop-1-enyl)benzoic acid (5). The compounds showed no activity in our anticancer assay.

scholarly journals Development of a Divergent Route to Erythrina Alkaloids

Synlett ◽  
2020 ◽  
Vol 31 (04) ◽  
pp. 327-333 ◽  
Author(s):  
Jesper L. Kristensen ◽  
Sebastian Clementson ◽  
Mikkel Jessing ◽  
Paulo J. Vital
Keyword(s):  
Natural Products ◽  
Total Synthesis ◽  
19Th Century ◽  
First Generation ◽  
Second Generation ◽  
Enantioselective Synthesis ◽  
Third Generation ◽  
Synthetic Strategy ◽  
Erythrina Alkaloids ◽  
The 19Th Century

Erythrina alkaloids were identified at the end of the 19th century and today, more than 100 members of the erythrinane family have been isolated. They are characterized by a unique tetracyclic, α-tertiary spiroamine scaffold. Herein we detail our efforts towards the development of a divergent enantioselective synthesis of (+)-dihydro-β-erythroidine (DHβE) – one of the most prominent members of this intriguing family of natural products.1 Introduction2 Synthetic Strategy2.1 First Generation2.2 Second Generation2.3 Third Generation2.3.1 Radical Endgame2.3.2 Completion of the Total Synthesis3 Conclusion

Bimetallic Au–Pt Nanocomposites in the CO Oxidation Reaction: New Synthetic Approach and Evolution in the Course of Catalysis

2018 ◽  
Vol 483 (1) ◽  
pp. 251-255
Author(s):  
A. V. Budnikov ◽  
A. V. Naumkin ◽  
E. E. Said-Galiev ◽  
V. F. Tret’yakov ◽  
A. Yu. Vasil’kov
Keyword(s):  
Co Oxidation ◽  
Oxidation Reaction ◽  
Synthetic Approach ◽  
Co Oxidation Reaction

A Concise Enantioselective Synthesis of (S)-Preclamol via Asymmetric Catalytic Negishi Cross-Coupling Reaction

Synlett ◽  
2019 ◽  
Vol 30 (07) ◽  
pp. 860-862 ◽  
Author(s):  
Yun Zhou ◽  
Chunxiao Liu ◽  
Lifeng Wang ◽  
Leng Han ◽  
Shicong Hou ◽  
...  
Keyword(s):  
Total Yield ◽  
Coupling Reaction ◽  
Cross Coupling ◽  
Enantioselective Synthesis ◽  
Synthetic Approach ◽  
Chiral Drugs ◽  
Asymmetric Catalytic ◽  
Cross Coupling Reaction ◽  
Tertiary Carbon ◽  
Key Steps

A novel, concise, and efficient enantioselective synthesis of (S)-preclamol (87% ee, 51% total yield) has been developed. The key steps of this synthetic approach included cobalt-catalyzed asymmetric catalytic cross-coupling of α-bromo ester with arylzinc and the reduction of chiral ester to diol with a tertiary carbon atom. Moreover, it was demonstrated that our enantioselective Negishi cross-coupling was a powerful tool to construct stereogenic benzylmethyl center in chiral drugs on a gram scale.

scholarly journals Chemoenzymatic enantioselective synthesis of baclofen

1994 ◽  
Vol 72 (11) ◽  
pp. 2312-2317 ◽  
Author(s):  
Robert Chênevert ◽  
Michel Desjardins
Keyword(s):  
Enzymatic Hydrolysis ◽  
Acetic Anhydride ◽  
Aqueous Medium ◽  
Organic Medium ◽  
Enantioselective Synthesis ◽  
Enantioselective Syntheses ◽  
Hydrolysis Of

We report two different chemoenzymatic enantioselective syntheses of baclofen based on the distinction between enantiotopic ester groups in compounds bearing a prochiral centre. In the first approach, the key step is the highly stereoselective enzymatic hydrolysis of dimethyl 3-(4-chlorophenyl)glutarate by chymotrypsin in an aqueous medium. In the second approach, the key step is the enzyme-catalyzed esterification of 2-(4-chloropheny 1)-1,3-propanediol by acetic anhydride in the presence of a lipase in an organic medium.

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