Total Synthesis of Woodrosin I. Part 1. Preparation of the Building Blocks and Evaluation of the Glycosylation Strategy.

ChemInform ◽  
2003 ◽  
Vol 34 (18) ◽  
Author(s):  
Alois Fuerstner ◽  
Fabien Jeanjean ◽  
Patrick Razon ◽  
Conny Wirtz ◽  
Richard Mynott
Keyword(s):  
Total Synthesis ◽  
Building Blocks

scholarly journals Non-Enzymatic Desymmetrization Reactions in Aqueous Media

Symmetry ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 720
Author(s):  
Satomi Niwayama
Keyword(s):  
Natural Products ◽  
Total Synthesis ◽  
Functional Groups ◽  
Organic Compounds ◽  
Recent Progress ◽  
Aqueous Media ◽  
Building Blocks ◽  
Organic Reactions ◽  
Environmentally Benign ◽  
Enzymatic Desymmetrization

Symmetric organic compounds are generally obtained inexpensively, and therefore they can be attractive building blocks for the total synthesis of various pharmaceuticals and natural products. The drawback is that discriminating the identical functional groups in the symmetric compounds is difficult. Water is the most environmentally benign and inexpensive solvent. However, successful organic reactions in water are rather limited due to the hydrophobicity of organic compounds in general. Therefore, desymmetrization reactions in aqueous media are expected to offer versatile strategies for the synthesis of a variety of significant organic compounds. This review focuses on the recent progress of desymmetrization reactions of symmetric organic compounds in aqueous media without utilizing enzymes.

Stereocontrolled construction of key building blocks for the total synthesis of amphoteronolide B and amphotericin B

1987 ◽  
Vol 109 (7) ◽  
pp. 2205-2208 ◽  
Author(s):  
Kyriacos C. Nicolaou ◽  
R. A. Daines ◽  
J. Uenishi ◽  
W. S. Li ◽  
D. P. Papahatjis ◽  
...  
Keyword(s):  
Total Synthesis ◽  
Amphotericin B ◽  
Building Blocks

ChemInform Abstract: Stereocontrolled Construction of Key Building Blocks for the Total Synthesis of Amphoteronolide B and Amphotericin B.

ChemInform ◽  
1987 ◽  
Vol 18 (33) ◽  
Author(s):  
K. C. NICOLAOU ◽  
R. A. DAINES ◽  
J. UENISHI ◽  
W. S. LI ◽  
D. P. PAPAHATJIS ◽  
...  
Keyword(s):  
Total Synthesis ◽  
Amphotericin B ◽  
Building Blocks

Zur Totalsynthese des Human-Big-Gastrins I und seines 32-Leucin-Analogons (Vorläufige Mitteilung) / Total Synthesis of Human Big Gastrin I and the 32-Leucine Analogue (Preliminary Communication)

1977 ◽  
Vol 32 (7-8) ◽  
pp. 495-506 ◽  
Author(s):  
E. Wünsch ◽  
G. Wendlberger ◽  
A. Hallett ◽  
E. Jaeger ◽  
S. Knof ◽  
...  
Keyword(s):  
Total Synthesis ◽  
Building Blocks ◽  
Ion Exchange Chromatography ◽  
Exchange Chromatography ◽  
Protecting Groups ◽  
Side Chain ◽  
Tertiary Alcohols ◽  
Synthetic Product ◽  
Preliminary Communication ◽  
Final Purification

A new total synthesis of the tetratriacontapeptide amide corresponding to the proposed primary structure of human big gastrin I is described. The synthetic route was based on the preparation of six suitably protected fragments, related to sequence 28 - 34, 23 - 27, 21 - 22, 15-20, 9 - 14, and 1 - 8, to be used as building blocks for the total synthesis. The protecting groups were selected according to the Schwyzer-Wünsch strategy of maximum side chain protection based on tertiary alcohols, also for the imidazol function of histidine. Subsequent assembly of the six fragments by three different pathways using the highly efficient Wünsch-Weygand condensation procedure to ensure minimum racemization, followed by deprotection of the synthetic products via exposure to trifluoroacetic acid and final purification by ion-exchange chromatography on DEAE-Sephadex A-25 and partition chromatography on Sephadex G-25, led to human big gastrin I, homogeneous within the limits of the analytical methods used. The biological activity of the synthetic product proved to be 50 percent higher than that of human little gastrin I. The 32-leucine analogue of human big gastrin I was prepared in the same way.

scholarly journals Total synthesis of aStreptococcus pneumoniaeserotype 12F CPS repeating unit hexasaccharide

2017 ◽  
Vol 13 ◽  
pp. 164-173 ◽  
Author(s):  
Peter H Seeberger ◽  
Claney L Pereira ◽  
Subramanian Govindan
Keyword(s):  
Total Synthesis ◽  
Capsular Polysaccharide ◽  
Severe Disease ◽  
Building Blocks ◽  
Positive Bacterium ◽  
Linear Approach ◽  
Starting Point ◽  
Branching Points ◽  
Glycoconjugate Vaccines ◽  
Sequential Assembly

The Gram-positive bacteriumStreptococcus pneumoniaecauses severe disease globally. Vaccines that preventS. pneumoniaeinfections induce antibodies against epitopes within the bacterial capsular polysaccharide (CPS). A better immunological understanding of the epitopes that protect from bacterial infection requires defined oligosaccharides obtained by total synthesis. The key to the synthesis of theS. pneumoniaeserotype 12F CPS hexasaccharide repeating unit that is not contained in currently used glycoconjugate vaccines is the assembly of the trisaccharide β-D-GalpNAc-(1→4)-[α-D-Glcp-(1→3)]-β-D-ManpNAcA, in which the branching points are equipped with orthogonal protecting groups. A linear approach relying on the sequential assembly of monosaccharide building blocks proved superior to a convergent [3 + 3] strategy that was not successful due to steric constraints. The synthetic hexasaccharide is the starting point for further immunological investigations.

scholarly journals Total synthesis of TMG-chitotriomycin based on an automated electrochemical assembly of a disaccharide building block

2017 ◽  
Vol 13 ◽  
pp. 919-924 ◽  
Author(s):  
Yuta Isoda ◽  
Norihiko Sasaki ◽  
Kei Kitamura ◽  
Shuji Takahashi ◽  
Sujit Manmode ◽  
...  
Keyword(s):  
Total Synthesis ◽  
Building Block ◽  
Building Blocks ◽  
Solution Phase ◽  
Protecting Groups ◽  
Phase Synthesis ◽  
Solution Phase Synthesis

The total synthesis of TMG-chitotriomycin using an automated electrochemical synthesizer for the assembly of carbohydrate building blocks is demonstrated. We have successfully prepared a precursor of TMG-chitotriomycin, which is a structurally-pure tetrasaccharide with typical protecting groups, through the methodology of automated electrochemical solution-phase synthesis developed by us. The synthesis of structurally well-defined TMG-chitotriomycin has been accomplished in 10-steps from a disaccharide building block.

Synthesis of Optically Active 15-epi-9,14-Methylene Lipoxin A4

Synthesis ◽  
2018 ◽  
Vol 50 (06) ◽  
pp. 1246-1258
Author(s):  
Udo Nubbemeyer ◽  
Adile Duymaz ◽  
Jochen Körber ◽  
Carolin Hofmann ◽  
Dorothea Gerlach
Keyword(s):  
Total Synthesis ◽  
Building Block ◽  
Building Blocks ◽  
Optically Active ◽  
Protecting Groups ◽  
Lipoxin A4 ◽  
Methylene Bridge ◽  
Type Coupling ◽  
Important Field ◽  
Gain Access

The synthesis of lipoxin A4 and B4 analogues (LXA4, LXB4) to gain access to stabilized inflammation resolving compounds is an important field of research. Starting from known structural requirements of the natural compounds displaying biological activity and a broad investigation of their rapid metabolism, various LXA4 derivatives have been developed and tested. Focusing on variation and stabilization of the conjugated E,E,Z,E C7–C14 tetraene moiety of natural LXA4, a methylene bridge introduced between C9 and C14 might suppress any Z/E isomerization of the C11–C12 olefin. Intending to enable at least known structure variations in connection with the C1–C7 and the C15–C20 fragments, a convergent total synthesis starting from a known cycloheptatriene is developed. The C1–C8 building blocks are generated via six-step ex-chiral pool sequences starting from 2-deoxy-d-ribose delivering two 5,6-dihydroxy carboxylic acid derivatives with C7 aldehyde functions. The synthesis of the C8–C21 building block starts from a known cycloheptatriene 1-carbonester (C8–C14, C21) and hexanoyl chloride (C15–C20). After Friedel–Crafts-type coupling, the defined configuration of the C15 OH group is introduced via enantioselective reduction of the ketone precursor. Following an additional four steps, an aryl sulfone C9–C21 building block is completed ready for a key Julia–Kocienski olefination with the C1–C7 compounds. Finally, removal of the protecting groups completes the synthesis of the target optically active 9,14-methylene LXA4 methyl ester.

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