scholarly journals Total Synthesis of Caprazamycin A: Practical and Scalable Synthesis of syn-β-Hydroxyamino Acids and Introduction of a Fatty Acid Side Chain to 1,4-Diazepanone

2019 ◽  
Vol 141 (21) ◽  
pp. 8527-8540 ◽  
Author(s):  
Hugh Nakamura ◽  
Chihiro Tsukano ◽  
Takuma Yoshida ◽  
Motohiro Yasui ◽  
Shinsuke Yokouchi ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Total Synthesis ◽  
Side Chain ◽  
Hydroxyamino Acids ◽  
Scalable Synthesis

scholarly journals First total synthesis of the (±)-2-methoxy-6-heptadecynoic acid and related 2-methoxylated analogs as effective inhibitors of the Leishmania topoisomerase IB enzyme

2012 ◽  
Vol 84 (9) ◽  
pp. 1867-1875 ◽  
Author(s):  
Néstor M. Carballeira ◽  
Michelle Cartagena ◽  
Fengyu Li ◽  
Zhongfang Chen ◽  
Christopher F. Prada ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Total Synthesis ◽  
Leishmania Donovani ◽  
Dna Topoisomerase ◽  
Triple Bonds ◽  
Weak Intermolecular Interactions ◽  
Topoisomerase Ib ◽  
Effective Inhibition ◽  
Acetylenic Fatty Acid

The fatty acids (±)-2-methoxy-6Z-heptadecenoic acid, (±)-2-methoxy-6-hepta-decynoic acid, and (±)-2-methoxyheptadecanoic acid were synthesized and their inhibitory activity against the Leishmania DNA topoisomerase IB enzyme (LdTopIB) determined. Both 2-OMe-17:1 fatty acids were synthesized from 4-bromo-1-pentanol, the olefinic fatty acid in 10 steps and in 7 % overall yield, while the acetylenic fatty acid in 7 steps and in 14 % overall yield. The 2-OMe-17:0 acid was prepared in 6 steps and in 42 % yield from 1-hexa-decanol. The 2-OMe-17:1 acids inhibited LdTopIB, with the acetylenic acid displaying an EC50 = 16.6 ± 1.1 μM, but the 2-OMe-17:0 acid did not inhibit LdTopIB. The (±)-2-methoxy-6Z-heptadecenoic acid preferentially inhibited LdTopIB over the human TopIB enzyme. Unsaturation seems to be a prerequisite for effective inhibition, rationalized in terms of weak intermolecular interactions between the active site of LdTopIB and either the double or triple bonds of the fatty acids. Toxicity toward Leishmania donovani promastigotes was also investigated, resulting in the order acetylenic > olefinic > saturated with the (±)-2-methoxy-6-heptadecynoic acid displaying an EC50 = 74.0 ± 17.1 μM. Our results indicate that α-methoxylation decreases the toxicity of C17:1 fatty acids toward L. donovani promastigotes, but improves their selectivity index.

ChemInform Abstract: Total Synthesis of a New 7-Deoxyidarubicinone Derivative Through the Functionalization of an A-Ring Side Chain.

ChemInform ◽  
2000 ◽  
Vol 31 (49) ◽  
pp. no-no
Author(s):  
Young S. Rho ◽  
Hyun Kyoung Ko ◽  
Wan-Joong Kim ◽  
Dong Jin Yoo ◽  
Heun Soo Kang
Keyword(s):  
Total Synthesis ◽  
Side Chain

scholarly journals Asymmetric and Regiospecific Synthesis of Isotopically Labelled Cyclopropane Fatty Acid (9R,10S)-Dihydrosterculic Acid: Overcoming Spontaneous Protonation During Lithium-Sulfoxide Exchange­

SynOpen ◽  
2018 ◽  
Vol 02 (02) ◽  
pp. 0168-0175
Author(s):  
Samuel Shields ◽  
Peter Buist ◽  
Jeffrey Manthorpe
Keyword(s):  
Fatty Acid ◽  
Total Synthesis ◽  
Cyclopropane Ring ◽  
Rapid Quenching ◽  
Cyclopropane Fatty Acid ◽  
Deuterium Incorporation ◽  
Biologically Relevant ◽  
Dihydrosterculic Acid

The total synthesis of isotopically labelled (9R,10S)-dihydro­sterculic acid, a usual cyclopropane fatty acid with biologically relevant toxicity upon desaturation in vivo, is reported. A diastereoselective Corey­–Chaykovsky reaction was employed to form the cyclopropane ring. Rapid quenching of a lithium-sulfoxide exchange was required to achieve the requisite high levels of deuterium incorporation.

scholarly journals Enzymatic β-Oxidation of the Cholesterol Side Chain in Mycobacterium Tuberculosis Bifurcates Stereospecifically at Hydration of 3-Oxo-Cholest-4,22- Dien-24-Oyl-CoA

2021 ◽  
Author(s):  
Tianao Yuan ◽  
Joshua Werman ◽  
Xingyu Yin ◽  
Meng Yang ◽  
Miguel Garcia-Diaz ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Fatty Acid ◽  
Alcohol Dehydrogenase ◽  
Side Chain ◽  
Crystallographic Structure ◽  
X Ray ◽  
Steroid Substrate ◽  
Unique Ability ◽  
Therapeutics Development ◽  
Chain Type

<p>The unique ability of <i>Mycobacterium tuberculosis </i>(Mtb) to utilize host lipids such as cholesterol for survival, persistence, and virulence has made the metabolic pathway of cholesterol an area of great interest for therapeutics development, and bioproduction of valuable sterol intermediates. Herein, we identify and characterize two genes from the <a></a><a>Cho-region of the Mtb genome</a>, <i>chsH3 </i>(Rv3538) and <i>chsB1</i> (Rv3502c). Their protein products catalyze <a></a><a>two sequential stereospecific</a>hydration and dehydrogenation steps in the b-oxidation of the cholesterol side chain. ChsH3 favors the <i>22S</i> hydration of 3-oxo-cholest-4,22-dien-24-oyl-CoA in contrast to the previously reported EchA19 (Rv3516) which catalyzes formation of the (<i>22R</i>)-hydroxy-3-oxo-cholest-4-en-24-oyl-CoA from the same enoyl-CoA substrate. ChsB1 is stereospecific and catalyzes dehydrogenation of the ChsH3 product, but not the EchA19 product. The X-ray crystallographic structure of the ChsB1 apo-protein was determined at a resolution of 2.03 Å and the holo-enzyme with bound NAD<sup>+</sup> cofactor at 2.21 Å.The homodimeric structure is representative of a classical NAD<sup>+</sup> utilizing short-chain type alcohol dehydrogenase/reductase, including a Rossmann-fold motif, but exhibits a unique substrate binding site architecture that is of greater length and width than its homologous counterparts, likely to accommodate the bulky steroid substrate. Intriguingly, Mtb utilizes MaoC-like hydratases in sterol side-chain catabolism in contrast to fatty acid b-oxidation in other species that utilize the evolutionarily distinct crotonase family of hydratases. </p>

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.

Synthesis of Dichotomin A: Use of a Penicillamine-Derived Pseudoproline to Furnish Native Valine Residues

2015 ◽  
Vol 68 (4) ◽  
pp. 627 ◽  
Author(s):  
Michelle S. Y. Wong ◽  
Deni Taleski ◽  
Katrina A. Jolliffe
Keyword(s):  
Total Synthesis ◽  
Natural Product ◽  
Side Chain ◽  
Linear Peptide ◽  
Cyclic Hexapeptide ◽  
Peptide Precursors ◽  
Head To Tail Cyclization

The total synthesis of cyclic hexapeptide dichotomin A from linear peptide precursors containing penicillamine-derived pseudoproline residues is reported. The incorporation of a pseudoproline residue led to a faster reaction and higher head-to-tail cyclization yields in comparison to linear precursors containing the native valine residue. However, deprotection of the pseudoproline resulted in significant amounts of a by-product in which a threonine side chain had undergone dehydration, resulting in a low overall yield of the natural product.

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