Publications by authors named "Gints Smits"

7 Publications

  • Page 1 of 1

Total Synthesis of the Proposed Structure of Uncarialin A.

J Org Chem 2021 May 21;86(9):6927-6930. Epub 2021 Apr 21.

Latvian Institute of Organic Synthesis, Aizkraukles 21, LV-1006 Riga, Latvia.

The stereoselective total synthesis of the proposed structure of a potent serotonin 5-HT receptor agonist uncarialin A () is described. By employing the readily available meroquinene -butyl ester as the chiral synthon, the target structure has been prepared in a six-step linear sequence with a 17% overall yield. In comparison to the sample isolated from natural sources, the synthetic product shows significant spectral differences, strongly suggesting that the structure of the natural product should be revised.
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http://dx.doi.org/10.1021/acs.joc.1c00324DOI Listing
May 2021

Isolation, chemistry, and biology of pyrrolo[1,4]benzodiazepine natural products.

Med Res Rev 2021 Apr 13. Epub 2021 Apr 13.

Latvian Institute of Organic Synthesis, Riga, Latvia.

The isolation of the antitumor antibiotic anthramycin in the 1960s prompted extensive research into pyrrolo[1,4]benzodiazepines (PBD) as potential therapeutics for the treatment of cancers. Since then, nearly 60 PBD natural products have been isolated and evaluated with regard to their biological activity. Synthetic studies and total syntheses have enabled access to PBD analogues, culminating in the development of highly potent anticancer agents. This review provides a summary of the occurrence and biological activity of PBD natural products and covers the strategies employed for their total syntheses.
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http://dx.doi.org/10.1002/med.21803DOI Listing
April 2021

First Total Synthesis and in Vitro Cytotoxicities of Flavesines G and J.

ACS Omega 2020 Jun 19;5(21):12568-12572. Epub 2020 May 19.

Latvian Institute of Organic Synthesis, Aizkraukles 21, Riga LV-1006, Latvia.

The first total synthesis of flavesines G and J, natural products exhibiting antiviral activity against hepatitis B virus, is described. A robust, protecting-group-free route starting from commercially available natural product 9-azajulolidine allowed us to obtain the title compounds in a four- and five-step sequence accordingly. Flavesines G and J exhibit micromolar cytotoxicity in A549, MCF-7, HepG2, PANC-1, and HL-60 cancer cell lines.
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http://dx.doi.org/10.1021/acsomega.0c01672DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7271405PMC
June 2020

Stereoselective synthesis of an eleganine A core.

Org Biomol Chem 2020 06;18(24):4566-4568

Latvian Institute of Organic Synthesis, Aizkraukles 21, Riga, LV-1006, Latvia.

A synthetic approach towards the core of a structurally unique cytotoxic indole alkaloid eleganine A has been accomplished for the first time. The synthesis features a stereoselective Ireland-Claisen rearrangement as the key step, enabling the installation of 2 stereogenic centers and a stereodefined double bond in a single step. Furthermore, a SnCl4 promoted acylation of the indole C-2 position allows the coupling of a highly functionalized 4-ethylidene proline fragment with the indole part.
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http://dx.doi.org/10.1039/d0ob00939cDOI Listing
June 2020

Total synthesis and evaluation of 8-deoxypumiliotoxin 193H.

Nat Prod Res 2021 Feb 2;35(3):440-446. Epub 2019 Jul 2.

Latvian Institute of Organic Synthesis, Riga, Latvia.

The total synthesis of both the double bond isomers of indolizine alkaloid 8-deoxypumiliotoxin 193H has been accomplished. Both the double bond isomers Z-4 and E-4 induced convulsions and inhibited neuro-muscular activity at a dose of 25 mg/kg after intraperitoneal injection in mice. The lethal dose of Z-4 and E-4 was 100 mg/kg, indicating that 8-deoxypumiliotoxin 193H is 10-times less toxic than the known pumiliotoxin (+)-251 D.
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http://dx.doi.org/10.1080/14786419.2019.1636244DOI Listing
February 2021

Modified Julia-Kocienski Reagents for a Stereoselective Introduction of Trisubstituted Double Bonds: A Formal Total Synthesis of Limazepine E and Barmumycin.

J Org Chem 2018 05 18;83(9):5323-5330. Epub 2018 Apr 18.

Latvian Institute of Organic Synthesis , Aizkraukles 21 , Riga LV-1006 , Latvia.

A formal total synthesis of pyrrolo[1,4]benzodiazepine anticancer antibiotic family member limazepine E is described. The synthesis features a stereoselective introduction of a trisubstituted double bond using novel sterically demanding Julia-Kocienski reagents, allowing the number of linear steps to be significantly reduced. The potential of the newly developed reagents has also been demonstrated by the formal total synthesis of barmumycin.
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http://dx.doi.org/10.1021/acs.joc.8b00643DOI Listing
May 2018

The exocyclic olefin geometry control via Ireland-Claisen rearrangement: stereoselective total syntheses of Barmumycin and Limazepine E.

Org Lett 2013 Sep 21;15(17):4406-9. Epub 2013 Aug 21.

Latvian Institute of Organic Synthesis, Aizkraukles 21, LV-1006, Riga, Latvia.

Stereoselective total syntheses of Limazepine E and Barmumycin, potent, naturally occurring antitumor agents, are described. The total syntheses control the olefin geometry via a highly selective chelation-controlled Ireland-Claisen rearrangement of a seven-membered lactone-derived boron enolate for the synthesis of (E)-4-ethylidene proline, a crucial building block for a number of natural products.
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http://dx.doi.org/10.1021/ol4019453DOI Listing
September 2013