scholarly journals The Total Synthesis of Aigialomycin D and Analogues

2021 ◽  
Author(s):  
◽  
Lynton James Baird
Keyword(s):  
Total Synthesis ◽  
Biologically Active ◽  
Moderate Activity ◽  
Active Member ◽  
Biological Testing ◽  
Aromatic Fragment ◽  
New Family ◽  
The Family ◽  
Retrosynthetic Analysis ◽  
Synthetic Approaches

<p>In 2002 a new family of 14-membered resorcylic macrolides, the aigialomycins, were isolated from the mangrove fungus Aigialus parvus BCC 5311. Subsequent biological testing of these new natural products found aigialomycin D (Am D) to be the most biologically active member of the family, exhibiting moderate activity against malaria (Plasmodium falciparum K1, IC50 19.7 Mu) and modest cytotoxicity towards certain cancer cells (KB cells: IC50 9.0 Mu and BC-1 cells: 53.8 Mu). More recently, Am D has been shown to inhibit the kinases CDK1/5 and GSK at low Mu concentrations. At the onset of this research project, with only one total synthesis of Am D reported in the literature, there remained a need for an efficient synthesis of Am D that would be amenable to the synthesis of a range of analogues. This thesis reports two synthetic approaches to Am D that differ primarily in the chemistry utilised to install the (E)-olefins at C1'-C2' and C7'-C8': a Horner-Wadsworth-Emmons (HWE) strategy and a Ramberg-Backlund (RB) strategy. The Ramberg-Backlund strategy ultimately proved to be successful, providing Am D in 16 steps with 9% overall yield. A retrosynthetic analysis of Am D disconnects the molecule into three major fragments: an aromatic fragment, a C2'-C7' carbohydrate-derived fragment and a C8'-C11' alcohol fragment. The synthesis of the three fragments for each strategy is described and the attempts made to couple the fragments together, first with HWE methodology and then successfully with ring-closing metathesis (RCM) and RB reactions, are discussed. The synthesis of several Am D analogues and their preliminary biological testing is also described.</p>

scholarly journals The Total Synthesis of Aigialomycin D and Analogues

2021 ◽  
Author(s):  
◽  
Lynton James Baird
Keyword(s):  
Total Synthesis ◽  
Biologically Active ◽  
Moderate Activity ◽  
Active Member ◽  
Biological Testing ◽  
Aromatic Fragment ◽  
New Family ◽  
The Family ◽  
Retrosynthetic Analysis ◽  
Synthetic Approaches

<p>In 2002 a new family of 14-membered resorcylic macrolides, the aigialomycins, were isolated from the mangrove fungus Aigialus parvus BCC 5311. Subsequent biological testing of these new natural products found aigialomycin D (Am D) to be the most biologically active member of the family, exhibiting moderate activity against malaria (Plasmodium falciparum K1, IC50 19.7 Mu) and modest cytotoxicity towards certain cancer cells (KB cells: IC50 9.0 Mu and BC-1 cells: 53.8 Mu). More recently, Am D has been shown to inhibit the kinases CDK1/5 and GSK at low Mu concentrations. At the onset of this research project, with only one total synthesis of Am D reported in the literature, there remained a need for an efficient synthesis of Am D that would be amenable to the synthesis of a range of analogues. This thesis reports two synthetic approaches to Am D that differ primarily in the chemistry utilised to install the (E)-olefins at C1'-C2' and C7'-C8': a Horner-Wadsworth-Emmons (HWE) strategy and a Ramberg-Backlund (RB) strategy. The Ramberg-Backlund strategy ultimately proved to be successful, providing Am D in 16 steps with 9% overall yield. A retrosynthetic analysis of Am D disconnects the molecule into three major fragments: an aromatic fragment, a C2'-C7' carbohydrate-derived fragment and a C8'-C11' alcohol fragment. The synthesis of the three fragments for each strategy is described and the attempts made to couple the fragments together, first with HWE methodology and then successfully with ring-closing metathesis (RCM) and RB reactions, are discussed. The synthesis of several Am D analogues and their preliminary biological testing is also described.</p>

Synthetic approaches to [5,6]-benzannulated spiroketal natural products

2011 ◽  
Vol 84 (6) ◽  
pp. 1379-1390 ◽  
Author(s):  
Michael C. McLeod ◽  
Margaret A. Brimble ◽  
Dominea C. K. Rathwell ◽  
Zoe E. Wilson ◽  
Tsz-Ying Yuen
Keyword(s):  
Natural Products ◽  
Total Synthesis ◽  
Electronic Properties ◽  
Late Stage ◽  
Biologically Active ◽  
Formal Synthesis ◽  
Berkelic Acid ◽  
Synthetic Approaches

Studies toward the synthesis of three biologically active [5,6]-benzannulated spiroketal natural products are described. The first total synthesis of paecilospirone is reported, employing a late-stage, pH-neutral spiroketalization. A formal synthesis of γ-rubromycin is described, where the spiroketal moiety is formed by delicate manipulation of the electronic properties of the spirocyclization precursor. Finally, model work toward the total synthesis of berkelic acid is summarized, introducing a novel Horner–Wadsworth–Emmons/oxa-Michael (HWE/oxa-M) cascade to access the spiroketal precursor.

Three new species, two new genera, and new family Biphragmosagittidae (Сhaetognatha) from Southwest Pacific Ocean

2011 ◽  
Vol 20 (1) ◽  
pp. 161-173
Author(s):  
A.P. Kassatkina
Keyword(s):  
New Species ◽  
Type Species ◽  
Morphological Characters ◽  
The Body ◽  
New Order ◽  
New Genera ◽  
New Family ◽  
The Family ◽  
Three New Species

Resuming published and own data, a revision of classification of Chaetognatha is presented. The family Sagittidae Claus & Grobben, 1905 is given a rank of subclass, Sagittiones, characterised, in particular, by the presence of two pairs of sac-like gelatinous structures or two pairs of fins. Besides the order Aphragmophora Tokioka, 1965, it contains the new order Biphragmosagittiformes ord. nov., which is a unique group of Chaetognatha with an unusual combination of morphological characters: the transverse muscles present in both the trunk and the tail sections of the body; the seminal vesicles simple, without internal complex compartments; the presence of two pairs of lateral fins. The only family assigned to the new order, Biphragmosagittidae fam. nov., contains two genera. Diagnoses of the two new genera, Biphragmosagitta gen. nov. (type species B. tarasovi sp. nov. and B. angusticephala sp. nov.) and Biphragmofastigata gen. nov. (type species B. fastigata sp. nov.), detailed descriptions and pictures of the three new species are presented.

An Overview on Phytochemical and Pharmacological Profile of Morus alba Linn.

2020 ◽  
Vol 16 ◽  
Author(s):  
Arpita Paul ◽  
Monami Rajiung ◽  
Kamaruz Zaman ◽  
Sushil Kumar Chaudhary ◽  
Hans Raj Bhat ◽  
...  
Keyword(s):  
Traditional Medicine ◽  
Morus Alba ◽  
Biologically Active ◽  
Pharmacological Profile ◽  
Pharmacological Activities ◽  
Significant Information ◽  
The Past ◽  
Comprehensive Information ◽  
The Family ◽  
White Mulberry

Background: Morus alba Linn. commonly known as white mulberry, belongs to the family Moraceae, is a promising traditional medicine. In Asia, besides its use in the preparation of delicacies, every part of this plant is utilized in traditional medicine. Over the past decade, studies related to identification and isolation of biologically active compounds, with flavonoids as the major class of phytoconstituents, from this plant has been reported. These phytoconstituents are not only found to be beneficial for the maintenance of general health but also are associated with a range of potential pharmacological activities such as antioxidant, anti-inflammatory, anti-diabetic, anticancer, hepatoprotective, cardioprotective, neuroprotective to name a few. Objective: This review aims to provide upgraded and comprehensive information regarding the phytochemical, ethnomedicinal use and pharmacological profile of the plant Morus alba Linn. Method: The significant information has been collected through various database viz. PubMed, Scopus, Web of Science, Science Direct based on the recent findings, using different terms of Morus alba. Results: The outcome of the study suggests that Morus alba is a multifunctional plant numerous phytochemicals, and possess a range of pharmacological activities. Conclusion: The data assembled on Morus alba will be beneficial to trigger research in various fields of pharmaceutical and allied science to explore the medicinal importance of this unique plant.

Correcting a 135-year error: Limulidae Leach, 1819 (Chelicerata, Xiphosura) is the proper authority, not Limulidae Zittel, 1885

2021 ◽  
pp. 1-2
Author(s):  
Philip M. Novack-Gottshall ◽  
Roy E. Plotnick
Keyword(s):  
Horseshoe Crab ◽  
Marine Species ◽  
Limulus Polyphemus ◽  
Junior Synonym ◽  
Living Fossil ◽  
New Family ◽  
The Family ◽  
The World ◽  
Modern Genus

The horseshoe crab Limulus polyphemus (Linnaeus, 1758) is a famous species, renowned as a ‘living fossil’ (Owen, 1873; Barthel, 1974; Kin and Błażejowski, 2014) for its apparently little-changed morphology for many millions of years. The genus Limulus Müller, 1785 was used by Leach (1819, p. 536) as the basis of a new family Limulidae and synonymized it with Polyphemus Lamarck, 1801 (Lamarck's proposed but later unaccepted replacement for Limulus, as discussed by Van der Hoeven, 1838, p. 8) and Xyphotheca Gronovius, 1764 (later changed to Xiphosura Gronovius, 1764, another junior synonym of Limulus). He also included the valid modern genus Tachypleus Leach, 1819 in the family. The primary authority of Leach (1819) is widely recognized in the neontological literature (e.g., Dunlop et al., 2012; Smith et al., 2017). It is also the authority recognized in the World Register of Marine Species (WoRMS Editorial Board, 2021).

Early Paleozoic Hyolitha from North America: reexamination of Walcott's and Resser's type specimens

1988 ◽  
Vol 62 (2) ◽  
pp. 218-233 ◽  
Author(s):  
John Mark Malinky
Keyword(s):  
North America ◽  
Lower Cambrian ◽  
Type Species ◽  
New Genus ◽  
Early Paleozoic ◽  
Type Specimens ◽  
Middle Cambrian ◽  
Upper Cambrian ◽  
New Family ◽  
The Family

Concepts of the family Hyolithidae Nicholson fide Fisher and the genera Hyolithes Eichwald and Orthotheca Novak have been expanded through time to encompass a variety of morphologically dissimilar shells. The Hyolithidae is here considered to include only those hyolithid species which have a rounded (convex) dorsum; slopes on the dorsum are inflated, and the venter may be flat or slightly inflated. Hyolithes encompasses species which possess a low dorsum and a prominent longitudinal sulcus along each edge of the dorsum; the ligula is short and the apertural rim is flared. The emended concept of Orthotheca includes only those species of orthothecid hyoliths which have a subtriangular transverse outline and longitudinal lirae covering the shell on both dorsum and venter.Eighteen species of Hyolithes and one species of Orthotheca from the Appalachian region and Western Interior were reexamined in light of more modern taxonomic concepts and standards of quality for type material. Reexamination of type specimens of H. similis Walcott from the Lower Cambrian of Newfoundland, H. whitei Resser from the Lower Cambrian of Nevada, H. billingsi Walcott from the Lower Cambrian of Nevada, H. gallatinensis Resser from the Upper Cambrian of Wyoming, and H. partitus Resser from the Middle Cambrian of Alabama indicates that none of these species represents Hyolithes. Hyolithes similis is here included under the new genus Similotheca, in the new family Similothecidae. Hyolithes whitei is designated as the type species of the new genus Nevadotheca, to which H. billingsi may also belong. Hyolithes gallatinensis is referred to Burithes Missarzhevsky with question, and H. partitus may represent Joachimilites Marek. The type or types of H. attenuatus Walcott, H. cecrops Walcott, H. comptus Howell, H. cowanensis Resser, H. curticei Resser, H. idahoensis Resser, H. prolixus Resser, H. resseri Howell, H. shaleri Walcott, H. terranovicus Walcott, and H. wanneri Resser and Howell lack shells and/or other taxonomically important features such as a complete aperture, rendering the diagnoses of these species incomplete. Their names should only be used for the type specimens until better preserved topotypes become available for study. Morphology of the types of H.? corrugatus Walcott and “Orthotheca” sola Resser does not support placement in the Hyolitha; the affinities of these species are uncertain.

scholarly journals Amino acid residues modulating the activities of staphylococcal glutamyl endopeptidases

2010 ◽  
Vol 391 (10) ◽  
Author(s):  
Toshio Ono ◽  
Yuko Ohara-Nemoto ◽  
Yu Shimoyama ◽  
Hisami Okawara ◽  
Takeshi Kobayakawa ◽  
...  
Keyword(s):  
Family Members ◽  
Glutamyl Endopeptidase ◽  
Peptidase Activity ◽  
Amino Acid Residues ◽  
Virulence Determinants ◽  
Cloning And Sequencing ◽  
New Family ◽  
The Family ◽  
N Terminus ◽  
Staphylococcus Epidermis

AbstractThe glutamyl endopeptidase family of enzymes from staphylococci has been shown to be important virulence determinants of pathogenic family members, such asStaphylococcus aureus. Previous studies have identified the N-terminus and residues from positions 185–195 as potentially important regions that determine the activity of three members of the family. Cloning and sequencing of the new family members fromStaphylococcus caprae(GluScpr) andStaphylococcus cohnii(GluScoh) revealed that the N-terminal Val residue is maintained in all family members. Mutants of the GluV8 enzyme fromS. aureuswith altered N-terminal residues, including amino acids with similar properties, were inactive, indicating that the Val residue is specifically required at the N-terminus of this enzyme family in order for them to function correctly. Recombinant GluScpr was found to have peptidase activity intermediate between GluV8 and GluSE fromStaphylococcus epidermisand to be somewhat less specific in its substrate requirements than other family members. The 185–195 region was found to contribute to the activity of GluScpr, although other regions of the enzyme must also play a role in defining the activity. Our results strongly indicate the importance of the N-terminal and the 185–195 region in the activity of the glutamyl endopeptidases of staphylococci.

Palaeonema phyticum gen. n., sp. n. (Nematoda: Palaeonematidae fam. n.), a Devonian nematode associated with early land plants

Nematology ◽  
2008 ◽  
Vol 10 (1) ◽  
pp. 9-14 ◽  
Author(s):  
George Poinar Jr ◽  
Hans Kerp ◽  
Hagen Hass
Keyword(s):  
Early Stage ◽  
Land Plant ◽  
Terrestrial Plants ◽  
Early Devonian ◽  
Plant Parasitism ◽  
New Family ◽  
The Earth ◽  
The Family ◽  
The Face ◽  
Early Land

AbstractNematodes are one of the most abundant groups of invertebrates on the face of the earth. Their extremely poor fossil record hinders our ability to assess just when members of this group invaded land and first became associated with plants. This study reports fossil nematodes from the stomatal chambers of the Early Devonian (396 mya) land plant, Aglaophyton major. These nematodes, which are tentatively assigned to the order Enoplia, are described as Palaeonema phyticum gen. n., sp. n. in the new family Palaeonematidae fam. n. Diagnostic characters of the family are: i) cuticular striations; ii) uniform, cylindrical pharynx with the terminal portion only slightly set off from the remainder; and iii) a two-portioned buccal cavity with the upper portion bearing protuberances. The presence of eggs, juveniles and adults in family clusters within the plant tissues provide the earliest evidence of an association between terrestrial plants and animals and may represent an early stage in the evolution of plant parasitism by nematodes.

Applanodictyosporous Pleosporales: Clathrospora, Comoclathris, GraphyIlium, Macrospora, and Platysporoides

1992 ◽  
Vol 70 (8) ◽  
pp. 1617-1658 ◽  
Author(s):  
R. A. Shoemaker ◽  
C. E. Babcock
Keyword(s):  
Key Words ◽  
New Genus ◽  
New Family ◽  
The Family

Six genera of the order Pleosporales are revised taxonomically. Although five genera have unusual applanate ascospores, they are members of three different families. Clathrospora (10 species, 2 new), Comoclathris (21 species, 7 new), and Macrospora (3 species) are placed in a new family Diademaceae in which the ascoma opening is a characteristic flat circular lid. Diademosa, a new genus with one species with terete ascospores is placed in Diademaceae. Graphyllium (3 species) is placed in the family Hysteriaceae characterized by hysterothecia with a slit-like opening. Platysporoides n.gen. (11 species, 1 new) is maintained in the Pleosporaceae because of the terete pored beak of the ascomata. Key words: Pleosporales, applanate ascospores, Clathrospora, Comoclathris, Macrospora, Diademosa, Graphyllium, Platysporoides.

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