Organic synthesis is a special branch of chemical synthesis and is concerned with the intentional construction of organic compounds. Organic molecules are often more complex than inorganic compounds, and their synthesis has developed into one of the most important branches of organic chemistry. There are several main areas of research within the general area of organic synthesis: total synthesis, semisynthesis, and methodology.
Enantioselective synthesis, also called asymmetric synthesis, is a form of chemical synthesis. It is defined by IUPAC as: a chemical reaction in which one or more new elements of chirality are formed in a substrate molecule and which produces the stereoisomeric products in unequal amounts.
Fumagillin is a complex biomolecule and used as an antimicrobial agent. It was isolated in 1949 from the microbial organism Aspergillus fumigatus.
Biocatalysis refers to the use of living (biological) systems or their parts to speed up (catalyze) chemical reactions. In biocatalytic processes, natural catalysts, such as enzymes, perform chemical transformations on organic compounds. Both enzymes that have been more or less isolated and enzymes still residing inside living cells are employed for this task. Modern biotechnology, specifically directed evolution, has made the production of modified or non-natural enzymes possible. This has enabled the development of enzymes that can catalyze novel small molecule transformations that may be difficult or impossible using classical synthetic organic chemistry. Utilizing natural or modified enzymes to perform organic synthesis is termed chemoenzymatic synthesis; the reactions performed by the enzyme are classified as chemoenzymatic reactions.
Gliotoxin is a sulfur-containing mycotoxin that belongs to a class of naturally occurring 2,5-diketopiperazines produced by several species of fungi, especially those of marine origin. It is the most prominent member of the epipolythiopiperazines, a large class of natural products featuring a diketopiperazine with di- or polysulfide linkage. These highly bioactive compounds have been the subject of numerous studies aimed at new therapeutics. Gliotoxin was originally isolated from Gliocladium fimbriatum, and was named accordingly. It is an epipolythiodioxopiperazine metabolite.
Spirotryprostatin B is an indolic alkaloid found in the Aspergillus fumigatus fungus that belongs to a class of naturally occurring 2,5-diketopiperazines. Spirotryprostatin B and several other indolic alkaloids have been found to have anti-mitotic properties, and as such they have become of great interest as anti-cancer drugs. Because of this, the total syntheses of these compounds is a major pursuit of organic chemists, and a number of different syntheses have been published in the chemical literature.
Spirotryprostatin A is an indolic alkaloid from the 2,5-Diketopiperazine class of natural products found in the Aspergillus fumigatus fungus. Spirotryprostatin A and several other indolic alkaloids have been found to have anti-mitotic properties, and as such they have become of great interest as anti-cancer drugs. Because of this, the total syntheses of these compounds is a major pursuit of organic chemists, and a number of different syntheses have been published in the chemical literature.
Brevianamides are indole alkaloids that belong to a class of naturally occurring 2,5-diketopiperazines produced as secondary metabolites of fungi in the genus Penicillium and Aspergillus. Structurally similar to paraherquamides, they are a small class compounds that contain a bicyclo[2.2.2]diazoctane ring system. One of the major secondary metabolites in Penicillium spores, they are responsible for inflammatory response in lung cells.
Synthesis of morphine-like alkaloids in chemistry describes the total synthesis of the natural morphinan class of alkaloids that includes codeine, morphine, oripavine, and thebaine and the closely related semisynthetic analogs methorphan, buprenorphine, hydromorphone, hydrocodone, isocodeine, naltrexone, nalbuphine, oxymorphone, oxycodone, and naloxone.
Phenylahistin is a metabolite produced by the fungus Aspergillus ustus that belongs to a class of naturally occurring 2,5-diketopiperazines featuring a dehydrohistidine residue that exhibit important biological activities, such as anti-cancer or neurotoxic effects.
Secalonic acids are a group of chiral dimeric tetrahydroxanthones closely related to ergoflavin and ergochrysin A that are collectively called ergochromes and belong to a class of mycotoxins initially isolated as major ergot pigments from the fungi Claviceps purpurea that grows parasitically on rye grasses. From early times and particularly in medieval Europe the consumption of grains containing ergot has repeatedly lead to mass poisonings known as ergotism which was caused by toxic ergot alkaloids and mycotoxins such as the ergochromes, due to contamination of flour by C. purpurea. A cluster of genes responsible for the synthesis of secalonic acids in C. purpurea has been identified. Secalonic acid D the enantiomer of secalonic acid A is a major environmental toxin, isolated from the fungus Penicillium oxalicum, and is a major microbial contaminant of freshly-harvested corn which causes toxicity through contamination of foodstuffs.
Fumitremorgins are tremorogenic metabolites of Aspergillus and Penicillium, that belong to a class of naturally occurring 2,5-diketopiperazines.
Fellutamide A and B are tripeptide derivatives from Penicillium fellutanum and other fungi. They are potent proteasome inhibitor that stimulates nerve growth factor synthesis in vitro. It strongly inhibits the growth of the tuberculosis-causing bacterium Mycobacterium tuberculosis. Its biosynthetic pathway has been determined in the filamentous fungus Aspergillus nidulans.
Fellutanine A, B, C and D are bio-active diketopiperazine alkaloids isolated from the cultures of Penicillium fellutanum, that belongs to a class of naturally occurring 2,5-diketopiperazines. Originally they were thought to be based on the "trans" cyclic dipetide cyclo(L-Trp-D-Trp) but were later shown to be based on the "cis" cyclic dipetide cyclo(L-Trp-L-Trp). This was also confirmed when fellutanine A, B and C were isolated from Penicillium simplicissimum. The fellutanines A−C, are non-annulated analogues of cyclo(L-Trp-L-Trp), but unlike their diannulated analogue fellutanine D are not cytotoxic.
Verruculogen is a mycotoxin produced by certain strains of aspergillus that belongs to a class of naturally occurring 2,5-diketopiperazines. It is an annulated analogue of cyclo(L-Trp-L-Pro) which belongs to the most abundant and structurally diverse class of tryptophan-proline 2,5-diketopiperazine natural products. It produces tremors in mice due to its neurotoxic properties. It also tested positive in a Salmonella/mammalian microsome assay and was shown to be genotoxic. It is a potent blocker of calcium-activated potassium channels.
Notoamides are bio-active isolates of marine Aspergillus.
Stephacidin A and B are antitumor alkaloids isolated from the fungus Aspergillus ochraceus that belong to a class of naturally occurring 2,5-diketopiperazines. This unusual family of fungal metabolites are complex bridged 2,5-diketopiperazine alkaloids that possess a unique bicyclo[2.2.2]diazaoctane core ring system and are constituted mainly from tryptophan, proline, and substituted proline derivatives where the olefinic unit of the isoprene moiety has been formally oxidatively cyclized across the α-carbon atoms of a 2,5-diketopiperazine ring. The molecular architecture of stephacidin B, formally a dimer of avrainvillamide, reveals a complex dimeric prenylated N-hydroxyindole alkaloid that contains 15 rings and 9 stereogenic centers and is one of the most complex indole alkaloids isolated from fungi. Stephacidin B rapidly converts into the electrophilic monomer avrainvillamide in cell culture, and there is evidence that the monomer avrainvillamide interacts with intracellular thiol-containing proteins, most likely by covalent modification.
Dideoxyverticillin A, also known as (+)-11,11’-dideoxyverticillin A, is a complex epipolythiodioxopiperazine initially isolated from the marine fungus Penicillium sp. in 1999. It has also been found in the marine fungus Bionectriaceae, and belongs to a class of naturally occurring 2,5-diketopiperazines.
Brevianamide F , also known as cyclo-(L-Trp-L-Pro), belongs to a class of naturally occurring 2,5-diketopiperazines. It is the simplest member and the biosynthetic precursor of a large family of biologically active prenylated tryptophan-proline 2,5-diketopiperazines that are produced by the fungi A.fumigates and Aspergillus sp. It has been isolated from the bacterium Streptomyces sp. strain TN58 and shown to possess activity against two Gram-positive bacteria, S.aureus and Micrococcus luteus, and has also been isolated from Bacillus cereus associated with the entomopathogenic nematode, Rhabditis (Oscheius) sp. and shown to have antifungal activity against T. rubrum, C. neoformans and C. albicans, better than amphotericin B. Although the proline 2,5-diketopiperazines are the most abundant and structurally diverse 2,5-diketopiperazines found in food, cyclo(L-Trp-L-Pro) has only been found as a minor 2,5-diketopiperazine (8.2ppm) in autolyzed yeast extract. Initially cyclo(L-Trp-L-Pro) and its DL, LD, and DD isomers showed potential for use in the treatment of cardiovascular dysfunction, however they were later shown to be hepatoxic.
Bicyclomycin (Bicozamycin) is a broad spectrum antibiotic active against Gram-negative bacteria and the Gram-positive bacterium, Micrococcus luteus that was isolated from Streptomyces sapporonesis and Streptomyces aizumenses in 1972. It belongs to a class of naturally occurring 2,5-diketopiperazines, that are among the most numerous of all the naturally occurring peptide antibiotics. This clinically useful antibiotic is rapidly absorbed in humans when given intramuscularly, has low toxicity and has been used to treat diarrhea in humans and bacterial diarrhea in calves and pigs.
