Photochemical oxazole–nitrile conversion downstream of rhizoxin biosynthesis and its impact on antimitotic activity

Burkholderia as a Source of Natural Products

“…More complex host associations involving three players have also been reported, including an interesting association that was described between a rice pathogenic fungus ( Rhizopus sp.) and a Burkholderia species that lives inside of the fungus (endosymbiont) and produces the polyketide precursor of rhizoxin, a phytotoxin that binds β-tubulin of rice cells, causing cell cycle arrest. − …”

Nitrile biosynthesis in nature: how and why?

“…For the transformation mechanism, it was proposed that a cycloaddition of singlet oxygen to an oxazole ring would yield a reactive peroxide, which further undergoes rearrangement to generate the nitrile group. 196…”

“…For the transformation mechanism, it was proposed that a cycloaddition of singlet oxygen to an oxazole ring would yield a reactive peroxide, which further undergoes rearrangement to generate the nitrile group. 196 Furthermore, a two-step two-electron reduction of nifurtimox, a prodrug for Chagas disease, yields the corresponding nitrile derivative by Trypanosoma cruzi and Trypanosoma brucei type I nitroreductase. Type I nitroreductases are NAD(P)Hdependent and FMN-binding proteins rare in most eukaryotes but abundantly expressed in trypanosomes.…”

Muscarine, imidazole, oxazole and thiazole alkaloids

“…Through metabolic proling of the mutants and wild type of the endofungal bacterium Burkholderia rhizoxinica, the oxazolyl moiety in rhizoxin was biotransformed into the nitrile group by photochemical oxidative cleavage. 180 The resulting nitriles showed signicantly less antimitotic activity than that of the parent compounds.…”