62722-99-0Relevant academic research and scientific papers
A facile synthesis and enzymatic resolution of naturally occurring remotely functionalized alkylmethylmaleic anhydrides from Aspergillus wentii: Aspergillus acids A-D
Easwar, Srinivasan,Argade, Narshinha P.
, p. 831 - 838 (2007/10/03)
The first synthesis of four new naturally occurring remotely functionalized secondary mould metabolite anhydrides 1a-d is described starting from N-p-tolyl citraconimide (5) in three to six steps and 20-65% overall yields. The condensation of triphenylphosphine-maleimide adduct 6 with aldehyde 4 furnished the exoimide 7, which after isomerization, hydrolysis, and acylation gave aspergillus acid A (1a) in 54% overall yield in four steps. The condensation of adduct 6 with aldehyde 15 similarly afforded the desired imide 17 in two steps. The acid-catalyzed hydrolysis of imide 17 directly furnished aspergillus acid B (1b), exposing the latent methyl ketone present as the terminal acetylene. Sodium borohydride induced chemoselective reduction of aspergillus acid B (1b) gave aspergillus acid C (1c), which upon acetic anhydride induced acylation, furnished aspergillus acid D (1d). A facile Amano PS catalyzed acylation of aspergillus acid C (1c) gave, in good yield, the desired (+)-aspergillus acid C (1e) in 70% ee and (-)-aspergillus acid D (1f) in 72% ee. In the present enzymatic reaction, the anhydride moiety presumably plays a crucial role in the substrate recognition, binding, and resolution process. Georg Thieme Verlag Stuttgart.
