First Total Synthesis of Astechrome : Novel Hydroxamic Acid with an Indole-Pyrazine Skeleton

Astechrome (1), isolated from Aspergillus terreus IFO 6123 and 8835, was synthesized. Indolylmagnesium bromide (4) was coupled with a chloromethylpyrazine (5) to give 2-chloro-5-methoxy-3-methyl-6-[7-(3-methyl-2-butenyl)indol-3-yl]methylpyrazine 1-oxide (6), which was converted to the Fe salt (9) of a hydroxamic acid derivative (8). Oxidation of 9 with Co(salen) afforded 1.