Microbiological Hydroxylation at Eight Individual Carbon Atoms of Marcfortine A

Abstract

Hydroxylation of the indole alkaloid marcfortine A (1) at carbon atoms 5, 10, 12, 14, 15, 16, and 27 was realized by various soil-derived microorganisms. Fission at the C-12−N bond was also observed. The structural elucidation of the products (2 − 12) was accomplished by spectroscopic and semisynthetic means.

Simple indole alkaloids and those with a nonrearranged monoterpenoid unit (July 1997 to December 1998)

“…Lee and co-workers have studied the oxidation of the fungal metabolite marcfortine A 104 162 and were able to hydroxylate this alkaloid microbiologically at eight individual carbon atoms. 163 Derivatives of marcfortine A 104 were prepared to test their anthelmintic activity. 164 A new ring contraction reaction has been employed for converting marcfortine A to paraherquamides.…”

Chrysogenamide A from an Endophytic Fungus Associated with Cistanche deserticola and Its Neuroprotective Effect on SH-SY5Y Cells

“…Interpretation of HMBC correlations (Fig. 2) indicated the presence of partial structure A (HMBC correlations 1-NH to C-8 and C-9; H-6 to C-26; H-5 to C-7 and C-9; H-26 to C-28 and C-8 and H-27 to C-29 and C-30) and B (HMBC correlations H-10 to C-3, C-22, C-21, C-11, C-12; H-20 to C-13, C-18, C-22, C-11 and 19-NH to C-13, C-10), and C, a six membered G ring [8] with a methylated carbon at C-17 (HMBC correlations H-23 to C-17, C-16). The connectivity of substructure A to B through C-3 was supported by the key HMBC correlations from H-4 and 1-NH to C-3; H-10 to C-2 and C-9.…”

Asymmetric synthesis of chiral 1,2-oxazinane and hexahydropyridazin spirocyclic scaffolds by organocatalytic [4 + 2] cycloaddition

“…Spiro-oxindole scaffolds bearing a quaternary carbon stereocenter at the 3-position, especially with a heterocycle, are privileged and wide-spread among natural products and medicinal compounds. 1 Among the vast array of spiro-oxindole scaffolds, these structures which contain two heteroatoms at the spiro ring are of great importance due to their remarkable bioactivites ( Fig. 1 ).…”