Enantioselectivity of hydroxylation of racemic piperitone by fungi

Abstract

The biotransformation of racemic piperitone ((±)-1) was investigated using four strains of fungi selected in the screening procedure. The substrate was transformed by Botrytis cinerea AM235, Absidia cylindrospora AM336, Absidia coerulea AM93, and Absidia glauca AM177 into more polar metabolites. The transformation of racemic piperitone ((±)-1) catalyzed by B. cinerea AM235 gave 7-hydroxypiperitone (2) as the only product. The biotransformation of (±)-1 by A. cylindrospora AM336 afforded mixture of three products: (-)-(R)-7-hydroxypiperitone ((-)-2), (+)-(4S,6R)-trans-6-hydroxypiperitone ((+)-3), and (+)-(4R,6R)-cis-6-hydroxypiperitone ((+)-4). The transformation of this substrate ((±)-1) by A. coerulea AM93 gave (±)-7-hydroxypiperitone ((±)-2), (-)-(4R,6S)-trans-6-hydroxypiperitone (-)-3), and (-)-(4S,6S)-cis-6-hydroxypiperitone ((-)-4). The last strain studied, A. glauca AM177, converted racemic piperitone ((±)-1) to four products: (+)-(S)-7-hydroxypiperitone (2), (+)-(4S,6R)-trans-6-hydroxypiperitone ((+)-3), (±)-cis-6-hydroxypiperitone ((±)-4), and 8-hydroxypiperitone (5).

Improved dialytic removal of protein-bound uraemic toxins with use of albumin binding competitors: an in vitro human whole blood study

“…The binding of a given ligand on albumin may alter the conformation in the vicinity of the binding sites, or directly block the diffusion path for binding of other ligands. The binding competition between different albumin ligands has been widely reported in the literature 18 19 21 22 23 24 25 . Using compounds that share the same binding sites as uraemic toxins to impede their binding is a direct approach to increase the free fraction of these uraemic toxins.…”

Natural Product Diversification by One‐Step Biocatalysis using Human P450 3A4

“…By comparing to literature 1 H NMR data of both trans-and cis-6-hydroxypiperitone isomers, which show different chemical shifts due to the hydroxyl group sitting either in a pseudoaxial (trans to isopropyl) or -equatorial (cis to isopropyl) position, the formed product structure was suggested to be trans-6-hydroxypiperitone. [143,144] (+)-nootkatone ( (75), 79 (69), 67 (25), 53 (25), 41 (50). 8 Hz, 9-H), 2.64 (1H, dddd, J = 12.7, 12.6 3.2, 2.7 Hz, 7-H), 2.24 (1H, dd, J = 16.9, 14.0 Hz, 3α-H), 2.12 (1H, dd, J = 16.9, 4.0 Hz, 3β-H), 1.92-1.85 (2H, m, 4-, 8α-H), 1.84 (1H, ddd, J = 13.1, 3.1, 3.0 Hz, 6α-H), 1.62 (3H, br, 13-H), 1.37 (1H, ddd, J = 13.1, 12.9, 3.0, 8β-H), 1.17 (3H, br, 15-H), 0.95 (1H, dd, J = 12.9, 12.8 Hz, 6β-H), 0.82 (3H, d, J = 6.8 Hz, 14-H); GC-MS (EI + , 70 eV): m/z (%) = 234 ([M] + , 25), 216 (88), 191 (100), 174 (31), 166 (31), 159 (31), 145 (38), 137 (50), 131 (31), 121 (38), 107 (38), 91 (38), 67 (38), 55 (25), 41 (44).…”

Ulleungamides A and B, Modified α,β-Dehydropipecolic Acid Containing Cyclic Depsipeptides from Streptomyces sp. KCB13F003

“…Ulleungamide B (2) was isolated as a white powder, and the HRESIMS analysis showed an ion peak at m/z 1024.4642 [M + Na] + (C 51 H 67 N 7 O 14 , calcd for C 51 H 67 N 7 O 14 Na, 1024.4644). The 1 H and 13 C NMR spectra similar to those of 1, together with an additional 16 amu, suggested that 2 is likely the hydroxy derivative of 1. The 2D NMR analysis clearly revealed that the methylene group C-4 was replaced by the oxygenated methine group (δ C 62.9, δ H 4.16), indicating the presence of 4,5dihydroxy-6-methyl-2,3-dehydropipecolic acid (DHMDPA).…”

“…Pipecolic acid, cyclic nonproteogenic amino acid, is a key constituent of numerous pharmaceutically important secondary metabolites, such as rapamycin and FK506. 13 Sandramycin, quinaldopeptin, and petriellin A also have been reported to possess multiple pipecolic acids, 14 but ulleungamides are the first example of having three residues of Pip and Pip derivatives. The peptide metabolites that contain the γ-OH-Pip residue are quite rare with only two examples, which were found in virginiamycin S 5 and MBJ-0110.…”

“…They contain multiple pipecolic acid-derived residues, including Pip, γ-OH-Pip, HMDPA, and DHMDPA. Pipecolic acid, cyclic nonproteogenic amino acid, is a key constituent of numerous pharmaceutically important secondary metabolites, such as rapamycin and FK506 . Sandramycin, quinaldopeptin, and petriellin A also have been reported to possess multiple pipecolic acids, but ulleungamides are the first example of having three residues of Pip and Pip derivatives.…”