Synthesis of N-Acetyl-3-phenylisoserinates of Sesquiterpenoid Alcohols of Lactarius Origin

Abstract

Important biological properties of Taxol i.e. 13-N-benzoyl-(2R,3S)-3-phenylisoserinate of baccatin III and also N-benzoyl-(2R,3S)-3-phenylisoserinates of several sesquiterpenoid alcohols of Lactarius origin prompted us to synthesize N-acetyl-3-phenylisoserinates of latter alcohols in order to check and compare their biological properties. Suitably protected phenylisoserine 5 when reacted with sesquiterpenoid alcohols in the presence of DCC gave appropriate esters 7. These, after catalytic hydrogenation deprotection produced aminols 8, which were acetylated and gave the required N-acetyl-3-phenylisoserinates 9a-9g.

Alkyl 4-Chlorobenzoyloxycarbamates as Highly Effective Nitrogen Source Reagents for the Base-Free, Intermolecular Aminohydroxylation Reaction

“…We observed a discrepancy between our specific rotation value of −1.3 ( c 0.85, EtOH) [and −2.7 ( c 1.15, CHCl 3 )] for (−)- 22a (Table ) and that of +4.4 ( c 0.32, EtOH) reported by Sharpless et al On the other hand, our result was in closer agreement with the value of −3.79 ( c 1.0, CHCl 3 ) obtained by Barycki et al To corroborate our assignments, we obtained crystal structures of (−)- 22a and (−)- 23a using copper K-α X-radiation. The expected absolute configurations are apparent with probabilities of incorrect assignment of less than 0.4% and 0.01%, respectively.…”

“…Following the general AA procedure above, trans -methyl cinnamate (128 mg, 0.79 mmol) was reacted with osmium tetraoxide (8 mg, 32 μmol), (DHQ) 2 PHAL (31 mg, 0.039 mmol), and benzyl reagent 8 (337 mg, 1.10 mmol) at 0 °C. Subsequent flash column chromatography (silica gel, petroleum spirit/ethyl acetate 6:1 and 3:1) afforded (−) -22a as a colorless crystalline solid (159 mg, 61%): mp 120−121 °C (DSC, sharp onset; lit . 120−121 °C); [α] 24 D −1.29 ( c 0.85, EtOH), [α] 24 D −2.7 ( c 1.15, CHCl 3 ) {lit .…”

“…120−121 °C); [α] 24 D −1.29 ( c 0.85, EtOH), [α] 24 D −2.7 ( c 1.15, CHCl 3 ) {lit . [α] 20 D +4.4; ( c 0.32, EtOH), lit . [α] 20 D −3.79; ( c 1.0, CHCl 3 )}; FTIR (neat, cm −1 ) 3391, 1744, 1689, 1510, 1498, 1341, 1275, 1260, 1209, 1145, 1110, 1041, 1030, 987, 759, 749; 1 H NMR (500 MHz, CDCl 3 ) δ 7.43−7.05 (m, 10H), 5.65 (br d, J = 8.8 Hz, 1H), 5.27 (d, J = 8.8 Hz, 1H), 5.13−5.02 (m, 2H), 4.48 (br s, 1H), 3.80 (s, 3H), 3.13 (d, J = 3.5 Hz, 1H); 13 C NMR (125 MHz, CDCl 3 ) δ 173.2, 155.7, 138.8, 136.3, 128.7, 128.5, 128.2, 128.1, 127.9, 126.7, 73.4, 67.0, 56.5, 53.1; LRMS (ESI) [M + Na] + 352 (100).…”

N-Acetylphenylisoserinates of Lactarius Sesquiterpenoid Alcohols - Cytotoxic, Antiviral, Antiproliferative and Immunotropic Activities in vitro

“…The compounds were obtained in the Institute of Organic Chemistry, (Warsaw, Po-land). For details on their synthesis and purity, see Barycki et al [21]. The compounds were diluted in DMSO (Sigma; Poznan, Poland).…”