Bioinspired Gram-Scale Synthesis of Alstoscholarinoid B

Abstract

Herein, we describe a gram-scale synthesis of alstoscholarinoid B, a rearranged triterpenoid with potent antihyperuricemic bioactivity. This synthesis was inspired by the biogenetic hypothesis and achieved in seven steps from oleanolic acid with an overall yield of 51%.

Gram-scale synthesis of alstoscholarinoid B via a bio-inspired strategy

“…2). 4 The key precursor 5 could in turn be accessed via the oxidative cleavage of the Δ 11,12 -double bond and removal of the acetyl protection of hexacyclic triterpene 6. To this end, we posited that sequential reduction of ketone 7 followed by regioselective elimination could establish the Δ 11,12 -double bond of 6.…”

“…[α] D 25:0 = −28.9 (c 0.1, CHCl 3 ); 1 H NMR (600 MHz, CDCl 3 ) δ 10.02 (d, J = 4.5 Hz, 1H), 9.95 (d,J = 4.8 Hz,1H),2H),3H),5.31 (d,J = 12.4 Hz,1H),5.17 (d,J = 12.6 Hz,1H),3.19 (dd,J = 11.6,4.7 Hz, 1H), 2.82-2.76 (m, 1H), 2.61 (s, 1H), 2.04 (s, 1H), 1.94-1.86 (m, 2H), 1.78-1.46 (m, 12H), 1.36-1.26 (m, 8H), 1.22 (s, 3H), 1.18 (s, 3H), 1.13 (s, 3H), 0.90 (s, 3H), 0.83 (s, 3H), 0.75 (s, 3H). 13 C NMR (151 MHz, CDCl 3 ) δ 208.…”

“…3a Despite their interesting biological activity, the low abundance of alstoscholarinoids hampered further biological investigations, which called for a scalable synthesis method. 4…”