Synthesis of vincamine

Synthesis of Vinca alkaloids and related compounds, LIV. Synthesis of (±)‐16‐deethyl‐vincamines, (Deethyl)‐16‐deethyl‐apovincamines, and their 10‐bromo derivatives

“…The residue was treated with MeOH (2 -3 ml) and allowed to stand at room temp. for [6][7][8][9][10][11][12] General Method for the Preparation of' 16-Deethyl-apovincamine (20) and i0-Bromo-16-deethyl-apouincamine (21): The oxime ester 7 or 8 (3.0 mmol) was heated in a mixture of MeOH (20 ml) and concd. H2S04 (8 ml) at 100°C for 2-6 h. The cold reaction mixture was poured into ice-cold water (50 ml), basified with concd.…”

Recent progress in the chemistry of indole alkaloids and mould metabolites

“…Reduction of (1 25) gave, as major product, 3-epi-alloyohimbine (1 27), but this could not be efficiently epimerized to 3-epi-a-yohimbine (1 26), since (1 27) predominated in the equilibrium mixture. Accordingly, 3-epi-alloyohimbine was epimerized at C-3 by the lead tetra-acetate-sodium borohydride dehydrogenation-reduction sequence to give alloyohimbine (128), which was then epimerized at C-16 to give the C-16 equatorial ester, ayohimbine (129). The final stage was again inversion at C-3, which afforded ( +)-3-epi-a-yohimbine [isorauhimbine (126)] in 2 1 % yield (Scheme 18).…”

Asymmetric Total Synthesis of (+)-21-epi-Eburnamonine Via a Photocatalytic Radical Cascade Reaction

“…1, 1), (−)-eburnamonine (2) and their cis D/E ring fusion congeners ( Fig. 1, 3-5) exhibit significant cerebral/peripheral vasorelaxation and antihypertensive bioactivities, especially 1 and 2 have been used in the treatment of hypertension [9][10][11][12], making them among the most-studied synthetic targets in eburanamine-vincamine family (For selected examples of racemic total synthesis of 1, see: [13][14][15][16][17][18][19][20]; For selected examples of asymmetric total synthesis of 1, see: [21][22][23][24][25][26][27][28][29][30][31][32]; For selected examples of racemic total synthesis of 2, see: ; For selected examples of asymmetric total synthesis of 2, see: [54][55][56][57][58][59][60][61][62]). Quite a few synthetic non-natural analogues also exert bioactivities; for instance, (−)-20-epi-vincamine (6) and (−)-20-epi-eburnamonine (7) with trans D/E ring fusion show better peripheral vasodilation than (+)-vincamine (1) and (−)-eburnamonine (2) [63], and (−)-21-epi-vincamine (8) displays higher binding affinity to human serum albumin than 2 [63].…”

“…Quite a few synthetic non-natural analogues also exert bioactivities; for instance, (−)-20-epi-vincamine (6) and (−)-20-epi-eburnamonine (7) with trans D/E ring fusion show better peripheral vasodilation than (+)-vincamine (1) and (−)-eburnamonine (2) [63], and (−)-21-epi-vincamine (8) displays higher binding affinity to human serum albumin than 2 [63]. However, compared to the cis series (For selected examples of asymmetric total synthesis of 1, see: [21][22][23][24][25][26][27][28][29][30][31][32]; For selected examples of Dedicated to the memory of Professor Jun Zhou.…”