| 摘要 |
<p>Neohesperidine dihydrochalkone (C) is obtained from naringine (A) by (a) dissolving (A) in 20% aq. KOH soln.; (b) adding isovanillin to the soln.; (c) refluxing for 5 h., (d) cooling; (e) adjusting to pH 6 with conc. HCl to ppt. neohesperidine (B), which is separated by filtering and vacuum drying, (f) dissolving (B) in 10% aq. KOH soln.; (g) cooling; (h) adding a Pd/C catalyst (D); (i) hydrogenating at 35 deg.C under 3kg/sq.cm. pressure with elimination of oxygen by flushing with N2 in a hydrogenator; (j) discharging and adjusting to pH 5 max. with conc. HCl in the cold; (k) centrifuging to separate (D); (l) filtering the liquid, and (m) crystallising in the cold to ppte. (C).</p> |
