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Narcissus and Daffodil

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OH<br />

O<br />

MeO<br />

PhCH 2O<br />

CHO<br />

O<br />

PhCH 2O<br />

OH<br />

HO N<br />

OCH 2Ph<br />

NMe<br />

OMe<br />

PhCH 2O<br />

PhCH 2O<br />

Synthesis of galanthamine 307<br />

on hydrolysis produced (±)-26 (98%). (±)-25 on keeping at 25 °C in the presence of<br />

Ph 3 P (14 h) yielded (±)-2 (51%). Thus the total yield of (±)-2 was 43.6%.<br />

Hence, the concept of using metal-substituted substrate-induced o-diphenol oxidation<br />

in galanthamine synthesis was successful. However, the use of toxic, expensive<br />

<strong>and</strong> scarce compounds means that the scheme is unsuitable for large-scale application.<br />

Synthesis of galanthamine <strong>and</strong> N-norgalanthamine<br />

via belladine-derived amide oxidation<br />

OH<br />

Me<br />

N<br />

MeO OCH 2Ph<br />

A significant achievement in the synthesis of 1 was found in the work of Kametani<br />

et al., 1969a,b <strong>and</strong> Kametani, 1972a, shown on Figure 12.4. 5-Benzyloxy-2-bromo-<br />

NMe<br />

OCH 2Ph<br />

7 8 9 10 11<br />

OH<br />

OMe<br />

OH<br />

MeO OCH 2Ph<br />

12 13 14<br />

O<br />

O<br />

HO<br />

HO<br />

OCH 2Ph<br />

Cl<br />

Me<br />

NH<br />

NMe<br />

15 16 6<br />

O<br />

OMe<br />

Figure 12.2 Synthesis of narwedine (2) via N,O-dimethylnorbelladine (6) (Barton <strong>and</strong><br />

Kirby, 1960, 1962).<br />

2

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