1987 Fiscal Year Final Research Report Summary
Syntheses of Ankorine Congeners in Different Oxidation States.
| Project/Area Number |
61570997
|
|---|
| Research Category |
Grant-in-Aid for General Scientific Research (C)
|
| Allocation Type | Single-year Grants |
|---|
| Research Field |
Chemical pharmacy
|
|---|
| Research Institution | Kanazawa University |
|---|
Principal Investigator |
FUJII Tozo Professor, Faculty of Pharmaceutical Sciences, Kanazawa University, 薬学部, 教授 (20019649)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
OHBA Masashi Assistant, Faculty of Pharmaceutical Sciences, Kanazawa University, 薬学部, 助手 (60115219)
|
|---|
| Project Period (FY) |
1986 – 1987
|
| Keywords | Alangium alkaloid / Benzo[a]quinolizidine alkaloid / Mercuric acetate oxidation / Ruthenium tetroxide oxidation / Debenzylation / Cis-trans thermal isomerization / キナ塩基の化学変換 |
|---|
| Research Abstract |
A series of congeners (I-IV) of the Alangium alkaloid ankorine (I), differing in oxidation state at the side chain, were synthesized through the "cincholoipon-incorporating route" as shown below.
1. The starting material selected for these syntheses was cincholoipon ethyl ester [(+)-V], and it was prepared from commercially available cinchonine in 50% overall yield according to the classical 7-step degradation procedure.
2. The ester (+)-V was then converted into the tricyclic amino ester (-)-VI, the key intermediate in the previous chiral synthesis of I, through the previously reported 10-step route.
3. The tricycle (-)-VI was converted into the target alancine (II) by alkaline hydrolysis and subsequent hydrogenolysis. Conversion of (-)-VI into 8-hydroxyprotoemetine (III), another target, was efeected by hydrogenolysis and subsequent i-Bu_2AlH reduction. Wolff-Kishner reduction of III gave the 3-ethyl congener IV, yet another target, in good yield.
4. An alternative synthetic route to I-IV was established by application of the "RuO_4 oxidation method".
5. To our surprise, the previously reported spectral data of "natural alancine" did not match those of the synthetic II,but matched those of its hydrochloride salt instead. It thus became evident that the physical, chemical, and spectral data reported by Schiff et al. for "natural alancine" were in reality those for II・HCl. With the completion of the above syntheses and characterization of II-IV, the search for these substances in the plant source may proceed.
|
Research Products
(8 results)
