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US 6,642,424 B2Granted
Intermediates and improved processes for the preparation of neplanocin A
AssigneeChisso Corporation
InventorsNaoyuki Yoshida, Kunio Ogasawara
Life of this patent
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Abstract
Intermediate compounds, including 2-(t-butyldimethylsilyloxymethyl)-3,4-[(dimethylmethylene)dioxy]-5-hydroxy-tricyclo[5.2.1.02,6]dec-8-ene, which are useful for the synthesis of neplanocin A having strong antitumor activity. Improved processes for the preparation of neplanocin A, starting from optically active 2-hydroxymethyl-5-hydroxy-tricyclo[5.2.1.02,6]deca-3,8-diene and via a key step comprising a retro-Diels-Alder reaction of the above intermediate.
Claims2
A compound of formula (1)
- wherein R1 and R2 are independently hydrogen or an alkanoyl group of 2-20 carbons.
A process for the preparation of neplanocin A which comprises the steps of:
- (a) reacting a compound of formula (1′)
- with a halogenating agent, to form a compound of formula (2)
- wherein X is halogen;
- (b) reacting the compound (2) with an agent for the protection of hydroxyl groups, to form a compound of formula (3)
- wherein X is as defined above and Y is a protecting group;
- (c) treating the compound (3) with an oxidizing agent, to form a compound of formula (4)
- wherein X and Y are as defined above;
- (d) reacting the compound (4) with a ketalizing agent, to form a compound of formula (5)
- wherein X and Y are as defined above;
- (e) treating the compound (5) with a dehalogenating agent, to form a compound of formula (6)
- wherein Y is as defined above;
- (f) subjecting the compound (6) to a retro-Diels-Alder reaction, to form a compound of formula (7)
- wherein Y is as defined above;
- (g) treating the compound (7) with an oxidizing agent, to form a compound of formula (8)
- wherein Y is as defined above;
- (h) reducing the compound (8) with a reducing agent, to form a compound of formula (9)
- wherein Y is as defined above;
- (i) subjecting the compound (9) to a Mitsunobu reaction, to form a compound of formula (10)
- wherein Y is as defined above, followed by deprotection.
16 more elements
Dependencies are inferred from the claim text.