**BICYCLO (3.3.0) OCTANE DERIVATIVE**

NEW MATERIAL:A bicyclo [3.3.0] octane derivative expressed by formula I [A is oxo or OH which may be protected; B is protected carboxy, hydroxymethyl, formyl or formula II (R1 is alkyl or alkenyl; D is oxo or OH); Z is a protecting group of the carbonyl group]. EXAPMLE:4β-Methoxycarbonyl-7,7'-ethylenedioxybicyclo[3.3.0]octane-3-one.

USE: A synthetic intermediate for novel prostacycline drivatives, expressed by formula IV(R2 is H or alkyl; n is 18), and having the inhibitory action on the blood platelet agglutination.

PROCESS: A compound expressed by formula III is subjected to the Dieckmann reaction to give a compound expressed by formula I a, which is then reduced to afford a compound expressed by formula I b. The hydroxyl group in the resultant compound expressed by formula I b is subsequently protected to give a compound expressed by formula I c, which is then reduced to afford a compound expressed by formula pound expressed by formula I d. The resultant a compound expressed by formula I e, which is then reacted with a Wittig reagent to give a compound expressed by formula I f. The compound expressed by formula If is further reduced to give the aimed compound expressed by formula I g.

SAKAI KIYOSHI

KOBAYASHI SHINSAKU

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**C07D309/12***;*

**A61K31/557***;*

**A61P43/00***;*

**C07C41/00***;*

**C07C43/305***;*

**C07C43/315***;*

**C07C45/00***;*

**C07C47/37***;*

**C07C47/47***;*

**C07C49/385***;*

**C07C49/587***;*

**C07C49/733***;*

**C07C51/00***;*

**C07C59/46***;*

**C07C62/38***;*

**C07C67/00***;*

**C07C69/608***;*

**C07C69/732***;*

**C07C69/757***;*

**C07D317/72***;*

**C07D407/12***; (IPC1-7): A61K31/557; C07C43/315; C07C47/37; C07C47/47; C07C49/385; C07C49/587; C07C49/733; C07C59/46; C07C62/38; C07C69/608; C07C69/732; C07C69/757; C07D309/12; C07D317/72; C07D407/12; C07F7/18*

**C07F7/18**