Synthesis of taxol enhancers
View Patent ↗Disclosed is a method of preparing a thiohydrazide product compound from a hydrazide starting compound. The hydrazide starting compound is represented by Structural Formula (I): The thiohydrazide product compound is represented by Structural Formula (II): In Structural Formulas (I)-(II), R 1 and R 2 are independently an aliphatic group, a substituted aliphatic group, an aryl group or a substituted aryl group, or R 1 and R 2 taken together with the carbon and nitrogen atoms to which they are bonded, form a non-aromatic heterocyclic ring optionally fused to an aromatic ring. When R 2 is an aryl group or a substituted aryl group, then R 5 is a hydrazine protecting group; and when R 2 is an aliphatic or substituted aliphatic group, then R 5 is —H or a hydrazine protecting group. R 10 is —H or a substituted or unsubstituted alkyl group. The method comprising the step of reacting the starting compound with a thionylating reagent.
1. A method of preparing a compound represented by the following structural formula:
said method comprising the step of reacting Z-C(O)—CH 2 —C(O)-Z or HO—C(O)—CH 2 —(CO)—OH and a carboxylic acid activating agent with a thiohydrazide compound represented by the following structural formula:
wherein each Z is a leaving group.
2. The method of claim 1 , wherein the method comprises the step of reacting Z-C(O)—CH 2 —C(O)-Z with the thiohydrazide compound, and both Zs are —Cl or —OR, wherein R is phenyl or phenyl substituted with an electron-withdrawing group.
3. The method of claim 1 , wherein the method comprises the step of reacting HO—C(O)—CH 2 —C(O)—OH and a carboxylic acid activating agent with the thiohydrazide compound.
4. The method of claim 3 , wherein the carboxylic acid activating agent is selected from the group consisting of 1,1′-carbonyldiimidazole (CDI), isobutyl chloroformate, dimethylaminopropylethyl-carbodiimide (EDC), and dicyclohexyl carbodiimide (DCC).
5. The method of claim 4 , wherein the carboxylic acid activating agent is dicyclohexyl carbodiimide (DCC).
6. The method of claim 1 , wherein the thiohydrazide compound is prepared by reacting a compound represented by the following structural formula:
with a thionylating agent.
7. The method of claim 6 , wherein the thionylating agent is selected from the group consisting of Lawesson's Reagent, phosphorus pentasulfide, Scheeren's Reagent (P 4 S 10 -Na 2 S), P 4 S 10 -N(ethyl) 3 , Davy's Reagent and Heimgarner's reagent.
8. The method of claim 7 , wherein the thionylating agent is Lawesson's Reagent.