Short Synthesis of Methylphenidate and Itsp-Methoxy Derivative
摘要:
A short method for the preparation of racemic threo- and erythro-methylphenidate derivatives is described. Condensation between a-ethoxy carbamate 1 and silyl ketene acetals 2a-b in the presence of TESOTf (20 mol%) afforded a 1.5:1 mixture of carbamates 3a-b/4a-b. Hydrogenolysis in EtOH followed by treatment with 3N HCl/MeOH afforded the corresponding hydrochlorides 7a-b/8a-b in good yields.
Uncatalyzed Reaction of Silyl Ketene Acetals with Oxalyl Chloride: A Straightforward Preparation of Symmetrical Pulvinic Acids
作者:Benoît Heurtaux、Claude Lion、Thierry Le Gall、Charles Mioskowski
DOI:10.1021/jo048403v
日期:2005.2.1
natural pulvinicacids were synthesized. Silyl ketene acetals derived from methyl arylacetates (4 equiv) reacted with oxalyl chloride at −78 °C, without the need of adding a catalyst. After treatment of the crude diketones with DBU and acidification with hydrochloric acid, symmetrical pulvinicacids methyl esters were obtained. Saponification of the methyl esters afforded the corresponding pulvinic acids