Cesar A Colon

US Patent:

20020049350, Apr 25, 2002

Filed:

Jun 26, 2001

Appl. No.:

09/891601

Inventors:

Xiaoyong Fu - Edison NJ, US
Jianguo Yin - Edison NJ, US
Timothy McAllister - Westfield NJ, US
Cesar Colon - Rio Piedras PR, US

International Classification:

C07C069/73

US Classification:

560/060000, 560/183000

Abstract:

A single batch process for preparing (R)-benzyl-4-hydroxy-2-pentynoate by reacting (R)-3-butyn-2-ol with 1,1,1,3,3,3-hexamethyldisilazane to silylate the starting alcohol, followed by deprotonation with an alkyl lithium compound, then a reaction with a haloformate compound, and finally a hydrolysis reaction to arrive at the product ester.

US Patent:

60938129, Jul 25, 2000

Filed:

Jan 7, 1994

Appl. No.:

8/179008

Inventors:

Junning Lee - Springfield NJ
Timothy McAllister - Fords NJ
Cesar Colon - Rahway NJ
Derek H. R. Barton - College Station TX
Ronald Breslow - Englewood NJ
Anantha Sudhakar - East Brunswick NJ

Assignee:

Schering Corporation - Kenilworth NJ

International Classification:

C07D20508

US Classification:

540200

Abstract:

This invention provides an improved process for producing azetidinones. More particularly, this invention provides the steps of producing an trans-azetidinone represented by the formula ##STR1## from a carboxylic acid R. sup. 2 --D--CH. sub. 2 COOH, an aldehyde R. sup. 1 --A--CHO and an amine RNH. sub. 2, by the steps of: (a1) converting a carboxylic acid to the corresponding acid chloride; (b1) deprotonating a chiral oxazolidinone and treating the resulting anion with the product of step (a1); (c1) enolizing the product of step (b1) and condensing with the aldehyde; (d1) hydrolyzing the product of step (c1); (e1) condensing the product of step (d1) with the amine; and (f1) cyclizing the product of step (e1). Alternatively, the process comprises (a2) enolizing the product of step (b1) and condensing, in the presence of a Lewis acid, with a Schiff's base prepared from the aldehyde and the amine; and (b2) cyclizing the product of step (a2).