Process for the preparation of 5-carboxyphthalide

  • US 6,703,516 B2
  • Filed: 08/23/2002
  • Issued: 03/09/2004
  • Est. Priority Date: 01/18/2000
  • Status: Expired due to Fees
First Claim
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1. A process for producing citalopram comprising a process for producing 5-carboxyphthalide which comprises adding 1,3,5-trioxane and terephthalic acid to fuming sulfuric acid having an SO3 content of at least 20% and heating the mixture to a temperature of 120 to 145°

  • C.

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