A. Haight, A. E. Bailey, W. S. Baker
Oct 16, 2004
Citations
1
Influential Citations
38
Citations
Journal
Organic Process Research & Development
Abstract
Fiduxosin (1) has been under development at Abbott Laboratories for the treatment of benign prostatic hyperplasia. A convergent strategy required methodologies for preparation of an enantiomerically pure 3,4-cis-disubstituted pyrrolidine and a 2,3,5-trisubstituted thienopyrazine in a regiospecific manner. A [3+2] cycloaddition of an enantiopure azomethine ylide followed by a diastereoselective crystallization was employed to prepare the benzopyranopyrrolidine in high diastereomeric and enantiomeric purity. Conditions for reduction of an O-aryl lactone susceptible to epimerization were developed, and cyclization of the alcohol/phenol to the ether was accomplished in high yield. The thienopyrazine was prepared by condensation of methyl thioglycolate and a regiospecifically prepared 2-bromo-3-cyano-5-phenylpyrazine. Conditions for effective halogen substitutive deamination to prepare regiospecific trisubstituted pyrazines will be described.