Temperature Selective Diastereo-Recognition (TSD): Enantiomeric Ibuprofen via Environmentally Benign Selective Crystallization
摘要:
Selective crystallization of ibuprofen/lysinate from 1 mol of (R,S)-(racemic) ibuprofen and less than or equal to0.5 mol of (S)-lysine in aqueous ethanol affords either (S)-(+)-ibuprofen/(S)-lysinate or (R)-ibuprofen/(S)-lysinate (in preponderance) depending on the crystallization conditions. The previously unreported temperature selective diastereo-recognition (TSD) provides simple and efficient means to prepare either enantiomer of ibuprofen from (R,S)-ibuprofen utilizing the same commercially available inexpensive resolving agent, (S)-lysine. The unwanted enantiomeric ibuprofen could be recovered from the mother liquor and racemized by a simple, relatively waste-free thermal process. This racemization method when utilized in conjunction with the selective crystallization technology provides a simple, efficient, and eco-friendly means to prepare (S)-(+)-ibuprofen lysinate in an overall essentially quantitative yield. This technology also incorporates the fundamental principle of atom economy (via direct production of the preferred pharmaceutical salt of (S)-lysine).
Temperature Selective Diastereo-Recognition (TSD): Enantiomeric Ibuprofen via Environmentally Benign Selective Crystallization
摘要:
Selective crystallization of ibuprofen/lysinate from 1 mol of (R,S)-(racemic) ibuprofen and less than or equal to0.5 mol of (S)-lysine in aqueous ethanol affords either (S)-(+)-ibuprofen/(S)-lysinate or (R)-ibuprofen/(S)-lysinate (in preponderance) depending on the crystallization conditions. The previously unreported temperature selective diastereo-recognition (TSD) provides simple and efficient means to prepare either enantiomer of ibuprofen from (R,S)-ibuprofen utilizing the same commercially available inexpensive resolving agent, (S)-lysine. The unwanted enantiomeric ibuprofen could be recovered from the mother liquor and racemized by a simple, relatively waste-free thermal process. This racemization method when utilized in conjunction with the selective crystallization technology provides a simple, efficient, and eco-friendly means to prepare (S)-(+)-ibuprofen lysinate in an overall essentially quantitative yield. This technology also incorporates the fundamental principle of atom economy (via direct production of the preferred pharmaceutical salt of (S)-lysine).
A new, simple and efficient procedure for the preparation of secondary amides through internal condensation of acylmethanesulfonamides ammonium salts is described. The selective acylation of mixed primary–secondary amines could be an attractive application of the new method.