Diastereo- and Regioisomeric Bicyclic Thiohydantions from Chiral 1,3-Thiazolidine-2,4-dicarboxylic acids

✍ Scribed by István Miskolczi; András Zékány; Ferenc Rantal; Anthony Linden; Katalin E. Kövér; Zoltán Györgydeák

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: German
• Weight: 601 KB
• Volume: 81
• Category: Article
• ISSN: 0018-019X
• DOI: 10.1002/hlca.19980810324

✦ Synopsis

Bicyclic thiohydantoins were synthesized in a stereoselective manner by reacting (2R)/(2S)-diastereoisomer mixtures of 1.3-thiazolidine-2,4-dicarboxylic acids or their dimethyl diesters with PhNCS. 5S-Dimethyl-1 Jthiazolidine-2,4-dicarboxylic acid with PhNCS led to a cyclization involving the C = O group at the C(2) center of the thiazolidine ring, while the acid's dimethyl diester gave cyclization involving the C=O group at C(4). In contrast. reactions involving unsubstituted 1,3-thiazolidine-2.4-dicarboxylic acid or its dimethyl diester led to thiohydantoins in which the ring closure had taken place only with the COO group at C(4). lndependcntly of the direction of the ring closure, all reactions produce exclusively products with the (R)-configuration at C(2). The configurational assignments were based on 'H-and I3C-NMR studies, and confirmed by X-ray crystallographic analyses.