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Diastereo‐ and Regioisomeric Bicyclic Thiohydantions from Chiral 1,3‐Thiazolidine‐2,4‐dicarboxylic acids
Author(s) -
Miskolczi István,
Zékány András,
Rantal Ferenc,
Linden Anthony,
Kövér Katalin E.,
Györgydeák Zoltán
Publication year - 1998
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.19980810324
Subject(s) - chemistry , thiazolidine , bicyclic molecule , dicarboxylic acid , ring (chemistry) , diastereomer , stereochemistry , stereoselectivity , organic chemistry , catalysis
Bicyclic thiohydantoins were synthesized in a stereoselective manner by reacting (2 R )/(2 S )‐diastereoisomer mixtures of 1,3‐thiazolidine‐2,4‐dicarboxylic acids or their dimethyl diesters with PhNCS. 5,5‐Dimethyl‐1,3‐thiazolidine‐2,4‐dicarboxylic acid with PhNCS led to a cyclization involving the CO group at the C(2) center of the thiazolidine ring, while the acid's dimethyl diester gave cyclization involving the CO 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). Independently 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 1 H‐ and 13 C‐NMR studies, and confirmed by X‐ray crystallographic analyses.