Stereochemie der Rhodanine (II.)

Abstract

1) B. 50, 90 [1917]. ' ) Bezfiglich der Ursache hierzu siehe B. H o l m b e r g , 1. r,

4-Thiazolidinones.

“…If the asymmetric carbon atom is not involved in the keto-enol tautomerism, optically active cyclized products can be obtained. The use of active amines in the synthesis of rhodanine derivatives (313,347) and of thioureas derived from active amines in the synthesis of 2-imino-4-thiazolidinones (393) gives active cyclized products. Racemic 2-(5-carboxypentyl) -4-thiazolidinone is resolved by means of its brucine salts (429).…”

“…Likewise, an optically inactive 3-amino-5-carboxymethylrhodanine is obtained from ammonium dithiocarbazinate and sodium Z-bromosuccinate (526). When both hydrogen atoms on the methylene carbon are replaced by alkyl or substituted alkyl groups, and such tautomerism is not possible, optically active rhodanine derivatives are formed from the corresponding optically active -haloalkanoic acids, while inactive rhodanine derivatives are obtained from the racemic acids (347).…”