Reactions of cyclic oxalyl compounds, 37. Substituent effects on the site of nucleophilic attack at 1H-pyrrole-2,3-diones
✍ Scribed by Kappe, C. Oliver ;Terpetschnig, Ewald ;Penn, Gerhard ;Kollenz, Gert ;Peters, Karl ;Peters, Eva-Maria ;von Schnering, Hans Georg
- Publisher
- John Wiley and Sons
- Year
- 1995
- Tongue
- English
- Weight
- 740 KB
- Volume
- 1995
- Category
- Article
- ISSN
- 0947-3440
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✦ Synopsis
Abstract
Reactions of 1__H__‐pyrrole‐2,3‐diones 2a‐i with N‐ and O‐nucleophiles proceed by initial attack at C‐2 or/and C‐5. Consequently, earlier results suggesting structures of type A (attack at C‐3) have to be revised (5, 13, 17, 18b). In general, electron‐withdrawing substituents at C‐4 favor attack at C‐5 with formation of 2‐pyrrolones 5, 6, 10, 13, 17, and 20. Alternatively, attack at C‐2 leads to α‐oxobutenoic acid derivatives 3, 7, 11, 12, 15, and 18. IR and ^13^C‐NMR spectroscopic techniques were employed to differentiate between the possible isomeric addition products formed. The structure of methyl α‐oxobutenoate 15 was established by an X‐ray crystallo‐graphic analysis.