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The Use of Switchable Polarity Solvents for the Synthesis of 16‐Arylidene Steroids via Claisen–Schmidt Condensation
Author(s) -
Ispán Dávid,
SzántiPintér Eszter,
Papp Máté,
Wouters Johan,
Tumanov Nikolay,
Zsirka Balázs,
Gömöry Ágnes,
Kollár László,
SkodaFöldes Rita
Publication year - 2018
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.201800356
Subject(s) - chemistry , ethylene glycol , ionic liquid , condensation , catalysis , claisen condensation , solvent polarity , ionic bonding , condensation reaction , solvent , base (topology) , organic chemistry , ion , physics , thermodynamics , mathematical analysis , mathematics
Switchable polarity recyclable solvent mixtures were applied as reaction medium and catalyst to replace the conventional base catalysts in the Claisen–Schmidt condensation of 17‐oxo steroids with aromatic aldehydes. Reversibility between ionic and nonionic forms of the new 2‐ n ‐butyl‐1,1,3,3‐tetramethylguanidine ( n Bu‐TMG)/ethylene glycol/CO 2 and 2‐ tert ‐butyl‐1,1,3,3‐tetramethylguanidine ( t Bu‐TMG)/ethylene glycol/CO 2 systems were proved by conductivity measurements. The structure of the ionic form was established by 1 H NMR and IR measurements and by quantum chemical calculations. The steroidal products with androstane and estrane skeleton were characterised with spectroscopic methods (NMR, IR, MS).