Resin-​bound 1,​5,​7-​triazabicyclo[4.4.0]​dec-​5-​enes were prepd. by copolymn. of 1,​4-​divinylbenzene and 4-​vinylbenzyl chloride in the presence of either 2-​ethylhexanoic acid, 1-​chlorobutane, or cyclohexanol as a porogen followed by reaction with 1,​5,​7-​triazabicyclo[4.4.0]​dec-​5-​ene (TBD)​; the products were compared by IR and SEM, and their surface areas and pore sizes were detd. The resin-​bound TBD were used as supported catalysts for the Michael addns. of 4-​hydroxycoumarin to benzylideneacetones (E)​-​MeCOCH:CHR (R = Ph, 4-​O2NC6H4, 4-​ClC6H4, 4-​MeOC6H4) in cyclopentyl Me ether to yield the (aryloxobutyl)​hydroxycoumarins warfarin and three of its analogs I (R = Ph, 4-​O2NC6H4, 4-​ClC6H4, 4-​MeOC6H4) in 82-​100​% conversions over 72-​96 h; the catalysts were recovered by filtration and reused twice without loss of activity.

Synthesis and characterization of novel polystyrene-supported TBD catalysts and their use in the Michael addition for the synthesis of Warfarin and its analogues

ALONZI, MATTEO;BROGGI, Alessandra;LANARI, DANIELA;MARROCCHI, Assunta;VACCARO, Luigi
2014

Abstract

Resin-​bound 1,​5,​7-​triazabicyclo[4.4.0]​dec-​5-​enes were prepd. by copolymn. of 1,​4-​divinylbenzene and 4-​vinylbenzyl chloride in the presence of either 2-​ethylhexanoic acid, 1-​chlorobutane, or cyclohexanol as a porogen followed by reaction with 1,​5,​7-​triazabicyclo[4.4.0]​dec-​5-​ene (TBD)​; the products were compared by IR and SEM, and their surface areas and pore sizes were detd. The resin-​bound TBD were used as supported catalysts for the Michael addns. of 4-​hydroxycoumarin to benzylideneacetones (E)​-​MeCOCH:CHR (R = Ph, 4-​O2NC6H4, 4-​ClC6H4, 4-​MeOC6H4) in cyclopentyl Me ether to yield the (aryloxobutyl)​hydroxycoumarins warfarin and three of its analogs I (R = Ph, 4-​O2NC6H4, 4-​ClC6H4, 4-​MeOC6H4) in 82-​100​% conversions over 72-​96 h; the catalysts were recovered by filtration and reused twice without loss of activity.
2014
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11391/1196080
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