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Microwave‐Enhanced Efficient Regioselective Synthesis of 1,3,4‐Trisubstituted 2‐Mercaptoimidazoles on a Soluble Support
Author(s) -
Yellol Gorakh S.,
Chou ChengTing,
Chang WangJin,
Maiti Barnali,
Sun ChungMing
Publication year - 2012
Publication title -
advanced synthesis and catalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.541
H-Index - 155
eISSN - 1615-4169
pISSN - 1615-4150
DOI - 10.1002/adsc.201100640
Subject(s) - regioselectivity , chemistry , thiourea , combinatorial chemistry , polyethylene glycol , condensation reaction , condensation , peg ratio , organic chemistry , catalysis , physics , finance , economics , thermodynamics
A novel efficient synthetic method for regioselective synthesis of optically active 2‐mercaptoimidazoles with three points of structural diversity was investigated on a polyethylene glycol (PEG) support. The key synthetic steps involve (i) synthesis of thiourea derivatives of polymer‐supported amino acids with isothiocyanates and (ii) one‐pot regioselective condensation of PEG‐linked thiourea with α‐bromo ketones to furnish the 2‐mercaptoimidazole skeleton under microwave conditions. An excellent regioselectivity was observed during this one‐pot condensation reaction which was further supported by NOE studies. In addition to three sets of structural diversity, supplementary chirality at the α‐position of the 2‐mercaptoimidazole skeleton is the key feature of this synthesis. A representative set of 2‐mercaptoimidazoles was efficiently assembled on soluble support utilizing various L ‐amino acids, isothiocyanates and α‐bromoaryl ketones with good yields.