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Iodine‐Catalyzed Synthesis of Chalcogenophenes by the Reaction of 1,3‐Dienyl Bromides and Potassium Selenocyanate/Potassium Sulfide (KSeCN/K 2 S)
Author(s) -
Maity Pintu,
Ranu Brindaban C.
Publication year - 2017
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.201701232
Subject(s) - chemistry , reagent , thiophene , sulfide , iodine , aryl , potassium , catalysis , sodium sulfide , yield (engineering) , combinatorial chemistry , organic chemistry , alkyl , materials science , metallurgy
Abstract The methods available for the synthesis of chalcogenophenes, in general, are associated with drawbacks of harsh conditions, use of costly metals, broad applicability, tedious purification process and low yield. To avoid these drawbacks a transition metal‐free iodine‐catalyzed reaction of aryl‐susbstituted 1,3‐dienyl bromides with potassium selenocyanate/potassium sulfide (KSeCN/K 2 S) leading to the corresponding selenophenes and thiophenes has been developed. Iodine is relatively benign, less expensive and readily available. Several diversely substituted selenophenes and thiophenes have been obtained by this procedure in high yields. Using this procedure 2‐(4‐chlorophenyl)thiophene, a key intermediate for the synthesis of a melanin concentrating hormone receptor ligand involved in the treatment of eating disorders, weight gain, obesity, depression and anxiety has been synthesized. Although the reaction is one‐pot essentially it proceeds in two steps involving a selenocyanate/thiolate intermediate leading to the selenophene/thiophene. The simple operation, use of inexpensive reagents and a metal‐free process make this procedure more attractive for an easy access to substituted selenophenes and thiophenes.