1334401-48-7Relevant academic research and scientific papers
Synthesis of benzothiophene derivatives by Pd-catalyzed or radical-promoted heterocyclodehydration of 1-(2-Mercaptophenyl)-2-yn-1-ols
Gabriele, Bartolo,Mancuso, Raffaella,Lupinacci, Elvira,Veltri, Lucia,Salerno, Giuseppe,Carfagna, Carla
, p. 8277 - 8286 (2011/12/04)
Novel and convenient approaches to benzothiophene derivatives 3 and 5 have been developed, based on heterocyclization reactions of 1-(2-mercaptophenyl)-2- yn-1-ols 2 or 4, respectively, readily available from alkynylation of 2-mercaptobenzaldehydes or 1-(2-mercaptophenyl) ketones 1. In particular, 1-(2-mercaptophenyl)-2-yn-1-ols 2, bearing a CH2R substituent on the triple bond (R = alkyl, aryl), were conveniently converted in fair to good yields (55-82%) into (E)-2-(1-alkenyl)benzothiophenes 3 when allowed to react in the presence of catalytic amounts (2 mol %) of PdI2 in conjunction with KI (KI:PdI2 molar ratio =10) at 80-100 °C in MeCN as the solvent, through a heterocyclodehydration process. On the other hand, 2-alkoxymethylbenzothiophenes 5 were selectively obtained in fair to excellent yields (49-98%) via a radical-promoted substitutive heterocyclodehydration process, by reacting 1-(2-mercaptophenyl)-2-yn-1-ols 4 (bearing an alkyl or aryl substituent on the triple bond) in alcoholic media at 80-100 °C in the presence of a radical initiator, such as AIBN.
