(1) The Friedel¨CCrafts acylation of tert-butylbenzene (5) with 3-chloropropionyl chloride (1) followed by cyclization provid- ed indanone 6, which was further transformed into urea derivative 7, a potent TRPV1 antagonist.
(2) A novel high-yielding one-pot microwave-assisted synthesis of condensed 5-substituted pyranoisoquinoline-1,6-diones 9 from 2-substituted isoquinoline-1,3-diones 8 and 3-chloropropionyl chloride (1) was reported.
(3) Acylation of 2-aminophenol (12) with 3-chloropropionyl chloride (1), followed by cyclization in the presence of polyphosphoric acid (PPA), gave benzoxazole 13, which was further reacted with 4-chlorophenyl-1-piperazine to yield the target benzo[d]oxazole analogue 14, a selective dopamine D4 receptor ligand.