Utilization of N-acyl compounds for the synthesis of tricyclic and bridged heterocyclic compounds.

Abstract

N-acyl derivative 4 was prepared via the reaction of methyl anthranilate with ethyl bromoacetate then refluxing the formed amino ester 3 with acetic anhydride. Cyclization of 4 in presences of sodium methoxide and methanol forming 2,4-pyrrolidindione derivative 5. 2,4-Quinolidinone 6 was obtained via cyclization of 4 in dry toluene and sodium hydride. On the other hand, indolinone derivative 8 was obtained by cyclization of 4 in toluene and free from alcohol due to retro Diekmann-condensation. On treatment of 8 with sodium hydride, refluxing toluene and in presences of Crown ether gave tricyclic compound 9. Also, treatment of 2-pyrrolidinone with trimethylene chlorobromide produced 10 which cyclized using base and solvent to the bridged ring derivatives 11. The acidic hydrolysis of 11 afforded the corresponding amino acid 13. Whereas derivative 14 was obtained by the reaction of 2-pyrrolidinone with ethyl 3-bromopropionate which on cyclization gave azabicyclo[3,2,1]octan-4,8-dione derivative 15. Compound 15 underwent acidic hydrolysis to the amino ketone derivative azepanone hydrochloride 17.