Selective N-alkylation of isoquinolines, benzazepines and thienopyridines with aromatic aldehydes and naphthols. Issue 39 (30th September 2015)

• Record Type: Journal Article
• Authors: Sas, Judit; Szatmári, István; Fülöp, Ferenc
• Is Part Of: Tetrahedron. Volume 71:Issue 39(2015)
• Page Start: 7216
• Page End: 7221
• Publication Date: 2015-09-30
• Subjects: Mannich reaction -- Aminonaphthol -- Tetrahydroisoquinoline -- N-alkylation -- α-Functionalization; Chemistry, Organic -- Periodicals; 547.005
• DOI: 10.1016/j.tet.2015.03.011
• Languages: English
• ISSNs: 0040-4020

Abstract

Abstract: The reactions of 1- or 2-naphthol, benzaldehyde or substituted benzaldehydes with tetrahydroisoquinoline, tetrahydrobenzo[ d ]azepine, tetrahydrobenzo[ c ]azepine or tetrahydrothieno[3, 2- c ]pyridine under solvent-free conditions, allowed a series of tertiary aminonaphthols to be prepared. The reactions were accelerated by the use of microwave irradiation, and the yields were also improved. As an exception, the aminoalkylation of 2-naphthol with 1, 2, 3, 4-tetrahydroisoquinoline in the presence of benzaldehyde led to the parallel N -alkylation and redox α-arylation of the tetrahydroisoquinoline in a ratio of 4:1. The reaction of 1-naphthol with 2, 3, 4, 5-tetrahydro-1 H -benzo[ c ]azepine led to the formation of the N -alkylated compound as a single product, illustrating that the reaction route depends on the structures of the cyclic amine and the naphthol. Graphical abstract: