A new entry to phenanthridine ring systems via sequential application of Suzuki and the modified Pictet–Spengler reactions

Abstract

A mild, efficient and versatile method has been developed for the two step synthesis of phenanthridine ring systems using the Suzuki and the modified Pictet-Spengler strategy. The strategy involves synthesis of a substrate in which an aryl amine is tethered to an activated arene ring at the carbon ortho to the activated carbon nucleophile so as to facilitate the formation of phenanthridine ring via pi-cyclization.

Catalytic Asymmetric Pictet–Spengler-Type Reaction for the Synthesis of Optically Active Indolo[3,4-cd][1]benzazepines

“…(1) Preparation of 2-Bromoaniline Derivatives 2-Bromo-4-methoxyaniline, 3 2-bromo-4-trifluoromethoxyaniline, 4 2-bromo-4,6-dimethylaniline, 5 and 2-bromo-1-naphthylamine 6 were prepared according to literature procedures. Shown below is the procedure for the preparation of 2-bromo-4-phenoxyaniline.…”

N-(4,4′-Dibromo-[1,1′-biphenyl]-2-yl)benzamide

“…For applications of the title compound, see: Libman & Slack (1951); Mandadapu et al (2009); Youn & Bihn (2009); Yulan et al (2010). For pharmacological properties of biphenyl aniline, see: Zhu et al (2008).…”

A new synthetic approach to 6-unsubstituted phenanthridine and phenanthridine-like compounds under mild and metal-free conditions

“…The construction of such systems can be accomplished via two known methods, which include the photo-irradiation of the iminylbiaryl compounds and the modified Pictet-Spengler reaction involving the methyleneiminium ion formation from biarylaniline and formaldehyde and cyclization under refluxing toluene. 9 In this regard, the formation of such iminium ions can be difficult and provided the desired product in moderate yields, possibly due to the use of formaldehyde. We envision that the generation of the methyleneiminium ion could be more efficient starting from arylmethyl azide.…”