Synthesis of Pyrido[1,2-a]indole Malonates and Amines through Aryne Annulation

Abstract

Pyrido[1,2-a]indoles are known as medicinally and pharmaceutically important compounds, but there is a lack of efficient methods for their synthesis. We report a convenient and efficient route to these privileged structures starting from easily accessible 2-substituted pyridines and aryne precursors. A small library of compounds has been synthesized utilizing the developed method, affording variously substituted pyrido[1,2-a]indoles in moderate to good yields.

Copper(II) Schiff base complexes and their mixed thin layers with ZnO nanoparticles

“…Powder X-ray diffraction (PXD) analysis was performed using a Philips (Almelo, The Netherlands) XPERT θ-2θ diffractometer with CuKα radiation. The indentation properties of the layers were made on NHT2 microindentation tester (TTX-NHT) from Anton Paar TriTec SA with a Berkovich indenter using loads 20 and 100 mN and holding time of 5 s. The system hardness and elastic modulus were determined from the indentation curves by the standard Oliver [35][36][37][38][39][40] (vs, very strong; s, strong; m, medium; w, weak, vw ver weak) (figure 1).…”

Intermolecular C–O addition of carboxylic acids to arynes: synthesis of o-hydroxyaryl ketones, xanthones, 4-chromanones, and flavones

“…The poor yield in this reaction can be attributed to the high reactivity of the nucleophilic pyridine nitrogen toward benzyne, an often reported process in the literature. 27 The reaction of the electron-poor nitro-substituted carboxylic acid under our optimized reaction conditions provided the desired xanthone 24 in only a 48% yield, with complications during isolation of the desired product. However, running this reaction under reaction conditions reported by the Greaney group for a related insertion into the C-N bond of aromatic amides 2 afforded the xanthone 24 in a high 87% yield (entry 4).…”

Synthesis ofo-(Dimethylamino)aryl Ketones, Acridones, Acridinium Salts, and 1H-Indazoles by the Reaction of Hydrazones and Arynes

“…Despite the well-documented reactivity of pyridines with arynes, 7,25 a number of substituted pyridines provided the expected aminoaryl ketones in high yields. Thus, hydrazones derived from nicotinaldehyde ( 63 ), 2-methoxynicotinaldehyde ( 65 ), and picolinaldehyde ( 67 ) provided the corresponding products in 55%, 78%, and 82% yields respectively (entries 28-30).…”