Ethynylation of 2-(furan-2-yl)- and 2-(thiophen-2-yl)pyrroles with acylbromoacetylenes in the Al2O3 medium: relative reactivity of heterocycles

Add time:07/13/2019    Source:sciencedirect.com

2-(Furan-2-yl)- and 2-(thiophen-2-yl)pyrroles are readily ethynylated with acylbromoacetylenes in the solid Al2O3 medium (no solvent, room temperature, 1 h) to afford 5-(furan-2-yl)- and 5-(thiophen-2-yl)-2-acylethynylpyrroles in 39–74% yields. In the case of 2-(furan-2-yl)pyrroles, an alternative ethynylation of the furan ring takes place, the ratio of the furan and pyrrole ring ethynylation products being 1:5–7. No ethynylation of the thiophene ring as well as ethynylation of both heterocycles in a one molecule has been detected. Thus the reactivity of the heterocycles towards the ethynylation system (acylbromoacetylenes/Al2O3) falls in the order: pyrrole>furan>thiophene.

We also recommend Trading Suppliers and Manufacturers of 2-{[2-(furan-2-yl)-4-oxo-4H-chromen-6-yl]oxy}acetamide (cas 6896-10-2). Pls Click Website Link as below: cas 6896-10-2 suppliers

Prev:4-(Furan-2-yl)phenyl-containing polydithienylpyrroles as promising electrodes for high contrast and coloration efficiency electrochromic devices
Next:One-pot synthesis of 3-(furan-2-yl)-4-hydroxy-2H-chromen-2-ones using K10 montmorillonite clay as heterogeneous catalyst)