Efficient synthesis of isoindolones by intramolecular cyclisation of pyridinylbenzoic acids

Abstract

A straightforward one-pot method for the synthesis of unreported pyrido-[2,1-a]isoindolones in excellent yield is described. Two novel isoindolones were synthesized and fully characterized. The alkyl substituents on the pyridine play...

A Rapid, Highly Sensitive and Selective Phosgene Sensor Based on 5,6‐Pinenepyridine

“…The sensor 2 was easily synthetized as previously reported by our group, [33] starting from the brominated derivative 1 , [34] which underwent lithiation and carboxylation with gaseous CO 2 , as shown in Scheme 2 . The sensing reaction involves the activation of the carboxylic acid by phosgene in the presence of triethylamine (TEA).…”

“…We hypothesize that the reaction involves the formation of an acyl chloride intermediate (not isolated), which undergoes a fast nucleophilic attack from the pyridinic N, followed by deprotonation of the pinene unit, similarly to the mechanism elucidated in our recent work. [33] …”

“…Synthesis of 2 : Compound 2 was synthesised as previously reported [33] . A solution of 1 (4.07 6, 12.4 mmol, 1 equiv.)…”

“…Synthesis of 2 : Compound 2 was synthesised as previously reported. [33] A solution of 1 (4.07 6, 12.4 mmol, 1 equiv.) in anhydrous THF (40 mL) was treated under inert atmosphere, at −78 °C, with 1 equiv.…”

“…We hypothesize that the reaction involves the formation of an acyl chloride intermediate (not isolated), which undergoes a fast nucleophilic attack from the pyridinic N, followed by deprotonation of the pinene unit, similarly to the mechanism elucidated in our recent work. [33] The photophysical properties of the sensor 2 (Figure S1) and its corresponding isoindolone-type product 3 make this sensing reaction an efficient and promising candidate for the detection of phosgene in solution and in gas state. The absorption of 2 shows a λ max = 294 nm, with no emission band when excited at 474 nm.…”