Facile preparation of 3-substituted 2-quinazolinones via electrogenerated base

Abstract

The first 4-alkenylquinazolinone synthesis was described by Brack 17 as an acidic rearrangement reaction starting from quinoline-1-carboxamides. This procedure was applied by Zolotykh. 18 Similarly, Molina et al. 19 described the 4-methylene derivatives formation when refluxing 2-[(aminocarbonyl)

A Facile One‐Pot Synthesis of 1,2,3,4‐Tetrahydroisoquinoline‐1‐carbonitriles via the Electrogenerated Cyanide Anions from Acetonitrile

“…32, which is react very easily to deprotonate and to initiate many base catalyzed reactions . The electroreduction of acetonitrile leads to the synthesis of a large family of heterocycles, such as quinazolinone derivatives, imino‐1,3‐thiazolines, imino‐4‐oxothiazoles , imidazole carboxylates or triazinane‐2,4‐diones …”

A Simple Metal-Free Cyclization for the Synthesis of 4-Methylene-3-Substituted Quinazolinone and Quinazolinthione Derivatives: Experiment and Theory

“…m.p. 186~188°C (Sbei et al, 2018, 188~190°C); 1 H NMR (400 MHz, Chloroform- d ) δ 8.18 (s, 1H), 7.59–7.49 (m, 3H), 7.47–7.40 (m, 1H), 7.35–7.28 (m, 2H), 7.24 (dd, J = 7.9, 1.3 Hz, 1H), 7.06–6.96 (m, 1H), 6.72 (dd, J = 8.1, 1.2 Hz, 1H), 4.74 (d, J = 2.2 Hz, 1H), 3.68 (d, J = 2.2 Hz, 1H). 13 C NMR (101 MHz, Chloroform- d ) δ 150.88, 143.31, 138.42, 135.16, 130.27, 129.94, 129.19, 128.34, 123.94, 122.73, 117.03, 115.09, 87.43.…”

“…m.p. 223~225°C (Sbei et al, 2018, 214~217°C); 1 H NMR (400 MHz, DMSO- d 6 ) δ 10.42 (s, 1H), 7.70 (dd, J = 8.1, 1.3 Hz, 1H), 7.64–7.57 (m, 2H), 7.40–7.31 (m, 3H), 7.08–6.96 (m, 2H), 4.83 (d, J = 2.1 Hz, 1H), 3.45 (d, J = 2.1 Hz, 1H). 13 C NMR (101 MHz, DMSO- d 6 ) δ 149.61, 143.63, 138.05, 136.29, 133.00, 131.90, 130.93, 130.27, 124.58, 122.67, 116.54, 115.33, 86.49.…”

“…Molina et al (1993) utilized iminophosphorane and 2 equivalents of isocyanate to form 4-methylen-4 H -3,1-benzoxazine which upon heating undergoes elimination and rearrangement to furnish 3-substituted 4-methenylquinazolinones. There were only two pioneering methodologies for the synthesis of 4-methylen-3,4-dihydroquinazolin-2-ones, one from 1-( o -alkynylaryl)ureas catalyzed by an Au(I)-complex (Scheme 1, top) (Gimeno et al, 2010, 2014a,b) and the other by reaction of 2-aminoacetophenone with the cyanomethyl anion electrogenerated by acetonitrile reduction at a graphite electrode (Scheme 1, middle) (Sbei et al, 2018). However, these reactions suffer from one or more drawbacks, such as expensive catalysts/ligands, harsh reaction conditions and multi-step preparation of raw materials.…”

Catalytic Electrosynthesis of N,O‐Heterocycles – Recent Advances

“…In the past two decades numerous papers reported direct oxidation of substrates such as amine derivatives to synthesize N ‐heterocycles, or direct electrolysis of benzoic acid derivatives to electrochemically synthesize O ‐heterocycles . On the other hand, the efficacy of strong basic species generated in situ through electrolysis of organic aprotic solvents (such as dimethyl sulfoxide, dimethylformamide, and acetonitrile) is well‐established, as is their application in organic synthesis for constructing N ‐heterocycles such as quinazolinones derivatives, imino‐1,3‐thiazolines, and imidazolidinones …”