Preparation and Thermal Rearrangement of Alkenyl 3-Alkenyloxy-2-butenoates. Catalysis of the Aliphatic Claisen Rearrangement by Ammonium Chloride

Ammonium Chloride Catalysed One-pot Multicomponent Synthesis of 1,8-dioxo-octahydroxanthenes and N-aryl-1,8-dioxodecahydroacridines Under Solvent Free Conditions

“…It has been reported to act as an effective catalyst in carrying out Claisen rearrangement, 19 Biginelli reaction, 20 one-pot synthesis of diindolymethanes, 21 thia-Michael addition, 22 etc. 23 We now wish to extend the synthetic applicability of this unique catalyst in the one-pot synthesis of both 1,8-dioxo-octahydroxanthene (3) and N-aryl 1,8-dioxo decahydroacridine (5) Initially, we optimised the reaction conditions with the synthesis of 1,8-dioxo-octahydroxanthene moiety (3), and for this purpose a set of standard reaction conditions were established on the basis of a series of trial reactions of benzaldehyde (1a) and 5,5-dimethylcyclohexane-1,3-dione (dimedone; 2) in the presence or absence of ammonium, sodium and potassium halides under solvent or neat condition at varying temperatures to obtain 3,3,6,6-tetramethyl-9phenyl-3,4,5,6,7,9-hexahydro-1H-xanthene-1,8(2H )-dione (3a) ( Table 1).…”

Ammonium chloride; as a mild and efficient catalyst for the synthesis of some 2-arylbenzothiazoles and bisbenzothiazole derivatives

“…Ammonium chloride (NH4Cl) is a very inexpensive, eco-friendly and easily available catalyst; it has been reported as catalyst for synthesis of various organic compounds. It has effectively promoted Claisen rearrangement [28], Biginelli synthesis of 3,4-dihydropyrimidinones [29], the thia-michael addition reaction [30], the one-pot synthesis of diindolymethanes [31], and the synthesis of Quinoxalines [32].…”

Recent progress of Ammonium chloride as catalyst in organic synthesis

“…2 The ethers 1 and 2 gave allyl 2-allyl-3-oxobutanoate 3 and crotyl 2-(1-methyl-2-propenyl)-3-oxobutanoate 4 respectively in good yield. The intramolecularity of the rearrangement was also demonstrated by heating a mixture of 1 and 2 in presence of Ammonium chloride.…”