The Reaction between β-Keto Esters and Arylamines in the Presence of Polyphosphoric Acid. I. Ethyl Benzoylacetate and Arylamines

Antimalarials. 1. Heterocyclic analogs of N-substituted naphthalenebisoxazines

“…The reductive dehalogenation of 30 and 33 to 31 and 34 was based upon a procedure used for the hydrogenolysis of 3-halo-6,8-dimethoxyisoquinolines. 5 The substitued 4-chloroquinoline (0.05 mol) and 2.0 g of 10% palladium-on-carbon catalyst were mixed in a hydrogenation bottle. Ethanolic potassium hydroxide (1 N, 130 ml) was added to the reaction mixture and it was shaken in a Parr hydrogenator until the theoretical amount of hydrogen was consumed (3-5 hr).…”

2-Aryl-3-acetyl-4(1H)-quinolones1

“…A. By Cyclization of Crotonate I in Liquid Paraffin.-The crotonate (I, 1 g.) was added in one portion to hot (~200°) liquid paraffin (medicinal, 20 g.) and the yellow solution was stirred at ~250°for [20][21][22][23][24][25][26][27][28][29][30] min." During this period reaction proceeded with effervescence and the sparingly soluble quinolone IV usually separated from solution.…”

On the Knorr Synthesis of 6-Bromo-4-methylquinolin-2(1H)-one

“…However, depending on the reaction conditions and the substrates considered, this is often fraught with the occurrence of the corresponding crotonates 5 8 and previous work demonstrated a degree of interconversion possible between them. 1,[9][10][11][12] The occurrence of this mixture was actually the source of some initial confusion regarding the structures of the reaction products 6 and 7. 13 The use of the fairly toxic diketene 3, instead of ethyl acetoacetate, secured the regioselectivity of this step [14][15][16] and a more recent report using tert-butyl acetoacetate 17 can also allay this problem.…”

“…4,5 Interestingly, the use of polyphosphoric acid at 170°C for the preparation of quinolin-4(1H)ones 7 is sometime possible although, depending on the reaction concentration as well as the substrate considered, the isomeric quinolin-2(1H)-ones 6 are sometime obtained. 10,11,[21][22][23]…”