Green chemistry approaches to the regioselective synthesis of spiro heterobicyclic rings using iodine as a new and efficient catalyst under solvent-free conditions

Abstract

Iodine catalyzes the pseudo four-component reaction of an aldehyde, a urea or thiourea, and cyclic 1,3-dicarbonyl compounds under microwave irradiation in a solvent-free condition to yield various σ symmetric spiro heterobicyclic rings in excellent yields.

KF/Al<SUB>2</SUB> O<SUB>3</SUB> promoted aza-Michael addition of 4-aryl-7,7-dimethyloctahydroquinazolinones to α, β-ethylenic compounds

“…After the reaction was completed (monitored by TLC), pure product was obtained from the crude product by filtration and recrystallisation to afford 2,3,4,5,6,7, 8, 152.4, 151.9, 144.6, 128.3, 127.1, 126.2, 107.4, 52.0, 51.9, 49.8, 32.3, 28.7, 26.8 2,3,4,5,6,7, 6,174.6,148.7,143.3,128.5,127.5,126.4,108.1,52.2,52.1,49.8,32.2,28.8,26.7. MS (FAB): m/z = 286 (M + +H).…”

“…Calcd for C 20 H 24 N 2 O 4 : C,67.40;H,6.79;N,7.86. Found: C,67.62;H,6.73;N,2,3,4,5,6,7, -7,7-dimethyl-1,2,3,4,5,6,7,8-octahydroquinazoline-2,5- 6, 152.9, 151.2, 141.2, 139.5, 129.4, 127.8, 110.2, 58.4, 53.5, 50.8, 48.4, 39.6, 33.7, 32.9, 28.7, 27.4, 22.0 -7,7-dimethyl-1,2,3,4,5,6,7,8-octahydroquinazoline-2,5- 194.2,173.6,154.8,152.3,140.2,134.7,129.6,128.7,109.4,59.3,51.7,52.6,44.6,40.7,31.5,33.2,29.5,27.2. MS (FAB): m/z = 390, 392 (M + +H).…”

“…Found: C,59.95;H,5.70; N, 10.53%. 1,2,3,4,5,6,7,8-octahydroquinazoline-2-one/thione-5- 2,3,4,5,6,7, 7.38 (d,J = 8.0 Hz,1H,C 6 H 4 ),1H,C 6 H 4 ),2H,C 6 H 4 ),5.66 (s,1H,CH), 3.88 (s,3H,OCH 3 ),1H,CH 2 ),1H,CH 2 ),1H,CH 2 ),1H,CH 2 ),4H,2CH 2 ), 1.11 (s,3H,CH 3 ) , 1.00 (s, 3H, CH 3 ). 13 C NMR (CDCl 3 ): δ = 197.…”

“…Calcd for C 20 H 23 N 2 ClO 4 : C,61.46;H,5.93;N,7.17. Found: C,61.57;H,5.98;N,2,3,4,5,6,7, 7.92 (br,1H,NH),5H,C 6 H 5 ),5.62 (s,1H,CH),1H,CH 2 ),2H,OCH 2 ),1H,CH 2 192.6,171.6,153.8,146.3,144.1,128.8,128.2,128.3,109.8,63.7,59.7,50.6,48.9,40.1,32.9,31.9,30.4,29.5,27.5,19.6,14.9. MS (FAB): m/z =398 (M + +H).…”

“…2 In recent years, interest has been focused on Biginelli-like reactions in which open chain β-dicarbonyl compounds have been extended to cyclic β-diketones, β-ketolactones, β-diamides, or cyclic β-diesters, benzocyclic ketones, and α-keto acids under a variety of conditions, and the heterocycles thus obtained exhibit a wide range of biological activities, such as antiviral, antitumour, antihypertensive, and neuropeptide Y(NPY) antagonism. [3][4][5][6][7] Among the synthetic products via Biginelli reaction, octahydroquinazolin-5-one derivatives are interesting compounds because of their wide range of biological activities. Octahydroquinazolinones have exhibited potent antibacterial activity 8,9 and calcium antagonist activity.…”