Egg shell has been utilized as a natural, green, reusable and eco-friendly reagent for the synthesis of spiro[4H-pyran-oxindole] derivatives by one-pot multicomponent reaction of isatins, 1,3-diketones, and malononitrile/ ethyl cyanoacetate. Good functional group tolerance and broad scope of usable substrates are other prominent features of the present methodology.

The reactivity of quinoneimines towards ketene and diphenylketene was examined. N-Phenylbenzoquinoneirnines (I), (2) and also N-phenylnaphthoquinoneimine react with ketene to give the spiro-adducts (5), (7) and (1 1) respectively. These adducts were stable even after prolonged heating in high boiling solvent. Reaction of the above imines with diphenylketene also afforded 13- lactam spiro-a...

The title spiro-compound, C(20)H(16)N(4)O, crystallizes with four independent mol-ecules in the asymmetric unit. In all of them, the oxindole unit is planar, the r.m.s. deviations ranging from 0.07 to 0.08 Å, while the pyrrolinyl ring adopts an envelope conformation (with the N atom representing the flap). In the crystal, adjacent mol-ecules are linked by N-H⋯N and N-H⋯O hydrogen bonds.

In the title compound, C(24)H(21)ClN(4)O(2)S, the two adjacent spiro junctions link an almost planar (r.m.s. deviation = 0.017 Å) 2-oxindole ring, a hexa-hydro-1H-pyrrolizine ring and a tetra-hydro-imidazo[2,1-b]thia-zole ring. In the crystal, inversion dimers linked by pairs of N-H⋯N hydrogen bonds occur, generating an R(2) (2)(16) loop.

A stereoselective cyclization between alkylidene oxindoles and 5-methoxyoxazoles has been developed using catalytic titanium(IV) chloride (as low as 5 mol %) to afford spiro[3,3'-oxindole-1-pyrrolines] in excellent yield (up to 99%) and diastereoselectivity (up to 99:1). Using a chiral scandium(III)-indapybox/BArF complex affords enantioenriched spirooxindole-1-pyrrolines where a ligand-induced...

A diastereo- and enantio-selective domino Michael-cyclization-tautomerization reaction of isatylidene malononitriles with α,α-dicyanoalkenes catalyzed by a cinchona alkaloid-derived bifunctional thiourea catalyst has been developed. A series of multi-functionalized spiro oxindole diene derivatives have been obtained in good to excellent yields (up to 97%) with good to excellent enantioselectivi...

An efficient synthesis of the antitumor alkaloid (+/-)-strychnofoline is documented. Key to the development of the highly convergent strategy delineated is the coupling of a cyclic imine with spiro[cyclopropan-1,3'-oxindole], which takes place in a highly diastereoselective manner. The ability to conduct annulation reactions of spirocyclopropyloxindoles with functionalized cyclic imines provide...

in the present study, the synthesis of diethylene triamine supported on cellulose biopolymer as a biodegradable solid basic heterogeneous catalyst was suggested. then, the applicability of the synthesized catalyst cellulose bonded n-propyl diethylene triamine (cbpdeta) was tested for the synthesis of oxindole derivatives, an important class of potentially bioactive compounds. a various series o...

The chloroform solvate of uncarine C (pteropodine), (1'S,3R,4'aS,5'aS,10'aS)-1,2,5',5'a,7',8',10',10'a-octahydro-1'-methyl-2-oxospiro[3H-indole-3,6'(4'aH)-[1H]pyrano[3,4-f]indolizine]-4'-carboxylic acid methyl ester, C(21)H(24)N(2)O(4).CHCl(3), has an absolute configuration with the spiro C atom in the R configuration. Its epimer at the spiro C atom, uncarine E (isopteropodine), (1'S,3S,4'aS,5'...