Nano-ZnO Catalyzed Multicomponent One-Pot Synthesis of Novel Spiro(indoline-pyranodioxine) Derivatives

Table 1

Experimental data of  7′-amino-2′2′-dimethyl-2,4′dioxo-1,2-dihydrospiro[indoline-3,5′-pyrano[2,3-d]-1′,3′dioxine]-6′-carbonitrile (4a–f)/carboxyethylester (5a–f) under microwave irradiation (Method A) and conventional heating (Method B).

Entry	X	Method A (MW)^a		Method B (Δ)		M.P. (°C)
		Yield	Time	Yield	Time
		(%)	(min.)	(%)	(hrs.)
4a		87	9	62	10	294
4b		85	10	65	11	299
4c		83	10	64	10	305
4d		86	9	63	10	315
4e		81	11	68	9	302
4f		88	9	66	8	318
5a		84	8	65	8	296
5b		85	9	65	9	317
5c		85	9	65	9	325
5d		82	9	68	10	312
5e		84	11	70	9	290
5f		86	10	71	9	319

Reaction conditions: Meldrum’s acid (1.0 mmol), isatin (1.0 mmol), malononitrile/ethylcyanoacetate (1.0 mmol), absolute ethanol (15 mL), and catalyst (30 mg). ^aReaction under microwave irradiation was carried out at 420 watts.