Table 1.

Dihydropyridones (4a–j) produced under infrared irradiation^a.

Compound	Melting point[b] (°C)	Yield[c]%
4a	197–198(197–198) [12,28]	75
4b	168–171	75
4c	206–208(207–209) [12,28]	75
4d	184–186(184–186) [29]	70
4e	200–202(201–201) [29]	75
4f	130–133	60
4g	oil	70
4h	oil	60
4i	180–183	55
4j	185–188	50
4k	oil	65
4l	oil	59

^[a]3 hours

^[b]Experimental

^[c]Isolated pure product.