(+)-CSA Catalyzed Multicomponent Synthesis of 1-[(1,3-Thiazol-2-ylamino)methyl]-2-naphthols and Their Ring-Closure Reaction under Ultrasonic Irradiation

Table 3

(+)-CSA catalyzed one-pot three-component Mannich reaction of 2-naphthol with 2-aminothiazole and aromatic aldehydes (see Scheme 3).

Product	R	Time (min)	Yield (%)
1a	Phenyl	30	90
1b	4-Methylphenyl	30	76
1c	4-Bromophenyl	45	70
1d	4-Isopropylphenyl	30	87
1e	2,4-Dimethylphenyl	30	74
1f	2,4-Dichlorophenyl	45	72
1g	2,4-Difluorophenyl	45	75
1h	3-Phenoxyphenyl	30	83
1i	4-Benzyloxyphenyl	30	86
1j	3-Nitrophenyl	30	68
1k	Thiophen-2-yl	30	75
1l	Thiophen-3-yl	30	70
1m	5-Methylfuran-2-yl	30	88
1n	5-Bromofuran-2-yl	30	81

Isolated yield.