Table 2.

Molecular structures, yield and biological activity against coronavirus (229E) of derivatives 18a–l.

Entry	Compound ID	R	R’	Yield	EC50 (μM)a
1	18a		H	85%	>100
2	18b			74%	>100
3	18c			90%	>100
4	18d			48%	>100
5	18e		-CF3	90%	>100
6	18f			85%	8.9
7	18g			85%	>100
8	18h			89%	>100
9	18i			85%	11.95
10	18j			89%	>100
11	18k		-F	91%	>100
12	18l			57%	>100

^aConcentration required to reduce virus-induced cytopathogenicity by 50%.