PURPOSE: A compound having an activity of suppressing novel beta-ketoacyl acyl carrier protein synthase III(KAS III) is provided to suppress fatty acid synthesis. CONSTITUTION: A compound having an activity of suppressing novel beta-ketoacyl acyl carrier protein synthase III(KAS III) is denoted by chemical formula 1. A pharmaceutical composition for preventing or treating infectious diseases contains the compound, derivative thereof, or pharmaceutically acceptable salt thereof as an active ingredient.본 발명은 신규한 베타-케토아실 아실기 전달 단백질 생성효소 III (β-Ketoacyl acyl carrier protein synthase III, KAS III) 저해 활성을 가지는 화합물 4-[(3-Chloro-pyrazin-2-yl)-hydrazonomethyl]-benzene-1,3-diol의 용도에 관한 것이다.