Degradation of the Herbicide Alachlor by Soil Microorganisms II. Synthesis and Phytotoxicity of Major Degradation Products

제초제 Alachlor 의 토양미생물에 의한 분해 II. 주요 분해산물의 합성과 식물독성

Two of the degradation products of alachlor in soil. product 1, 2,6-diethyl-N-(methoxymethyl) acetanilide and product 2,2-hydroxy-2',6'-diethyl-(methoxymethyl) acetanilide were synthesized from alachlor reacting with 3N-hydrochloric acid in the presence of zinc powder at room temperature and a saturated sodium bicarbonate solution at $90^{\circ}C$ for 78 hr, respectively. At the concentrations of both $5{\times}10^{-4}M\;and\;1{\times}10^{-3}M$, product 2 exhibited almost the same phytotoxicity to rice seedlings, in particular, as alachlor, whereas product 1 lost its phytotoxic effectiveness. It seems that substitution of chlorine atom by hydroxyl group did not affect the phytotoxicity of alachlor, whereas substitution by hydrogen atom did.

Alachlor의 토양중 분해산물인 2,6-diethyl-N-(methoxymethyl) acetanilide(분해산물 1)와 2-hydroxy-2',6'-diethyl-N-(methoxymethrl) acetanilide (분해산물 2)를 합성하였다. 분해산물 1은 실온에서 아연분말 존재하에 alachlor를 3N-염산과 반응시켜서 얻었고 분해산물 2는 alachlor를 중탄산소다의 포화용액과 $90^{\circ}C$에서 78시간 반응시켜 합성하였다. 분해산물 2는 $5{\times}10^{-4}M$와 $1{\times}10^{-3}M$의 농도에서 특히 어린벼에 alachlor와 거의 같은 독성을 보인 반면 분해산물 1은 그 약효를 상실하였다. 따라서 alachlor 구조중의 염소원자를 수산기로 치환해도 alachlor의 식물독성은 별 영향을 받지 않으나 수소원자로 치환할 경우는 영향을 받는 것으로 보인다.