Synthesis and herbicidal activity of optically active ethyl 2-[4-(6-chloro-2-quinoxalinyloxy) phenoxy] propanoate

• Published in: Journal of Pesticide Science Vol. 10; no. 1; pp. 69 - 73
• Main Authors: Sakata, G, Makino, K, Morimoto, K, Ikai, T, Hasebe, S. (Nissan Chemical Industries Ltd., Tokyo (Japan))
• Format: Journal Article
• Language: English; Japanese
• Published: Tokyo Pesticide Science Society of Japan 01.01.1985; Japan Science and Technology Agency
• Subjects: ACCION DEL PLAGUICIDA; ACTION DES PESTICIDES; CHEMICAL STRUCTURE; COMPOSE ORGANOCHLORE; COMPUESTO ORGANICO DEL CLORO; ESTRUCTURA QUIMICA; HERBICIDAS; HERBICIDE; HERBICIDES; OPTICAL PROPERTIES; ORGANOCHLORINE COMPOUNDS; PESTICIDE ACTIONS; PROPIEDADES OPTICAS; PROPRIETE OPTIQUE; STRUCTURE CHIMIQUE
• ISSN: 0385-1559; 1348-589X; 1349-0923
• DOI: 10.1584/jpestics.10.69

Optically active ethyl (R)-(+) and (S)-(-)-2-[4-(6-chloro-2-quinoxalinyloxy) phenoxy]-propanoate ((R)-(+)-1 and (S)-(-)-1) were synthesized from (S)-(+)-lactic acid: (S)-(+)-lactic acid was converted to ethyl O-(p-toluenesulfonyl)-(S)-(-)-lactate, ethyl O-methane-sulfonyl-(S)-(-)-lactate, ethyl (R)-(+)-2-chloropropanoate and ethyl-(R)-(+)-2-bromopro-panoate, respectively. Each intermediate was condensed with 4-(6-chloro-2-quinoxalinyloxy)-phenol (2) to afford (R)-(+) and (S)-(-)-1. Optical purities were determined by the 200MHz 1H NMR spectroscopic measurement using shift reagent, Eu(HFC)3. It was assumed that optically pure (R)-(+)-1 would have [α]20D+35.2°(CHCl3, c=1.20%). The growth inhibiting activity against rice plants in petridish and the post-emergence herbicidal activity against Setaria viridis were examined. The strong correlation was observed between the content of (R)-(+)-isomer and biological activity. It was assumed that optically pure (R)-(+)-1 was approximately two fold more active than the racemate and optically pure (S)-(-)-1 was low active or inactive.