Chapter 4 Synthesis and Fungicidal Properties of Cyclopropanecarboxamides Downloaded by OHIO STATE UNIV LIBRARIES on September 17, 2012 | http://pubs.acs.org Publication Date: December 28, 2000 | doi: 10.1021/bk-2001-0774.ch004
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Katsuaki Wada , Gerd Hänβler , Shinzo Kagabu , Udo Kraatz , Yoshio Kurahashi , and Haruko Sawada 1
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Yuki Research Center, Nihon Bayer Agrochem Κ. K., Yuki, Ibaraki 307-0001, Japan Landwirtschaftszentrum Monheim, Bayer AG, D-40789 Monheim, Germany Department of Chemistry, Faculty of Education, Gifu University, Gifu 501-1193, Japan
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Carpropamid (WIN ) is a newly-launched fungicide for controlling rice blast. This compound belongs to a new chemical class of cyclopropanecarboxamides which has been jointly developed by Nihon Bayer Agrochem K . K . and Bayer AG. Carpropamid is classified as a melanin biosynthesis inhibitor (MBI). Compared with other MBIs already on the market, carpropamid has a completely new mode of action, i.e., the inhibition of the dehydration of scytalone to 1,3,8-tri hydroxynaphthalene or of vermelone to 1,8-dihydroxy naphthalene in the melanin biosynthesis pathway of Pyricularia oryzae.
Introduction Carpropamid is a new fungicide offering protection against Pyricularia oryzae, rice blast. This compound belongs to a new class of fungicides, the
© 2001 American Chemical Society
In Agrochemical Discovery; Baker, D., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 2000.
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cyclopropanecarboxamides, and has a completely new mode of action in contrast to conventional rice blasticides. Carpropamid exhibits excellent protective and systemic efficacy over an extremely long period. These favourable characteristics led us to develop this compound for nursery box applications in controlling both leaf and panicle blast.
Downloaded by OHIO STATE UNIV LIBRARIES on September 17, 2012 | http://pubs.acs.org Publication Date: December 28, 2000 | doi: 10.1021/bk-2001-0774.ch004
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Chemical name :(l^S,3 S'i?)-2,2-dichloro-#-[l-(4-chlorophenyl)ethyl]-lethyl-3-methyleyclopropaneearboxamide Tradename :WIN (Launched 1998) Common name : Carpropamid Code No. : K T U 3616, N T N 33853 1
Figure L Carpropamid: Structure and Nomenclature
Protective Value • Leaf blast • Panicle blast Carpropamid 4%GR 50g/box nursery box application on May 7
Probenazole 8%GR 30kg/ha submerging on June 17 followed by Kasugamycin & fthalide 0.1&1.5% DL 40kg/ha dusting on Aug. 2 and 9
Field location: Sendai Miyagi, Japan. Crop and variety: Rice (Sasanishiki). Transplanting: May 9, 1994. 2
Plot size: 960m . Assessment: Leaf blast, July 31, Panicle blast, Aug. 30. Damage degree in the untreated plot: Leaf blast (2.5), Panicle blast (1.2)
Figure 2. Ffficacy of Carpropamid against Leaf and Panicle Blast in the Field
In Agrochemical Discovery; Baker, D., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 2000.
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Downloaded by OHIO STATE UNIV LIBRARIES on September 17, 2012 | http://pubs.acs.org Publication Date: December 28, 2000 | doi: 10.1021/bk-2001-0774.ch004
In Japan, transplanting of nursery plants to the paddy field by transplanting machine is the major method used in rice cultivation. The nursery box application has two advantages. The first is a reduction in manual labour, the second is the decreased environmental risk through lower application rates of the. active ingredient. As shown in Figure 2, carpropamid affords excellent efficacy against both leaf and panicle blast following a single application.
History of the Discovery In 1972, researchers at Shell applied for a patent in which 2,2-dichloro-3,3dimethylcyclopropanecarboxylic acid, WL 28325, was described as a potent blasticide(/). In 1977, Cartwright reported this acid induced phytoalexins, momilactone A and B, when penetration of rice blast started(2). This interesting information led us to explore dichlorocyclopropane chemistry, starting in the early 80s.
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W L 28325 (Shell)
Figure 3. Research Focus on Cyclopropanes
The evolution of our chemistry is depicted in Figure. 3. Until the mid-80s, we concerned ourselves with the chemistry of dichlorocyclopropanecarboxylic acid itself and closely related compounds. Then we found that the otmethylbenzylcyclopropanecarboxamides were an interesting group to be investigated for blasticidal activity, and intensive research was conducted in this area(5, 4). The third period is concerned with the stereoisomers which we have been studying until now(4-
