To provide a new compound useful as a plant blight controlling agent especially for the control of rice blast.
The objective compound is expressed by the formula I (X is a halogen; R1 is a 1-4C alkyl; R2 is OR3 or N(R4)(R5); R3 is H, a 1-10C alkyl, etc.; R4 and R5 are each H, a 1-10C alkyl or together form a 3-8C cycloalkylene), e.g. 3-chloro-1-methyl-5-ethoxycarbonyl-4,5-dihydro-pyrazole. The compound of the formula I can be produced by reacting a fumaric acid diester or a maleic acid diester of the formula II with a monoalkylhydrazine of the formula, R1 NHNH2, cyclizing the produced addition product by heating to obtain a 3- hydroxypyrazoline derivative of the formula III and reacting with a halogenation agent (e.g. phosphorus oxychloride). The agent is effective against melanose of orange, brown rot of peach, late blight of tomato, leaf spot of peanut, black spot of rose, etc., in addition to rice blast.
SUZUKI HIROYUKI
YASUMI YOSHIAKI
UTSUNOMIYA TOMOHISA
WATANABE JUNICHI
OYA HIROSHI
NISHIOKA MASANORI
FURUSATO TAKASHI
