# US 4,397,678 A · Plant growth regulators

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- Number: US 4,397,678 A
- Document ID: US4397678A
- Status: Granted
- Kind: A
- Application number: 06/343,090
- Filed: 1982-01-27
- Granted: 1983-08-09
- Earliest claimed: 1979-05-31
- Assignees: Toshihiko Okamoto; Yo Isogai; Koichi Shudo; Susumu Sato
- Inventors: Toshihiko Okamoto; Yo Isogai; Koichi Shudo; Soshiro Takahashi
- Web page: https://patentgrep.com/patent/US4397678A

## CPC

- A01N 47/36: containing the group >N—CO—N< directly attached to at least one heterocyclic ring; Thio analogues thereof
- C07D 237/20: Nitrogen atoms (nitro radicals C07D237/12)
- A01N: PRESERVATION OF BODIES OF HUMANS OR ANIMALS OR PLANTS OR PARTS THEREOF (preservation of food or foodstuff A23); BIOCIDES, e.g. AS DISINFECTANTS, AS PESTICIDES OR AS HERBICIDES (preparations for medical, dental or toiletry purposes which kill or prevent the growth or proliferation of unwanted organisms A61K); PEST REPELLANTS OR ATTRACTANTS; PLANT GROWTH REGULATORS
- C07D: HETEROCYCLIC COMPOUNDS (macromolecular compounds C08)

## Abstract

Plant growth regulators of the N-(4-pyridazinyl)urea and thiourea type are disclosed which exhibit excellent cytokinin-like activities and are useful for regulating plant growth in various manners, such as acceleration and suppression.

## Claims

### Claim 1

An agricultural composition useful as a plant growth regulator comprising as an active ingredient a compound of formula: ##STR5## wherein R.sub.1 and R.sub.2, which may be the same or different, each represents a hydrogen atom, a lower alkyl group, a halogen atom, a lower alkoxy group, an aryloxy group, a halomethyl group, a cyano group, an alkylthio group, a carboxy group or an alkoxycarbonyl group; X represents an oxygen atom or a sulfur atom; and n represents 1, 2 or 3; and when n is 2 or 3, R.sub.1 and R.sub.2 each may be different, in an effective plant-growth regulating amount, together with an inert carrier or diluent.

### Claim 2 (depends on 1)

The agricultural composition of claim 1 wherein said active ingredient is contained in a concentration of about 0.000001 ppm to about 1%.

### Claim 3 (depends on 1)

The agricultural composition of claim 1 wherein said active ingredient is selected from N-(4-pyridazinyl)-N'-phenylurea and N-(4-pyridazinyl)-N'-(m-fluorophenyl)urea.

### Claim 4

A method of controlling plant growth which comprises contacting a plant or a part thereof with a compound of formula: ##STR6## wherein R.sub.1 and R.sub.2, which may be the same or different, each represents a hydrogen atom, a lower alkyl group, a halogen atom, a lower alkoxy group, an aryloxy group, a halomethyl group, a cyano group, an alkylthio group, a carboxy group or an alkoxycarbonyl group; X represents an oxygen atom or a sulfur atom; and n represents 1, 2 or 3; and when n is 2 or 3, R.sub.1 and R.sub.2 each may be different, in an amount effective for regulation of the growth of the plant involved.