Use of fused ring cyclopentanones and cyclopentenones in...

Details Use of fused ring cyclopentanones and cyclopentenones in... Use of fused ring cyclopentanones and cyclopentenones in...

1999-03-31

2001-01-16

Clardy, S. Mark (Department: 1616)

Plant protecting and regulating compositions

Plant growth regulating compositions

Organic active compound containing

C504S313000, C504S348000

Reexamination Certificate

active

06174840

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to the control of plant growth and is particularly concerned with the use of certain fused cyclopentanones and cyclopentenones in the control of transpiration.
2. Description of the Related Art
There are many circumstances in which the use of plant growth retarding substances can be of considerable practical and economic significance, for example in control of the time of fruit ripening, bud sprouting or seed germination and in control of the extent of stem elongation (e.g. coleoptile growth). A further possible control is of transpiration via the stomatal apertures, thus giving control over the water balance of the plant. Control of the stomata, especially if reversible, can, for example, assist in the adaptation of crops to drought conditions and/or problems of salinity and alkalisation which may result from water shortage.
It has been known for some time that jasmonic acid and its simple carboxylic acid esters, eg methyl jasmonate, are involved in growth control. Thus Thimann et al (1979), Proc. Nat. Acad. Sci. USA, 716, 2295-2298 suggested that since methyl jasmonate is a volatile compound, it could be a volatile hormone involved in regulating the senescence and stomatal aperture of oat leaf segments. The formula (I) of methyl jasmonate is given below.
More recently, a review article by Parthier, J. Plant Growth Regulation (1990), 9, 57-63, in discussing the known stimulatory and inhibitory effects of jasmonic acid and methyl jasmonate, recounts the view that three important structural moieties are necessary for seedling growth inhibition (and probably for any biological activity): the acetoxy side chain, the n-pentenyl chain inserted at C-7, and a keto or hydroxy group at C-6.
It is against this background that a group of fused ring cyclopentanones and cyclopentenones have been found, which do not require all the structural features of methyl jasmonate or jasmonic acid and which surprisingly find application in the inhibition of transpiration.
SUMMARY OF THE INVENTION
Accordingly, the present invention provides the use in inhibiting plant growth, especially in controlling transpiration, of a compound of formula II
in which either the pair of symbols X and Y or the pair of symbols Y and Z, together with the carbon atoms to which they are attached, form a non-aromatic ring system having either 5 or 7 ring atoms, all of which are carbon except that one may be oxygen, and which is substituted or unsubstituted, R
1
represents a hydrogen atom or an alkyl or a substituted or unsubstituted phenyl group and R
2
represents a hydrogen atom and R
3
an alkyl carboxymethyl group or R
2
and R
3
together form a double bond, and thereafter any unsatisfied valencies of ring carbon atoms of the cyclopentanone or cyclopentenone ring shown in formula II are satisfied by hydrogen atoms.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
X and Y or Y and Z preferably complete a cyclopentane, cycloheptane, [2.2.0] bicyclohexene or a tetrahydrofuran ring, substituted or unsubstituted.
R
1
is preferably an alkyl group of 1 to 6 carbon atoms, especially of 1 to 5 carbon atoms and preferably straight-chained or a phenyl, p-alkoxyphenyl or p-alkylcarbonylphenyl group in which the alkoxy and alkyl groups have 1 to 4 carbon atoms. p-Methoxyphenyl and p-Methylcarbonylphenyl (=p-acetylphenyl) are the preferred p-substituted phenyls.
When Y and Z represent a fused ring as defined above and simultaneously R
2
and R
3
represent a double bond, X is hydrogen in order to satisfy the unsatisfied valency in the ring of formula (II). When X and Y represent a fused ring as defined above and simultaneously R
2
is hydrogen and R
3
is alkyl carboxyalkyl, Z is hydrogen in order to satisfy the unsatisfied valency.
One preferred group of compounds for use in the composition of the invention is that in which X and Y or Y and Z together with the carbon atoms to which they are attached form a tetrahydrofuran ring, especially a tetrahydrofuran (THF) ring fused at the 3 and 4 positions to the cyclopentanone or cyclopentenone ring. Examples of such compounds are fused THF-cyclopentenones where R
1
is alkyl, especially of 1 to 6 carbon atoms, most especially of 1 to 5 carbon atoms, and/or where the THF ring is substituted at the 2-position, e.g. by dimethyl. Other examples are fused THF-cyclopentanones in which R
2
is hydrogen and RW is alkyl carboxymethyl. Preferably the alkyl groups of RW have from 1 to 4 carbon atoms.
Another preferred group of compounds for use in the invention are those of formula II in which X and Y together represent —CH
2
—(CH
2
)
n
—CH
2
— where n is 1 or 3, thus completing a cyclopentan or cycloheptane ring and R
1
represent an alkyl group of 1 or 3, thus 6 carbon atoms or a phenyl, p-alkoxyphenyl or p-alkylcarbonylphenyl in which the alkoxy and alkyl groups have 1 to 4 carbon atoms.
Where X and Y together represent a [2.2.0]bicyclohexene ring system, the double bond is preferably symmetrically disposed, i.e. it is a [2.2.0]bicyclohex-l-ene fused at the carbon atoms 4 and 5 as shown in Example 16.
Substituents R
2
and R
3
are preferably in the trans-configuration.
It will be appreciated that the compounds of formula II can exist in different stereoisomeric forms, the use of each of which is intended to be included within the present invention.
The preparation of the cyclopentanones and cyclopentenones of formula II can be conveniently effected employing the Khand reaction as described by Billington et al., (1988) J. Chem. Research (S) 326-327, (M) 2601-2622.
The Khand reaction requires co-cyclisation of alkynes with alkenes and carbon monoxide via an alkyne-octacarbonvldicobalt complex to give a cyclopentenone. The methods described by Billington et al may be employed to prepare various bicyclic and tricyclic compounds of formula II. In order to improve yields and extend the usefulness of the reaction the method may be accelerated by the use of amine oxides as described by Jeong et al, (1991), Synlett, 204 and Shambayati et al (1990),
Tetrahedron Letters
, 31, 5289.
Thus compounds where Y and Z together form a bicyclic or tricyclic ring structure are generally described by Jeong et al. Compounds where X and Y together form the ring structure are generally described by Billington et al.
The compounds of formula II have been found to demonstrate an effect on transpiration of plants by inducing stomatal closure.
The induction of stomatal closure is a prerequisite of antitranspirant activity. In plants, loss of water from leaf surfaces (transpiration) occurs through the stomatal pores (ca 95%); losses from the cuticle surfaces are minimal (ca 5%). The size of the stomatal pore is determined by the size and turgor of the guard cells which surround the pore; normally the pores exhibit a diurnal fluctuation, being open during daylight and closed at night. Loss of water is compensated by absorption of water by the roots and its movement via the xylem to the leaves. Inadequate water absorption due to drought or salinity may cause water stress and at least loss of crop productivity. Increasing frequency of drought and salinity on a world scale underlines the potential importance of a suitable antitranspirant.
The compounds were further found to exert an effect on other factors affecting growth, in particular shoot growth, as exemplified by indole-3-acetic acid (IAA) induced coleoptile growth.
The active compounds of formula II can be utilised, if desired, in the form of the usual formulations or compositions with one or more conventional inert (i.e. plant compatible or herbicidally inert) agricultural or horticultural carriers, e.g. conventional dispersible carrier vehicles such as gases, solutions, emulsions, wettable powders, suspensions, powders. dusting agents, foams, pastes, soluble powders, granules, aerosols, suspension-emulsion concentrates, seed-treatment powders, natural and synthetic materials impregnated with active compound, very fine capsules in polymeric substances and in co

Affiliated with

Also associated with

Rating

Use of fused ring cyclopentanones and cyclopentenones in... does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Use of fused ring cyclopentanones and cyclopentenones in..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Use of fused ring cyclopentanones and cyclopentenones in... will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2530328