Benzaldehyde acetal compounds, preparation process thereof, and herbicidal compositions containing the same as active ingredients

Benzaldehyde acetal compounds represented by the following formula: ##STR1## in which each R is a C.sub.3-8 alkyl group and forms an ether bond with the corresponding oxygen atom of the orthoaldehyde moiety have no injury to crops and, moreover, exhibits superb herbicidal effects owing to the limitation of the number of carbon atoms of each alkyl group to 3-8.

BACKGROUND OF THE INVENTION 
(1) Field of the Invention 
The present invention relates to novel benzaldehyde acetal compounds, a 
process for the preparation thereof, and herbicidal compositions 
containing one or more of the compounds as an active ingredient. 
(2) Description of the Related Art 
Pyrimidine derivatives having a phenoxy group at the 2-position are known 
to possess herbicidal activities as disclosed, for example, in Japanese 
Patent Laid-Open No. 258467/1988 as well as U.S. Pat. Nos. 4,985,066 and 
4,770,971. 
2-(4,6-Dimethoxypyrimidin-2-yloxy)-3-chlorobenzaldehyde dimethylacetal and 
2-(4,6-dimethoxypyrimidin-2-yloxy)-3,5-dichlorobenzaldehyde dimethylacetal 
are exemplied in U.S. Pat. No. 4,985,066. 
However, these dimethylacetals are not fully effective against weeds and, 
moreover, cause severe injury on crops. They are hence impractical. 
SUMMARY OF THE INVENTION 
An object of the present invention is to provide a compound which can 
exhibit excellent herbicidal effects against weeds without injury to 
crops. 
The present inventors have proceeded with an extensive investigation with a 
view toward attaining the above object. As a result, it has been found 
that benzaldehyde acetal compounds having a C.sub.3-8 alkyl group show 
reduced injury to crops such as soybean and cotton, exhibit a 
characteristic herbicidal spectrum centering around johnsongrass, 
shattercane, barnyardgrass (Echinochloa crusgalli), crabgrass (Digitaria 
adsoendens), Imperata cylindrica and Amaranth (Amaranthus viridis), and 
have excellent control effects against johnsongrass emerging from rhizome 
formed therein, leading to the completion of this invention. 
The benzaldehyde acetal compounds of the present invention are represented 
by the following formula (I): 
##STR2## 
wherein R represents a linear or branched C.sub.3-8 alkyl group. 
Dimethyl- or diethylacetal compounds cause severe crop injury and, 
moreover, their herbicidal effects against weeds are insufficient. It has, 
however, been found that the acetal compounds represented by the formula 
(I) and containing C.sub.3-8 alkyl groups have such low crop phytotoxicity 
as to not cause problem in practice and, moreover, have sufficient 
herbicidal effects against weeds. Their herbicidal effects against weeds 
show a characteristic spectrum. In particular, it is to be noted that they 
show extremely good effects against gramineous weeds - such as 
johnsongrass, shattercane and Imperara cylindrica - especially 
johnsongrass emerging from rhizome compared to conventional herbicides. 
Herbicidal compositions containing one or more of the compounds of (I) have 
practically trouble-free phytotoxicity to crops such as soybean and 
cotton, show excellent control effects against johnsongrass with rhizome 
formed therein, said johnsongrass being said to be hardly controllable, by 
known herbicides and have the characteristic spectrum centering around 
shattercane, barnyardgrass (Echinochloa crusgalli), crabgrass (Digitaria 
adscendens), Imperata cylindrica Amaranth (Amaranthus viridis). Further, 
the herbicidal compositions according to this invention can show 
performance surpassing comparative chemicals such as the known compounds 
disclosed in the publications referred to above and other known compounds 
and are extremely useful herbicides. 
DETAILED DESCRIPTION OF THE INVENTION AND PREFERRED EMBODIMENTS 
The benzaldehyde acetal compounds represented by formula (I) are 
characterized in that each alkyl group forming an ether bond with its 
corresponding oxygen atom in the orthoaldehyde moiety has 3-8 carbon atoms 
and, owing to this characteristic feature, they have significantly reduced 
phytotoxicity to crops and excellent herbicidal effects against weeds. 
Compounds of the present invention can be prepared according to the 
following reaction scheme: 
##STR3## 
The steps (b) and (c) are carried out under exactly the same conditions. 
Namely, the compound (VII) can be prepared by heating 
2-hydroxybenzaldehyde represented by the formula (II) and 
2-chloro-4,6-dimethoxypyrimidine represented by the formula (VI) in an 
inert solvent, in the presence of a base, within the temperature range of 
from 50.degree. C. to the boiling point of the solvent, for 1-10 hours. 
Illustrative of the base include alkali metals such a metallic sodium and 
metallic potassium; alkali metal hydroxides such as sodium hydroxide and 
potassium hydroxide; and alkali metal carbonates such as sodium carbonate 
and potassium carbonate. 
Exemplary solvents include aromatic hydrocarbons such as benzene, toluene 
and xylene; ethers such as tetrahydrofuran, dioxane and diglyme; ketones 
such as acetone and methyl ethyl ketone; aprotonic polar solvents such as 
dimethylformamide, dimethylacetamide, dimethylimidazolidinone and 
dimethylsulfoxide; acetonitrile; and water. 
The steps (a) and (d) can be conducted according to the method described in 
Japanese Patent Laid-Open No. 13534/1983. In general, processes for 
converting an aldehyde group to an acetal group can be applied. These 
processes will next be described specifically. 
(1) Process in which an alcohol is reacted in the presence of an acid 
catalyst: 
A corresponding alcohol is reacted in the presence of an acid. The alcohol 
can be used in an amount ranging from its stoichiometric amount to a large 
excess, the latter including the portion employed as a solvent. When an 
alcohol is used in a stoichiometric amount, a solvent inert to the 
reaction can be used. Illustrative of the solvent are aromatic 
hydrocarbons such as benzene, toluene and xylene; ethers such as 
tetrahydrofuran, dioxane and diglyme; aprotonic polar solvents such as 
dimethylformamide, dimethylacetamide, dimethylimidazolidinone 
dimethylsulfoxide; and acetonitrile. 
Illustrative of the acid are mineral acids such as hydrochloric acid and 
sulfuric acid; and organic sulfonic acids such as methanesulfonic acid, 
benzenesulfonic acid and p-toluenesulfonic acid. The reaction temperature 
may range from 0.degree. C. to the boiling point of the solvent used. It 
is however desirable to conduct the reaction within the range of from 
20.degree. C. to the boiling point. The reaction can generally be brought 
to completion in 1-10 hours although the reaction time varies depending on 
the reaction temperature. 
(2) Process in which an orthoformate ester is reacted: 
An acetal can also be obtained easily by reacting a corresponding 
orthoformate ester. The orthoformate ester can be used in an excess amount 
including a portion employed as a solvent, or the corresponding alcohol 
can be employed as a solvent. Other solvent inert to the reaction may also 
be used in some instances. In many cases, the reaction tends to smoothly 
proceed by the addition of a weakly acidic substance such as ammonium 
chloride as a catalyst. It is desirable to conduct the reaction at a 
temperature of from 50.degree. C. to the boiling point, although the 
reaction temperature may range from 0.degree. C. to the boiling point. The 
reaction is generally brought to completion in 2-8 hours. 
Herbicidal compositions of the invention, which contain one or more of the 
benzaldehyde acetal compounds represented by formula (1), act extremely 
effectively against most harmful weeds which cause problems in paddy 
fields or upland fields. In paddy fields, they show extremely good 
herbicidal effects against very troublesome gramineous weeds such as 
barnyardgrass, Leersia oryzoides and common reed; very troublesome 
cyperaceous weeds such as Cyperus microiria, smallflower umbrellaplant, 
Cyperus seroyinus, bulrush, Scirpus nipponicus, Eleocharis kuroguwai, 
Needle spikerush and Fimbristylis miliacea; very troublesome arrowhead 
weeds such as Sagittaria pygmaea, arrowhead and Alisma canalicularum; and 
broadleaf weeds such as Monochoria vaginalis, toothcup and Oenanthe 
javanica. In upland fields, they exhibit superb herbicidal effects against 
broadleaf weeds such as common chickweed, common lambsquarters, shepherd's 
purse, amaranth, hemp sesbania and velvetleaf; gramineous weeds such as 
barnyardgrass, green foxtail, large crabgrass, goosegrass, annual 
bluegrass, blackgrass, oat, wild oat, quack-ammonium grass, downy brome, 
bermudagrass, creeping bentgrass, broomsedge, silky bentgrass, fall 
panicum, johnsongrass, shattercane and woolly cupgrass; cyperaceous weeds 
such as rice flatsedge; especially perennial intractable weeds such as 
johnsongrass, shattercane and orchardgrass. 
In an enzyme-level inhibitory activity test on ALS (acetolactate syntase), 
which is believed to be a target site by the compounds of the invention 
represented by formula (1), the herbicidal compositions containing one or 
more of the compounds of the invention have been found to show high 
inhibitory activities against weeds such as barnyardgrass, johnsongrass 
and green foxtail, as will be understood from the results of the test to 
be described later under Test 1. In contrast, they do not show inhibitory 
activities against broadleaf crops such as pea, cotton and peanut. These 
results indicate that pea, cotton, peanut and the like show high tolerance 
against the herbicidal compositions according to the invention. In pot 
tests, they were also found to show no injury or extremely slight injury 
against crops such as corn, soybean, cotton, beet, peanut, common 
sunflower, rape, potato and greens. Depending on the method of 
application, they can also be used, without any injury, for gramineous 
crops such as wheat, rice, barley and sugar cane. It is however to be 
noted that use of the herbicidal compositions of the invention is not 
limited to these crops. 
The herbicidal compositions containing one or more of the compounds of the 
invention, which are represented by formula (1), are effective in all 
application methods such as soil application, soil incorporation, foliar 
application and band application. They can be used at an application rate 
in the wide range of from 0.01 kg/ha to 10 kg/ha in terms of active 
ingredient. As a standard, it is however preferred to use them at an 
application rate of from 0.1 kg/ha to 5 kg/ha. 
Upon application of the compounds of the formula (1) according to this 
invention as herbicides, they may be applied neat to weeds to be treated. 
In general, they are however mixed with an inert liquid carrier or solid 
carrier and are formed into a commonly-used formulation such as powder, 
granules, wettable powder, emulsion or flowable formulation. One or more 
auxiliary agents can also be added if necessary for formulation. 
Any carrier can be used as long as it is usable in conventional 
agricultural or horticultural chemicals, no matter whether it is solid or 
liquid. No particular limitation is therefore imposed on the carrier. 
Exemplary solid carriers include mineral powders such as clay, talc, 
bentonite, calcium carbonate, diatomaceous earth and white carbon; 
vegetable powders such as soybean flour and starch; high molecular 
compounds such as petroleum resins, polyvinyl alcohol and polyalkylene 
glycols; urea; and waxes. Illustrative liquid carriers include various 
organic solvents such as xylene, methylnaphthalene and alkylbenzenes; 
various oils such as vegetable oils; and water. 
As auxiliary agents, surfactants, binders (e.g., lignine sulfonic acid, 
alginic acid, polyvinyl alcohol, gum arabic, sodium CMC), stabilizers 
(e.g., phenol compounds, thiol compounds and higher fatty acid esters for 
the prevention of oxidation; phosphate salts as pH regulators; and in some 
instances, light stabilizers), and the like--which are generally used in 
agricultural or horticultural chemicals--can be used either singly or in 
combination. In some instances, industrial fungicides, antiseptics and the 
like can also be incorporated for the control of bacteria and fungi. 
As exemplary surfactants, non-ionic, anionic, cationic and amphoteric 
surfactants can be used either singly or in combination as needed. Those 
obtained by adding ethylene oxide (for example, "X-77", trade name; or 
"Neugen EA80", trade name) or propylene oxide to alkylphenols, higher 
alcohols, alkylnaphthols, higher fatty acids, fatty acid esters and the 
like can be used as preferred non-ionic surfactants. Preferred exemplary 
anionic surfactants include the alkylsulfonate salts (e.g., "Neopelex", 
trade name), alkylsulfate ester salts, phosphate ester salts and the like 
of alkylphenols, alkylnaphthols, higher alcohols, higher fatty acids, 
fatty acid esters and the like. Lignin-sulfonate salts (e.g., "Sunekis", 
trademark) are also preferred examples. 
The content of each compound of formula (I) in the associated herbicidal 
composition according to the invention varies depending on the 
formulation. In general, it can be 0.05-20 wt.% in a powder, 1-50 wt.% in 
a wettable powder, 0.05-15 wt.% in a granule, 1-50 wt.% in an emulsion, 
1-50 wt.% in a flowable formulation and 1-50 wt.% in a dry flowable 
formulation. Preferably, it can be 0.5-5 wt.% in a powder, 10-40 wt.% in a 
wettable powder, 0.5-8 wt.% in a granule, 5-20 wt.% in an emulsion, 10-30 
wt.% in a flowable formulation and 10-40 wt.% in a dry flowable 
formulation. 
The total content of auxiliary agents may be 0-80 wt.%. The content of the 
carrier is the value which is obtained by subtracting the contents of the 
compound as an active ingredient and of auxiliary agents from 100 wt.%. 
The herbicidal compositions of the invention, which contain one or more of 
the compounds represented by the formula (I), may be formulated together 
with one or more other herbicides or with one or more of agricultural 
chemicals such as fungicides, insecticides and plant growth regulators, 
fertilizers and soil improving agents, to say nothing of combined use 
therewith. Synergistic effects may be expected in some instances. 
The term "other herbicides" as used herein can mean the following compounds 
as active ingredient, although not necessarily limited thereto: 
3,6-Dichloro-2-methoxybenzoic acid (dicamba) 
2,5-Dichloro-3-aminobenzoic acid (amiben) 
4-Chloro-2,2-dimethylvaleranilide (monalide) 
3,4-Dichloropropionanilide (propanil) 
3,4-Dichloro-2-methylacrylanilide (dicryl) 
3,4-Dichlorocyclopropanecarboxanilide (crypromid) 
3,4-Dichloro-2-methyl-pentananilide (karsil) 
N,N-Dimethyl-2,2-diphenylacetamide (diphenamide) 
N-naphthylphthalamic acid (naptalam) 
N-(1,1-Dimethylbenzyl)-2-bromo-tert-butylacetamide (buromobutide) 
2-Benzothiazol-2-yloxy-N-methylacetanilide (mefenasate) 
1,1-Dimethyl-3-phenylurea (fenuron) 
3-(4-Chlorophenyl)-1,1-dimethylurea (monuron) 
3-(4-Chlorophenyl)-1-methoxy-1-methylurea (monolinuron) 
1-(2-Methylcyclohexyl)-3-phenylurea (siduron) 
1,1-Dimethyl-3-(3-trifluoromethylphenyl)urea (fluometuron) 
3-(3,4-Dichlorophenyl)-1,1-dimethylurea (diuron) 
3-(3,4-Dichlorophenyl)-1-methoxy-1-methylurea (linuron) 
3-(3-Chloro-4-methylphenyl)-1,1-dimethylurea (chlortoluron) 
3-[3-(N-Tert-butylcarbamoyloxy)phenyl]-1,1-dimethylurea (karbutilate) 
1-(.alpha.,.alpha.-Dimethylbenzyl)-3-(4-methylphenyl)urea (dymron) 
3-(4-Isopropylphenyl)-1,1-dimethylurea (isoproturon) 
3-(2-Benzothiazolyl)-1,3-dimethylurea (methabenzthiazuron) 
3-(2-Benzothiazolyl)-1-methylurea (benzthiazuron) 
3-(Hexahydro-4,7-methanoindan-5-yl)-1,1-dimethylurea (noruron) 
3-[5-(1,1-Diemthylethyl)-1,3,4-thiadiazol-2-yl]-1,3-dimethylurea 
(tebuthiuron) 
3-(5-Tert-butylisooxazol-3-yl)-1,1-dimethylurea (isouron) 
2-Chloro-4,6-bis(ethylamino)-1,3,5-triazine (simazine) 
2-Chloro-4-ethylamino-6-isopropylamino-1,3,5-triazine (atrazine) 
2-Chloro-4,6-bis(isopropylamino)-1,3,5-triazine (propazine) 
2-(2-Chloro-4-ethylamino 1,3,5-triazin-6-yl-amino)-2-methylpropionitrile 
(cyanazine) 
2-Methoxy-4,6-bis(isopropylamino)-1,3,5-triazine (prometon) 
2-Methylthio-4,6-bis(ethylamino)-1,3,5-triazine (simetryne) 
2-Methylthio-4,6-bis(isopropylamino)-1,3,5triazine (prometryne) 
2-Methylthio-4-isopropylamino-6-methylamino-1,3,5-triazine (ametryne 
2-Methylthio-4-isopropylamino-6-methylamino-1,3,5-triazine (desmetryne) 
4-Amino-6-tert-butyl-3-methylthio-1,2,4-triazin-5(4H)-one (metribuzin) 
3-Cyclohexyl-6-dimethylamino-1-methyl-1,3,5-triazin-2,4-(1H,3H)-dione 
(hexazinone) 
2-Chloro-N-isopropylacetanilide (propachlor) 
N-Methoxymethymethyl-2',6'-diethyl-2-chloroacetanilide (alachlor) 
2-Chloro-2',6'-diethyl-N-(butoxymethyl)acetanilide (butachlor) 
2-Chloro-2'-ethyl-6'-methyl-N-(2-methoxy-1-methylethyl)acetanilide 
(metolachlor) 
N,N-Diallyl-2-chloroacetamide (allidochlor) 
2,6-Dinitro-N,N-dipropyl-4-trifluoromethylaniline (trifluralin) 
3,4-Dimethyl-2,6-dinitro-N-1-ethylpropylaniline (pendimethalin) 
2-Chloro-N-(4-methoxy-6-methyl-1,3,5-triazin-2-yl-aminocarbonyl)benzenesulf 
onamide (chlorosulfuron) 
Methyl 2-[3-(4-methoxy-6-methyl-1,3,5-triazin-2-yl)ureidosulfonyl]benzoate 
(metsulfurone-methyl) 
Methyl 2-[3-(4,6-dimethylpyrimidin-2-yl)ureidosulfonyl]benzoate 
(sulfometuron-methyl) 
Methyl 2-[3-(4,6-dimethoxypyrimidin-2-yl)ureidosulfonyl]benzoate 
(bensulfuron) 
Ethyl 2-[3-(4-chloro-6-methoxypyrimidin-2-yl)ureidosulfonyl]benzoate 
(chlorinuron) 
3-[(4-Methoxy-6-methyl-1,3,5-triazin-2-yl)ureidosulfonyl]-2-thiophenecarbox 
ylic acid (thiameturon) 
2-(4-Isopropyl-4-methyl-5-oxo-2-imidazolin-2-yl)-nicotinic acid 
isopropylamine salt (imazapyr) 
2-(4-Isopropyl-4-methyl-5-oxo-2-imidazolin-2-yl)-3-quinolic acid 
(imazaquin) 
2-(4-Isopropyl-4-methyl-5-oxo-2-imidazolin-2-yl)-5-ethyl-3-pyridinecarboxyl 
ic acid (imazethapyr) 
Methyl 2-(4-isopropyl-4-methyl-5-oxo-2-midazolin-2-yl)-3(4)-benzoate 
(imadazolinone) 
3-Isopropyl-1H-2,1,3-benzothiazin-4(3H)-one-2,2-dioxide (bentazon) 
5-Bromo-3-sec-butyl-6-methyluracil (bromacil) 
3,5-Dibromo-4-hydroxybenzonitrile (bromoxynil) 
4-Hydroxy-3,5-diiodobenzonitrile (ioxynil) 
N-(Phosphonomethyl)glycine (glyphosate)

Preparation of certain compounds according to the invention will next be 
described specifically by the following examples. 
REFERENTIAL EXAMPLE 1 
Synthesis of 2-(4,6-dimethoxypyrimidin-2-yloxy)-benzaldehyde (intermediate) 
After 2.2 g of salicylaldehyde were dissolved in 100 ml of 
dimethylformamide, 4.0 g of 60% sodium hydride were added little by 
little. The resulting mixture was stirred at room temperature for a while 
and, after foaming subsided, 17.5 g of 2-chloro-4,6-dimethoxypyridine were 
added, followed by heating to 100.degree. C. After the mixture was stirred 
for 3 hours at the same temperature, dimethylformamide was recovered under 
reduced pressure. The residue was isolated by column chromatography on a 
silica gel and then eluted with a 7:3 mixed solvent of n-hexane and ethyl 
acetate, whereby 14.8 g of the target compound, 
2-(4,6-dimethoxypyrimidine-2-yloxy)benzaldehyde, were obtained as crystals 
(m.p.: 96.degree.-98.degree. C.; yield: 56.9%). 
IR (KBr) cm.sup.-1 : 2720, 1710. 
NMR (400 MHz, CDC;.sub.3) .delta. from TMS: 3.80(6H,s), 5.81(1H,s), 
7.27(1H,m), 7.36(1H,m), 7.64(1H,m), 7.95(1H,m), 10.24(1H,s). 
EXAMPLE 1 
Synthesis of 2-(4,6-dimethoxypyrimidin-2-yloxy)benzaldehyde 
di-n-butylacetal (Compound No. 3) 
2-(4,6-Dimethoxypyrimidin-2-yloxy)benzaldehyde obtained in Referential 
Example 1 (1.5 g), n-butyl orthoformate (1.6 g) and ammonium chloride 
(0.03 g) were added to 40 ml of n-butyl alcohol, followed by stirring 
under reflux. Two hours later, the reaction was terminated. The reaction 
mixture was concentrated under reduced pressure. The residue was subjected 
to chromatography on a silica gel column and then eluated with a 7:3 mixed 
solvent of n-hexane and ethyl acetate to purify the same, whereby 1.6 g of 
the target compound, 2-(4,6-dimethoxypyrimidin-2-yloxy)benzaldehyde 
di-n-butylacetal, were obtained (yield: 71.1%). 
EXAMPLE 2 
Synthesis of 2-(4,6-dimethoxypyrimidin-2-yloxy)benzaldehyde d-n-hexylacetal 
(Compound No. 5) 
2-(4,6-Dimethoxypyrimidin-2-yloxy)benzaldehyde (1.5 g), n-hexyl 
orthoformate (2.7 g) and ammonium chloride (0.03 g) were added to 40 ml of 
n-hexyl alcohol, followed by stirring under reflux. Two hours later, the 
reaction was terminated. The reaction mixture was concentrated under 
reduced pressure. The residue was subjected to chromatography on a silica 
gel column and then eluated with a 7:3 mixed solvent of n-hexane and ethyl 
acetate to purify the same, whereby 1.7 g of the target compound, 
2-(4,6-dimethoxypyrimidin-2-yloxy)benzaldehyde di-n-hexylacetal, were 
obtained (yield: 66%). 
EXAMPLE 3 
Synthesis of 2-(4,6-dimethoxypyrimidin-2-yloxy)benzaldehyde 
di-n-octylacetal (Compound No. 7) 
To a mixed solvent of 40 ml of n-octanol and 15 ml of benzene, 1 g of 
salicylaldehyde was added. The mixture was poured into an eggplant-type 
flask equipped with a SHEALAM cap, followed by purging with nitrogen. 
After the addition of 0.04 g of dichlorotris(triphenylphosphine)ruthenium, 
the mixture was reacted under heating at 100.degree. C. for 20 hours. 
After the completion of the reaction, the reaction mixture was filtered 
and the filtrate was concentrated under reduced pressure. The residue thus 
obtained (0.9 g) was dissolved in 10 ml of DMF, followed by the addition 
of 0.5 g of 2-chloro-4,6-dimethoxypyrimidine and 0.2 g of potassium 
carbonate. The resulting mixture was reacted under heating at 110.degree. 
C. for 3 hours. After the completion of the reaction, the reaction mixture 
was poured into 100 ml of water, followed by extraction three times, with 
50 ml each of ethyl acetate. The organic layer was washed, dried and 
concentrated under reduced pressure. The residue was subjected to 
chromatography on a silica gel column and then eluated with a 7:3 mixed 
solvent of n-hexane and ethyl acetate to purify the same, whereby 0.7 g of 
the target compound, 2-(4,6-dimethoxypyrimidin-2-yloxy)benzaldehyde 
di-n-octylacetal, was obtained (yield 17%). 
REFERENTIAL EXAMPLE 2 
Synthesis of 2-(4,6-dimethoxypyrimidin-2-yloxy)benzaldehyde dimethylacetal 
(Comparative Compound C) 
A mixture consisting of 52.6 g of 
2-(4,6-dimethoxypyrimidin-2-yloxy)benzaldehyde, 42.9 g of methyl 
orthoformate, 0.48 g of ammonium chloride and 500 ml of methanol was 
reacted at the reflux point for 5 hours under stirring. After the reaction 
mixture was cooled to room temperature, the precipitate was filtered off. 
The filtrate was concentrated under reduced pressure. The residue was 
subjected to chromatography on a silica gel column and then eluated with a 
7:3 mixed solvent of n-hexane and ethyl acetate to purify the same, 
whereby 61.0 g of the target compound, 
2-(4,6-dimethoxypyrimidin-2-yloxy)benzaldehyde dimethylacetal, were 
obtained as an oil (yield: 98%). 
NMR (400 MHz, CDCl.sub.3) .delta. from TMS: 3.26(6H,s), 3.79(6H,s), 
5.64(1H,s), 5.76(1H,s), 7.13(1H,d,J=8. 1Hz), 7.23-7.27(1H,m), 
7.34-7.38(1H,m), 7.64-7.66(1H,dd,J=8.1&1.5Hz) 
REFERENTIAL EXAMPLE 3 
Synthesis of 2-(4,6-dimethoxypyrimidin-2-yloxy)benzaldehyde diethylacetal 
(Comparative Compound D) 
The target compound was synthesized as an oil in a similar manner to 
Referential Example 2 (yield: 90%). 
NMR (400 MHz, CDCl.sub.3) .delta. from TMS: 
1.11(6H,t,J=7.3Hz), 3.51(4H,q,J=7.3Hz), 3.79(6H,s), 5.72(1H,s), 5.74(1H,s), 
7.11(1H,d,J=8.1Hz), 7.22-7.26(1H,m), 7.32-7.36(1H,m), 7.67-7.69(1H,m) 
Certain compounds were prepared in accordance with the procedures of 
Examples 1-3. They are summarized in Table 1. 
TABLE 1 
______________________________________ 
Comp'd NMR (400MHz) Synthesis 
No. R form (CDCl.sub.3 :.delta. TMS) 
route 
______________________________________ 
n-C.sub.3 H.sub.7 
oil 0.85(6H, d, J=7.3Hz), 
d 
1.45-1.53(4H, m), 3.35- 
3.48(4H, m), 3.79(6H, s), 
5.73(1H, s), 5.74(1H, s), 
7.12(1H, d, J=8.1Hz), 
7.22-7.25(1H, m), 7.31- 
7.35(1H, m), 7.68-7.70 
(1H, dd, J=8.1 & 1.5Hz) 
2 
i-C.sub.3 H.sub.7 
oil 1.00(6H, d, J=5.9Hz), 
d 
1.17(6H, d, J=5.9Hz), 
3.84(6H, s), 4.12-4.18 
(2H, m), 5.49(1H, s), 
6.99(1H, s), 7.19-7.24 
(2H, m), 7.33-7.39(2H, m) 
3 
n-C.sub.4 H.sub.9 
oil 0.84-0.87(6H, t, J=7.3Hz), 
d 
1.24-1.34(4H, m), 1.41- 
1.51(4H, m), 3.37-3.52 
(4H, m), 3.79(6H, s), 
5.70(1H, s), 5.75(1H, s), 
7.11(1H, d, J=8.1Hz), 
7.22-7.27(1H, m), 7.31- 
7.35(1H, m), 7.66-7.68 
(1H, m) 
4 
n-C.sub.5 H.sub.11 
oil 0.83-0.87(6H, m), 1.21- 
d 
1.31(8H, m), 1.43-1.50 
(4H, m), 3.37-3.48(4H, m), 
3.79(6H, s), 5.71(1H, s), 
5.75(1H, s), 7.12(1H, d, 
J=8.0Hz), 7.24-7.26 
(1H, m), 7.31-7.34(1H, m), 
7.66-7.68(1H, m) 
5 n-C.sub.6 H.sub.13 
oil 0.84-0.89(6H, m), 1.03- 
d 
1.31(12H, m), 1.41-1.47 
(4H, m), 3.37-3.49(4H, m), 
3.78(6H, s), 5.71(1H, s), 
5.74(1H, s), 7.11-7.12 
(1H, m), 7.24-7.27(1H, m), 
7.31-7.34(1H, m), 7.66- 
7.68(1H, m) 
6 n-C.sub.7 H.sub.15 
oil 0.85-0.88(6H, m), 1.23- 
d 
1.31(16H, m), 1.44-1.53 
(4H, m), 3.39-3.48(4H, m), 
3.79(6H, s), 5.71(1H, s), 
5.74(1H, s), 7.12(1H, d, 
J=8.0Hz), 7.24-7.26 
(1H, m), 7.31-7.34(1H, m), 
7.66-7.68(1H, m) 
7 n-C.sub.8 H.sub.17 
oil 0.85-0.89(6H, m), 1.23- 
d 
1.30(20H, m), 1.42-1.47 
(4H, m), 3.37-3.48(4H, m), 
3.78(6H, s), 5.71(1H, s), 
5.74(1H, s), 7.12(1H, d, 
J=8.0Hz), 7.22-7.26, 
(1H, m), 7.31-7.34(1H, m), 
7.66-7.68(1H, m) 
______________________________________ 
Formulation examples and herbicidal activity tests of certain herbicidal 
compositions according to the invention will next be described. 
FORMULATION EXAMPLE 1 
Wettable powder 
A wettable powder was obtained by thoroughly grinding and mixing 20 parts 
by weight of Compound No. 1 of the invention, 2 parts by weight of 
"Neopelex" (trade mark, product of Kao Corporation; sodium dodecyl benzene 
sulfonate), 1 part by weight of "Neugen EA80" (trade name, product of 
Sanyo Chemical Industries, Ltd.; polyoxyethylene nonylphenyl ether), 5 
parts by weight of white carbon and 72 parts by weight of diatomaceous 
earth. 
FORMULATION EXAMPLE 2 
Wettable powder 
A wettable powder was obtained by thoroughly grinding and mixing 20 parts 
by weight of Compound No. 2 of the invention, 2 parts by weight of sodium 
alkylbenzenesulfonate, 1 part by weight of polyoxyethylene alkylphenyl 
ether and 77 parts by weight of "Zeaklite". 
FORMULATION EXAMPLE 3 
Wettable powder 
A wettable powder was obtained by thoroughly grinding and mixing in a 
Jet-O-Miser 50 parts by weight of Compound No. 3 of the invention, 5 parts 
by weight of white carbon, 6 parts by weight of ammonium polyoxyethylene 
alkylphenyl ether sulfate, 2 parts by weight of sodium ligninesulfonate 
and 37 parts by weight of diatomaceous earth. 
FORMULATION EXAMPLE 4 
Flowable formulation 
A flowable formulation was obtained by adding 76.7 parts by weight of water 
to the mixture of 20 parts by weight of Compound No. 5 of the invention, 
2 parts by weight of sodium ligninesulfonate, 0.3 part by weight of 
xanthan gum and 1 part by weight of polyoxyethylene alkylaryl ether, 
mixing them and then finely grinding the resultant mixture in a sand 
grinder. 
FORMULATION EXAMPLE 5 
Flowable Formulation 
A flowable formulation obtained by wet grinding and mixing 30 parts by 
weight of Compound No. 2 of the invention and a solution of 10 parts by 
weight of "Sun Ekisu P252" (trade name, product of Sanyo-Kokusaku Pulp 
Co., Ltd.; sodium ligninesulfonate) in 50 parts by weight of water, adding 
0.2 part by weight of "Deltop" (trade mark, product of Takeda Chemical 
Industries, Ltd.; organic iodine antiseptic) and a solution of 0.2 part by 
weight of "Kelzan S" (trade name, product of Kelco Corp.; xanthan gum) in 
9.6 parts by weight of water and then mixing the resultant mixture. 
FORMULATION EXAMPLE 6 
Powder 
A powder was obtained by thoroughly grinding and mixing 1 part by weight of 
Compound No. 1 of the invention, 0.5 part by weight of "Emulgen 910" 
(trade name, product of Kao Corporation; polyoxyethylene nonylphenyl 
ether) and 98.5 parts by weight of kaolin clay. 
FORMULATION EXAMPLE 7 
Powder 
A powder was obtained by grinding and mixing 3 parts by weight of Compound 
No. 4 of the invention, 3 parts by weight of sodium ligninesulfonate, 2 
parts by weight of polyoxyethylene alkylaryl ether and 92 parts by weight 
of clay. 
FORMULATION EXAMPLE 8 
Dry flowable formulation 
A dry flowable formulation was obtained by mixing 60 parts by weight of 
Compound No. 6 of the invention, 5 parts by weight of sodium 
alkylbenzenesulfonate, and 35 parts by weight of polypropylene glycol 
polyethylene glycol ether. 
FORMULATION EXAMPLE 9 
Granules 
One part by weight of Compound No. 3 of the invention, 2 parts by weight of 
"Neopelex" (trade mark; described above), 2 parts by weight of "Sun Ekisu 
P252" (trade name; described above), 70 parts by weight of bentonite and 
23 parts by weight of talc were thoroughly mixed. A suitable amount of 
water was added to the resultant mixture to wet the same, followed by 
extrusion of the mass through a small injection molding machine into 
pellets. After the pellets were dried at 30.degree.-60.degree. C. in air 
and then crushed into granules, the granules were classified by a sifting 
machine to collect granules of 0.3-2 mm. 
FORMULATION EXAMPLE 10 
Granules 
One part by weight of Compound No. 6 of the invention, which had been 
finely ground, 2 parts by weight of "Gosenol GL-05s" (trade name, product 
of The Nippon Synthetic Chemical Industry Co., Ltd.; PVA), 2 parts by 
weight of "Sun Ekisu P-252" (trade name; described above) and 95 parts by 
weight of clay were thoroughly mixed. A suitable amount of water was added 
to the resultant mixture to wet the same, followed by extrusion of the 
mass through a small injection molding machine into pellets. After the 
pellets were dried at 60.degree.-90.degree. C. in air and then crushed 
into granules, the granules wre classified by a sifting machien to collect 
granules of 0.3-1 mm. 
FORMULATION EXAMPLE 11 
Emulsion 
Ten parts by weight of Compound No. 2 of the invention, 10 parts by weight 
of "Sorpole 800A" (trade name, product of Toho Chemical Industries Co., 
Ltd.; a nonionic/anionic surfactant mixture) and 80 parts by weight of 
o-xylene were mixed into an emulsion. 
FORMULATION EXAMPLE 12 
Emulsion 
Ten parts by weight of Compound No. 3 of the invention, 10 parts by weight 
of "Sorpole 800A" (trade name; described above) and 80 parts by weight of 
o-xylene were mixed into an emulsion. 
Test 1 
ALS (Acetolactate Syntase) Inhibition Test 
To determine the selectivity in enzyme level between crops and weeds, an 
ALS inhibition test was conducted using pea as a typical broadleaf crop 
and barnyardgrass as a representative gramineous weeds. 
After seeds of pea and barnyardgrass were allowed to germinate at 
25.degree. C. for 8-14 days in a dark place, partially-purified 
suspensions (Suspensions A) of acetolactate syntase were separately 
obtained from the seedlings in accordance with the procedures described in 
the literature, Plant Physiology, 75, 827-831. In a test tube, 0.5 mg of 
one of test compounds was weighed, followed by the addition of 0.15 ml of 
a 20 mM K.sub.2 HPO.sub.4 solution and 0.25 ml of a reaction substrate 
medium which consisted of 40 mM of K.sub.2 HPO.sub.4, 40 mM of sodium 
pyruvate, 1 mM of TPP, 1 mM of MgCl.sub.2 and 20 .mu.M of FAD so that 0.4 
ml of a reaction solution (Solution B) was prepared. Added to 0.4 ml of 
Solution B was 0.1 ml of Suspension A. After the resultant mixture was 
shaken for 1 hour in a thermostat water bath controlled at 30.degree. C., 
50 .mu.l of 6N sulfuric acid were added to terminate the reaction. 
Next, the test tube with the reaction-terminated liquid mixture contained 
therein was transferred into a thermostat water bath controlled at 
60.degree. C. and was heated for 15 minutes. Thereafter, 0.5 ml of a 0.5% 
creatine solution and 0.5 ml of a 5% alkaline .alpha.-naphthol solution 
were added, and the resultant mixture was maintained at 60.degree. C. for 
15 minutes. As a result, the test solution developed a pink-to-red color. 
After the above operation, the absorbance of the test solution at 525 nm 
was measured by a spectrophotometer (Absorbance 1 of Test Compound). 
Further, the absorbance (Absorbance 2 of Blank) of a solution obtained by 
subjecting a portion of Solution B to the above procedures without 
addition of any test compound and the absorbance (Absorbance 3 of sulfuric 
acid) of another solution obtained by subjecting another portion of 
Solution B to the above procedures which using 50 .mu.l of 6N sulfuric 
acid as a test compound were also measured. Based on the respective 
measurement values, the enzymoreaction inhibition rate at 10,000 ppm (0.5 
.mu.g/0.5 ml) of each compound was determined in accordance with the 
below-described formula. The results are shown in Table 2. 
Incidentally, the following compounds were used as Comparative Compounds A 
and B (this also applies to Test 2 and Test 3). 
TABLE 2 
______________________________________ 
Enzymoreaction inhibition rate (%) 
Compound Barnyardgrass 
Pea 
______________________________________ 
Compound No. 1 100 0 
Compound No. 2 100 0 
Compound No. 3 100 0 
Compound No. 4 100 0 
Compound No. 5 100 0 
Compound No. 6 100 0 
Compound No. 7 100 0 
Comp. Comp'd A 73 72 
Comp. Comp'd B 98 92 
______________________________________ 
##STR4## 
##STR5## 
##STR6## 
The results of the test indicate that the compounds of the invention show 
strong inhibition in enzyme level against gramineous weeds such as 
barnyardgrass but show no inhibition to broadleaf crops such as pea, in 
other words, have distinct selectivity. 
Test 2 
Upland Soil Application Test 
Resin-made 1/1000-are pots were filled with the soil of an upland field. 
After they were fertilized, cotton and soybean were seeded and 3 cm soil 
covering was applied. In addition, amaranth, common lambs-quarters, 
barnyardgrass, green foxtail, large crabgrass and johnsongrass were seeded 
and 1 cm soil covering was applied. One day later, a wettable powder 
prepared from a predetermined amount of each test compound in a similar 
manner to the procedures described in Formulation Example 1 was diluted 
with water and then sprayed evenly at an application rate equal to 10 l 
per are onto the surface of the soil by means of a pressure-operated 
sprayer. The weeds and crops were allowed to grow in a green house and 
influence to them were observed on the 50th day after the spray. The 
results are shown in Table 3. The degree of damages of each test plant and 
the degree of injury to each crop were determined by measuring fresh 
weight in each group and indicated by % calculated according to the 
following formula. 
##EQU1## 
TABLE 3 
__________________________________________________________________________ 
Results of Upland Soil Treatment Test 
Herbicidal effects 
Application Barnyard- Crop injury 
rate of active 
Amaranth 
Common 
grass Foxtail 
Crabgrass Soybean 
Cotton 
ingredient 
(Amaranthus 
lamb- 
(Echinochloa 
(Setaria 
(Digitaria 
Johnson- 
(Glycine 
(Gossypium 
(g ai/a) 
viridis) 
quarters 
crusgalli) 
viridis) 
adscendens) 
grass 
max) indicum) 
__________________________________________________________________________ 
Comp'd. No. 
1 50 100 100 100 100 100 100 0 0 
2 50 80 85 80 85 80 100 0 0 
3 50 100 100 100 100 100 100 0 0 
4 50 100 100 100 100 100 100 0 0 
5 50 100 100 100 100 100 100 0 0 
6 50 95 90 95 100 85 100 0 0 
7 50 80 85 85 90 80 100 0 0 
Comp. Comp'd 
A 50 100 100 100 100 100 100 100 100 
B 50 80 85 100 100 100 100 100 100 
C 50 80 100 100 100 100 100 50 55 
D 50 100 100 100 100 85 100 40 45 
E 50 45 50 55 60 60 35 30 30 
__________________________________________________________________________ 
In Table 3 and Table 4 below, Compounds C, D and E indicate the following 
compounds, respectively. 
##STR7## 
The results of the present test indicate that the compounds of the 
invention represented by the formula (I) exhibit high herbicidal effects 
against some broadleaf weeds and gramineous weeds including johnsongrass 
in soil treatment and can be used extremely safely for crops such as 
soybean and cotton compared with comparative compounds. 
Test 3 
Upland Foliar Application Test 
Resin-made 1/1000-are pots were filled with the soil of an upland field. 
After they were fertilized, cotton and soybean were seeded and 3 cm soil 
covering was applied. Five days later, amaranth, common lambsquarters, 
barnyardgrass, green foxtail, large crabgrass and johnsongrass were seeded 
and 1 cm soil covering was applied. They were allowed to grow in a green 
house. When each plant grew to the stage of 2-3 leaves, an emulsion 
formulated from a predetermined amount of each test compound in a similar 
manner to the procedures described in Formulation Example 11 was diluted 
with water and then sprayed at a predetermined application rate by means 
of a pressure-operated sprayer. The application rate was controlled at 5 l 
per are. Influence to the crops and weeds were observed on the 40th day 
after the spray of the herbicides. The results are shown in Table 4 in 
which the degree of damages of each test plant and the degree of injury to 
each crop are shown in a similar manner to Test 2. 
TABLE 4 
__________________________________________________________________________ 
Results of Upland Foliar Application Test 
Herbicidal effects 
Application Barnyard- Crop injury 
rate of active 
Amaranth 
Common 
grass Foxtail 
Crabgrass Soybean 
Cotton 
ingredient 
(Amaranthus 
lamb- 
(Echinochloa 
(Setaria 
(Digitaria 
Johnson- 
(Glycine 
(Gossypium 
(g ai/a) 
viridis) 
quarters 
crusgalli) 
viridis) 
adscendens) 
grass 
max) indicum) 
__________________________________________________________________________ 
Comp'd. No. 
1 50 100 100 100 100 100 100 0 0 
2 50 100 80 80 100 85 100 0 0 
3 50 100 100 100 100 100 100 0 0 
4 50 100 100 100 100 100 100 0 0 
5 50 100 100 100 100 100 100 0 0 
6 50 95 90 95 95 90 100 0 0 
7 50 90 85 95 90 90 100 0 0 
Comp. Comp'd 
A 50 100 100 100 100 100 100 100 100 
B 50 80 80 100 100 100 100 100 100 
C 50 100 90 100 95 90 100 40 50 
D 50 100 90 100 95 90 100 35 35 
E 50 60 65 65 50 45 30 30 30 
__________________________________________________________________________ 
The results of the above test indicate that the compounds of the invention 
represented by the formula (I) exhibit high herbicidal effects against 
some broadleaf weeds and gramineous weeds including johnsongrass in 
foliage application and can be used extremely safely for crops such as 
soybean and cotton compared with the comparative compounds. 
Test 4 
Application Test on Johnsongrass Emerging from Rhizome 
Resin-made 1/1000-are pots were filled with the soil of an upland field. 
After they were fertilized, rhizome of johnsongrass were transplanted to 
the pots and 3 cm soil covering was applied. They were allowed to grow in 
a green house. When each johnsongrass grew to the stage of 4-5 leaves, an 
emulsion formulated from a predetermined amount of each test compound in a 
similar manner to the procedures described in Formulation Example 11 was 
diluted with water and then sprayed at a predetermined application rate by 
means of a pressure-operated sprayer. The application rate was controlled 
at 5 l per are. The effect of each compound against the johnsongrass 
emerging from its rhizome was observed on the 50th day after the spray of 
the herbicides. The results are shown in Table 5 in which the herbicidal 
effect against johnsongrass is shown in a similar manner to Test 2. 
TABLE 5 
______________________________________ 
Foliar Application to Johnsongrass 
Emerging from Rhizome 
Application 
Herbicidal effect 
rate of against johnson- 
active grass emerging 
Compound ingredient 
from rhizome 
______________________________________ 
Compound No. 1 
20 100 
Compound No. 2 
20 95 
Compound No. 3 
20 100 
Compound No. 4 
20 100 
Compound No. 5 
20 100 
Compound No. 6 
20 85 
Compound No. 7 
20 80 
Comp. Comp'd A 
20 60 
Comp. Comp'd B 
20 35 
Comp. Comp'd C 
20 40 
Comp. Comp'd D 
20 50 
Comp. Comp'd E 
20 5 
______________________________________ 
The results of the above test indicate that the compounds of the invention 
of the formula (1) exhibit the very high effect of controlling the 
johnsongrass emerging from rhizome. 
Generally, the johnsongrass emerging from rhizome grows rapidly and have 
many buds. Therefore, if the durability of the herbicidal effect is 
insufficient, the johnsongrass can easily restore or re-emerge by 
consuming the herbicidal effect. 
In contrast, since the compounds of the invention have the durable effect 
of inhibiting the growth of johnsongrass as shown in the results of the 
above test, they are very effective against the johnsongrass compared with 
the comparative compounds.