GB2124212A

GB2124212A - Fungicidal 1,2,4-thiadiazole derivatives

Info

Publication number: GB2124212A
Application number: GB08317065A
Authority: GB
Inventors: Kenji Hagiwara; Keiichi Ishimitsu; Shou Hashimoto; Susumu Shimoda
Original assignee: Nippon Soda Co Ltd
Current assignee: Nippon Soda Co Ltd
Priority date: 1982-06-24
Filing date: 1983-06-23
Publication date: 1984-02-15
Also published as: IT8348572A0; ES8500922A1; JPH038347B2; FR2529204A1; GB2124212B; FR2529204B1; CH654835A5; DE3322662A1; JPS58225077A; IL69021A0; ES523567A0; IL69021A; BE897119A; IT1174762B; HU193169B; GB8317065D0; KR840005119A; NL8302260A

Abstract

Novel 1,2,4-thiadiazole derivatives of the general formula <IMAGE> wherein R1 is an alkyl or allyl group; R2 is an alkyl, cycloalkyl, haloalkyl, di- alkylamino, di-alkylamino, benzyl, N- methylanilino, piperidino, alkoxy, alkylthio, alkylthio-alkylthio, alkenylthio, phenylalkylthio, furyl or thienyl group, or an unsubstituted phenyl or phenyl group substituted with one or two of halogen, methyl and nitro, X and Y are independently halogen, alkyl, haloalkyl, alkoxy, haloalkoxy, alkyl-thio, di-alkyl- amino, phenyl, or phenyl-amino, or a phenoxy group substituted with halogen, hydroxy or nitro, and m and n are independently 0, 1, 2 or 3, excluding the case where R1 is alkyl having 1 to 3 carbon atoms, R2 is unsubstituted phenyl and m and n are both zero, possess fungicidal properties.

Description

SPECIFICATION 1,2,4 -Thiadiazole derivatives The present invention relates to 1,2,4 - thiadiazole derivatives and to use thereof as a fungicide for agriculture and horticulture.

In the cultivation of agricultural and horticultural crops, a large number of preventive chemicals are used to exterminate crop diseases, but occasionally the preventivefungicidal effect is insufficientandthe use of a chemical agent is restricted by appearance of a new bacteria having resistance to the agent. In addition, the phytotoxicity or pollutant effect of an agent may occur on the plant body and its toxicity to humans, animals and fish may be too high. Thus, not all chemical agents can be used satisfactorily and there is always a need for an agent without such drawbacks and which can be used in safety.

According to the present invention there is provided a compound selected from the group consisting of 1,2,4 - thiadiazole derivatives ofthe general formula

wherein R1 is alkyl group having 1 to 6 carbon atoms or allyl group, R2 is alkyl group having 1 to 6 carbon atoms, cycloalkyl group having 3 to 6 carbon atoms, haloalkyl group having 1 to 4 carbon atoms, dialkylamino group having 2 to 8 carbon atoms, di-alkenylamino group having 4to 8 carbon atoms, benzyl group, N-methylanilino group, piperidino group, alkoxy group having 1 to 4 carbon atoms, alkylthio group having 1 to 4 carbon atoms, alkylthioalkylthio group having 2 to 8 carbon atoms, alkenylthio group having 2 to 4 carbon atoms, phenylalkythio group having 7 to 10 carbon atoms, furyl group, thienyl group, unsubstituted phenyl group or phenyl group substituted with one or two selected from a group consisting of halogen, methyl and nitro, X and Yare independently halogen, alkyl group having 1 to4carbon atoms, haloalkyl group having 1 to 4 carbon atoms, alkoxy group having 1 to 4carbon atoms, haloalkoxy group having 1 to 4 carbon atoms, alkyl-thio group having 1 to 4 carbon atoms, di-alkylamino group having 2 to 8 carbon atoms, phenyl group, phenyl-amino group, phenoxy group substituted with halogen, hydroxy group or nitro group, and m and n are independently 0,1,2 or3, excluding the case where R1 is alkyl group having 1 to 3carbon atoms, R2 is unsubstituted phenyl group and m and n are both zero.

Such a compound can be used as a fungicidal agent in agriculture and horticulture, with a preventive fungidical effect in a wide variety of plant diseases. In particular, it may be effective against phycomycetes such as downy mildew in cucumber and grape, pythium seedling blight, eggplant brown rot, apple scab, beet black rot and other bacterial plant diseases.

A synthetic process for production of a compound having the general formula (I) in which R1 is alkyl group having 1 to 3 carbon atoms, R2 is phenyl group and m and n are both zero is described in Berichte 1979, vol 112, P517, but itsfungicidal activity is entirely unknown.

For preparation of a compound embodying the present invention, a compound represented by a general formula:

can be reacted with bromine in an organic solvent to provide a cyclized product, whereby hydrobromic acid salt of 1,2,4 -thiadiazole derivatives can be produced. In above general formula (II), R1, R2, X, Y, m and n are as previously defined.

The organic solvent can be an inert solvent such as methylene dichloride, chloroform, ethyl acetate, dimethylformamide (DMF) orthe like.

The reaction is preferably carried out at OOC to 50"C, desirably at 0 Cto room temperature, from 0.5 to 3 hours.

If necessary, an acid binder, such as pyridine,triethylamine, sodium hydroxide or the like, can be added in equivalent amount to the compound of the general formula (II). If the reaction is carried out by adding acid binder of two equivalent amount to the compound offormula (ll),thefreebasecan be obtained in a single step. However, the isolation step and the purification procedureforthe desired compound (I) are difficult, so that a process of initially isolating the hydrobromic acid salt thereof is preferred.

Such a hydrobromicacid salt can be reacted with a base in an appropriate organic solvent thereby to obtain the free compound (I). The organic solvent can bean inert solvent such as chloroform, methylene dichloride or the like, and the base can be an inorganic or organic base, such as sodium hydroxide, pyridine,triethylamine orthe like.

The compound ofthe above-mentioned general formula (Il) can be produced by the reaction formula as exemplified below:

The Chemical formula(e) appearing in the printed specification were submitted after the date of filing, the formula(e) originally submitted being incapable of being satisfactorily reproduced.

If X is an electron-withdrawing radical such as nitro group, the reaction formula (2) is preferably used.

Methods for producing compounds embodying the present invention will now be more particularly described with reference to the following Examples.

Reference Example 1:

61.49. (0.4 mol) of N-methylbenzimidoyl chloride were dissolved in 360ml of acetone and 680ml of acetone containing 32.49 of sodiumthiocyanate were added dropwiseto the acetone solution with stirring at -30 to -20 C.

After the mixture had been stirred at -15 to -20 C for 10 minutes, 1 20ml of acetone solution containing 519 (0.4 mol) of 4 - chloroaniline were added in drops.

The reaction mixture was allowed to warm to room temperature and was stirred for a further two hours.

The precipitate obtained was filtered and washed with acetone and water, and 102.59 of 1-(4- chlor ophenyl) - 3 - (N - methylbenzimidoyl) thiourea were thus obtained.

Melting point: 167 to 1 68.5 C (yield: 84.4%) Example 1: (Compound No.6)

759 of 1 - (4- chlorophenyl) - 3 - (N - methylbenzimidoyl) thiourea obtained by Reference Example 1 were suspended in 640ml of methylene dichloride and 19.5g of pyridine.

The suspended solution was kept at 0 C to 5 C with stirring and simultaneously 39.59 of bromine in 90ml of methylene dichloride were added in drops.

Afterstirring for 30 minutes, the precipitate was filtered and the resulting crystals washed with methylene dichloride, ethanol and water in this sequenceandthen dried.

Thus, 759 of 5 - (4 - chlorophenylimino) - 2 - methyl 3 - phenyl - A3- 1,2,4 -thiadiazoline hydrobromic acid salt were obtained.

Yield: 79% Decomposition point (d.p.) : 224 to 225 C Example2: (Compound No. 5)

759 of 5 - (4 - chlorophenylimino) - 2 - methyl - 3 phenyl - - 1,2,4 -thiadiazoline hydrobromic acid saltweresuspended in 500ml of chloroform and30g oftriethylamine were added dropwisetothesuspen- sion with ice cooling.

The clear solution was washed with water, dried with anhydrous magnesium sulfate and was concentrated under reduced pressure until the crystalline started to separate.

n-Hexane was added to the resulting concentrated solution and thereby 529 ofthe desired material were obtained.

Yield: 88% Decomposition point (D.P.): 148 to 152"C Example 3: (Compound No. 43)

5.39. of 1 - (N - methyl -4-chlorobenzimidoyl) -3- (4 - n - propylphenyl) -thiourea were suspended in a mixture consisting of 30ml of methylene dichloride and 50ml of ethyl acetate, the suspension was stirred at 0 to 5 50C and simultaneously 2.459 of bromine in 5ml of ethyl acetate were added in drops.

After stirring at room temperaturefortwo hours, the crystalline was filtered and washed with acetone and thereby, 5.5g of 3 - (4 - chlorophenyl) - 2 - methyl 5- (4- n - propylphenylimino) -A3 - 1,2,4 - thiadiazoline hydrobromic acid salt were obtained.

Yield: 84% Decomposition point (D.P.): 205 to 2060C Example 4: (Compound No. 44)

4.29 of 3 - (4 - chlorophenyl) - 2 - methyl - 5 - (4 - n propylphenylimino) - A3 - 1,2,4 -thiadiazoline hydrobromic acid salt obtained in Example 3 were suspended in 20ml of chloroform, and triethylaminewas added dropwiseto the suspension until the crystalline was completely dissolved.

The clear solution was washed with water, dried with anhydrous magnesium sulfate and then concentrated under reduced pressure.

The residue was purified by column chromatography of silica gel and 3.09 ofthe desired material were obtained.

Yield: 88% Decomposition point (D.P.): 139 to 1 450C Example 5: (Compound No. 4)

4.39 of 1 - (4 - bromophenyl)-3-(N - methyl -2 thiophene-carboxyimidoyl) -thiourea weresus- pended in 30ml or methylene chloride and 60ml of ethyl acetate, the suspension was stirred at-5 to 0 C and simultaneously 1 .95g of bromine in 5ml of ethyl acetate were added in drops.

After stirring for 30 minutes, the separated crystalline was filtered and washed with ethyl acetate.

The crystals obtained were suspended in 50ml of chloroform and 150ml of 1 N aqueous solution of caustic soda were added to the suspension with ice cooling. The reaction mixture was stirred for 10 minutes.

The choloroform layer was washed with water, dried with anhydrous magnesium sulfate and then concentrated until the crystalline started to separate.

n-Hexane was added to the concentrated solution and the crystalline was sedimented, whereby 2.59 of the objective material were obtained.

Yield: 58% Decomposition point (D.P.): 142 to 145 C Example 6: (Compound No. 135)

39 of 1 - (3,4- dichlorophenyl) - ethyl - 5- methyl 4 - isodithiobiuretweresuspended in 50ml of methylene dichloride and 0.679 of pyridine, the suspension was stirred at 0 C and simultaneously 1.36g of bromine in 5m | of methylene chloride were added in drops.

Afterstirring for 30 minutes, the separated precipitate was filtered and the resulting crystals washed with methylene dichloride.

The crystals obtained were suspended in 50ml of chloroform and 150ml of 1 N aqueous solution of caustic soda were added to the resulting chloroform suspension with ice cooling. The reaction mixture was stirred for 10 minutes.

The clear chloroform layerwas washed with water and dried with anhydrous magnesium sulfate and 2.59 ofthe desired material were obtained after removal of the solvent under reduced pressure.

Yield: 77% Decomposition point (D.P.): 106 to 109 C In addition to the above-mentioned compounds, compounds embodying the present invention are listed in Table 1: Table 1

~ structural Formula 0 L' Z R2, N / Physical o 1 (51 N ~ Constant o R1-g~ S Sc f 1c d.p.

Ri Ri Xn and Tm Salt 1 CS, 4-Ct tl27n^130] 2 CH3 cs 4-Br - (128%131] 3 cli, 4-Ct E1351380 4 CH3 L 4-Br ~ [142145] 5 Cli, 4-CiS ~ p4B%152J 6 CH3 e 4-Ct HBr [224^2253 7 Cli Ct 4-Ct ~ [114X117] 8 CH3 C 4-Ct HBr f22(222J 9 Culls 4-Ct Scot Cll&commat;So,: [2322341

L01 ! cm. Cli, 4-Ct [145%14BJ 11' CH3 4-Ct [135X137] 12 ! CE3 < 4-Ct tl39xl44 1 13 Cli, 4-Br ~ tl34X136 ] 14 CH3 CHs 4-F E134'13B] 15 CH3 4-Br [142X145 ] 16 CH3 CHr3 4-CD - i132l351 17 Cl13 C 3-Ct [1531551 1B CH3 C 2-Ct 1141X146] 19 CH3 H 11 E145149J 20 CH3 CH2 2,3-Cz [159X162] 21 Cli3 2,4-Ct2 [135'b1381

22 CH, ( > 3.5-CJw2 - [1421451 23 CH3 &commat; 3-Br E138%1401 24 CH3 C 4-I --- [138N141] 25 CH3 C1 4-Ct ~ [151Y53] Ct 26 083 CH3 4-Ct BBr t226q.227] 27 CH3 ClX 4-CJC ~ t157%1591 28 CH3 A~ 3,4-Ct1 tl22124 ] ""(O) 29 CE 4ct E16'163.0 Ct 30 CH3 cos 4-Ct tlS6X161] 31 CH3 CW 4ct ~ tl676169 ] 32 CH3 CltW 4-Br - [164Ç165 33 Cis C 4-CE, - [1431145] CM

34 CH3 4-CH3 [116119] 35 CH3 Cl 4-CU3 [135%137] 3,4-(Cli,)2 36 Cli, at ~ [145521 37 CH3 &commat; D 2rb(CH3)2 nod51. 6345 38 CH3 C3 2,3-(CE3)2 [127~137] 39 CH3 C3 3,5-(CH1)2 --- [151X154] 40 CH3 Cte 2,4,6-(CH3) 3 ~ [162~165] 41 CH3 ce- 4-C2Hs HBr 223225] 42 CE, ClX 4-C2H5 - [144z149] 43 CE, Cl 4-C3H7 EBr [205X206] 44 CE, Ct 4-C3H7 [139X145] 45 CE, Ct 4-C3H7 HBr [2û1X203]

46 CE, Cl 4-.0,8,1 [148X150] 47 CH3 C 4-C*Hgn HBr [205] 46 CH3 C 4-C*Hsn HBr [133n 137 ] 49 CH3 4C4E,t [14744151] 50 CH3 CJC 4-OCE, --- [1442147] 51 CH3 e 4-OCHs [132%135] 52 CH3 /7 4-SCE, ~ [136X14û] 53 CH3 Ct 2-CE,, 4-Ct ~ [152X154] Ct Q 54 CH3 ( > 2-Br, 4-CR, ------ [159X161] 55 CH3 ~ 3-Ct, 4-CE, [126nP129] 56 CH3 CH2 3-CHI. 4-Br [135X142] 57 CR1 N02 4-C2 [16972]

58 CE3 < 4-No1 [i57uI59J 59 CH3 C3 4-Ct, SNOz f15415?] 80 CH3 A-H (CE,)2 [167171] 81 CH3 Cç 4-N(CH3) 2 HBr t2074210] 62 CH3 A 4-N(CH3) 2 . [152~155] 63 CH3 Cl 4-CF3 [141146] 84 CH3 &commat; 4-CF, [147~150] 65 C,Es &commat; 4-Ct HBr [19F1991 88 CzEs 4-02 ~~~~~~ r109,il71 67 C,Es 4-Ct tl37~142] ctTh 68 C1Ls Cte 3,5-012 1 97~120] 89 Cs 55 Cribs 4-Br ~ [117X33C]

70 C211s &commat; 4-CH3 HBr [19(rL192] 71 C2H, &commat; 4-CH3 nD5 51.6618 72 C2 H5 2,6 2,6-(CH3)2 ERr tl75%178] 73 C2Hs ( > 2,6-(CH3)2 --- nod1.6384 74 C2H5 &commat; 3H02 ~ DDs 51.6675 75 c387" ccl liBr 12 b2021 76 C,H7 D 4-Ct t 92~ 93] 77 C,H7 &commat; 4-CB3 ERr t19195] Go 78 C3H &commat; 4-CHs -- 18891] Go 79 C,H71 &commat; 4-Ct - t 48 511 Go 80 C*Hsn C2&commat; 4-Ct 1108~111] 81 411s C2 4-CE, RBr tl96sl97] ctTho

82 Ca,Hsn 4-CE, - [128X132 C11- 2-CsBs Ilasla691 83 CH3 Go 2-CsEs . t165X1691 84 CH3 Go 4-NH-CsEs 1139%1421 85 CH3 &commat; Go -ce tl31blU] 86 CH3 Go 4li 1188%192] 87 CH3 Go 4-OCF2Br - [123126] 88 CH3 CCt, 4-CI tl40 .142] 89 CH3 CH3 4-Ct (1O'il3] 90 CH3 Cilis 4-Ct t 72% 76] 91 CH3 CH(CH3)z 4-CJL BBr t202X206] 92 CH3 CH(CBa)2 4-Ct ~ tlloxll5] 93 CH3 -C(CH3) 3 4-Ct HBr [206G207

94 CH3 C(CH3)3 4-Ci - [107Ç110] 95 CH3 ,CH2 4-CI UBr [184X185] -CE CE2 96 CH3 -CHo CE2 4-CI [lColo6) -CE CE2 97 CH3 CH2 < 4-Ct HBr [209X211 ] CE2 98 CH3 CH24 4-Ct ~ [ 76 79] CE2 99 CH3 -NuCH3 4-Cl HBr [220X222] -H CE, 100 CH3 -NuCH3 4-Cl | [130X133] -E CE, 101 CH3 /CE3 4-Cl ; ECI [190qS192] -E Oo 102 CH3 -NoO 4-Cl n0271 6738 -E Qo 103 CH3 D 4-Cl i [126X129] 104 CH3 zCH2CH=CH2 4-Ct - g [ 60 63] CH2 CN=CH2 105 CH3 -OCH3 4-Cl i ----- [111n.114]

106 CH3 OC2Hs 4-Cl HBr [254%256] 107 CH3 OC2Es 4-Cl [ ôOx 84] 108 CH3 OC2H5 4-Br HBr [231X234] 109 CH3 0C28s 4-Br f 55s 58] 110 CH3 oC,Es 4-CE, - HBr [218~220] 111 CH3 oC,E, 4-CH3 [112%114] 112 CH3 SCE 4-Cl [117X120] 113 CH3 SC,lii 4-Ct --- - [124X126] 114 CE, SClizOO CH2 &commat; 4-Ct l [128qJ130 20 S16728 115 CHzCH=CHz BCE, 44 rLDo 116 i CH3 I BCE3 2,4-CE3 [126%1271 117 CH3 SC2H5 4-N02 -- [118120]

118 CH3 SC3H7n 4-Cl - [104~106] 119 CH3 SC4H9n 4-Cl - [ 87~ 90] 120 C2H5 SC2H5 4-Cl - n19D1.6625 121 CH3 SCH(CH3)2 4-Cl - [135~137] 122 CH3 SCH2CH=CH2 4-Cl - [ 86~ 89] 123 CH3 SC(CH3)3 4-Cl - [133~136] 124 CH3 SC2H5 4-Br - [135~138] 125 C2H5 SC2H5 4-Cl HBr [185~186] 126 CH3 SC2H5 4-CH3 HBr [185~187] 127 C2H5 SCH3 4-Cl HBr [181~184] 128 C2H5 SCH@ 4-Cl - n26D1.6663 129 CH3 SCH(CH3)C2H5 4-Cl - [100~102]

130 CH3 SCH(CHa)-Q 4-Ct ERr [180] 131 CH3 SCH(CE3)- 4-CJL ~ [128131] 132 CH3 sC2H45C2H5 4-CJL ERr tl85X187] 133 CH3 SC2HSC2B5 4-CJL -- t 44z 48] 134 CH3 SCHzSCH3 4-CJL tl06x108] 135 CH3 SC2Hs 3,4-Ct, tl06slog] 136 CH3 SC2Rs H RBr 1180%182] 137 CH3 SC2Hs | 3,5-Ct, no51.664 i3a1 cli, SC,Hs 2,4-Ct, I 2.4-Cllz 98%10o] 13 CH3 SC.H5 3,5-C4 i ERr [207X209] Compounds embodying the present invention may be used as the effective component of a fungicide either directly or in a form generally used for agricultural chemicals, for example a wettable powder, granules, a dust formulation, an emulsifiable concentrate, a soluble powder, a flowable formulation and an aersol. As a solid carrierthere can be used a vegetable powder such as soyabean powder and wheatflour, and a mineral fine powder such as diatomaceous earth, apatite, gypsum, talc, white carbon, pyrophyllite, bentonite and clay.As a liquid carriertherecan be used a solvent such as kerosene, mineral oil, petroleum, solvent naphtha, xylene, cyclohexane, cyclohexanone, dimethylformamide, dimethyl sulfoxide, alcohol, acetone and water. A surface active agent can, if necessary, be added in orderto give a homogeneous and stable formulation.

The concentration of the active ingredient in such a fungicidal composition may vary according to the type offormulation. The concentration is, for example, in the range of 5 to 80, preferably 30 to 60, weight percent for a wettable powder, 2 to 25, preferably 10 to 20, weight percent for an emulsifiableconcentrate, and 0.1 to 20, preferably 0.2 to 10, weight percentfora dust formulation.

The compound may be applied to plants in an amountof10g or more perlOare.

Wettable powders and emulsifiable concentrates can be diluted with water to specified concentrations and used as a suspension oran emulsion. Dusts and granules can be directly used for spraying on plants.

Some typical fungicidal composition are illustrated bythefollowing Examples: Example 7: Wettable powder tab 7 Compound No. 5 40 parts by weight Diatomaceous earth 53 Higher alcohol sulfate ester 4 alkylnapthalene sulfonate 3 The above components were homogeneously mixed and the resulting mixturewas finely crushed.

As a result, a wettable powder containing 40 percent of effective component was obtained.

Example 8: Emulsifiable concentrate tab2 Compound No.7 20 parts by weight Xylene 38 Dimethylformamide 35 Polyoxyethylene-alkylarylether 7 The above components were mixed with each otherand dissolved, andtherebyan emulsifiable concentrate containing 20 percent of effective componentwas obtained.

Example 9: Dustformulation tab 3 Compound No.33 10 parts by weight Talc 89 Polyoxyethylene-alkylarylether 1.0 The above components were homogeneously mixed and the resulting mixture was finely crushed.

As a result, a dust formulation containing 10 percent of the effective component was obtained.

However, compounds embodying the present invention can be used bythemselvesto obtain a satisfactory effect.

Such compound may have an insufficient or weak effect with respect to insect diseases other than those mentioned in the following Tests, andto compensate forthis the compounds can be used in mixture with one or more otherfungicides, insecticides and acaricides. Typical examples of fungicides, insecticides and acaricides which can be used in such a mixture are asfollows: Fungicides: captan, TMTD, zineb, maneb, mancozeb, TPN, allietts, prothiocarb,triadimefon,triadimenol, polyoxine,tridemorph, metaxanine, furalaxyl, triforine, isoprothiolane, probenazole, blasticidine-S, kasugamycin, validamycin, PCN B, iprodione, vinclozolin, procimidone, benomyl, thiophanate methyl, Basic copper chloride, Basic copper sulfate, fentin hydoxide, quinomethionate, propamocarband binapacryl.

Insecticides and acaricides: BCPE, chlorobenzilate, cholorpropilate, prochlonol, phenisorbromolate, dicofol, dinobuton, chlordimeform, amitraz, BPPS, PPPS, benzomate, cyhexatin, polynactins, thioquinox, CPCBS, tetradifon, tetrasul, cycloplate, phenproxide, kayahope, lime polysulfide, fenthion, phenitrothione, diazinon, chloropyrifos, ESP, vamidothion, phenthoate, dimethoate,formothion, malathion, trichlorfon,thiometon, phosmet, menazon, dichlorovos, acephate, EPBP, dialifor, methyl parathion, oxydemeton-methyl, ethion, aldicarb, propoxur, permethrin, cypermethrin, decamethrin, fenvalerate, fenpropathrin, pyrethrins, allethrin, tetramethrin, resmethrin, dimethrin, propathrin, prothrin, 3 - phenoxybenzyl - 2,2dichloro - 7 - (4-ethoxyphenyl) - t cyclopropanecarboxylate, (RS)- cx - cyano - 3- phenoxybenzyl - (RS) - 2 - (4 - trichloromethoxy- phenyl) -3 - methylbutyrate, (RS)- a - cyano - 3 phenoxybenzyl(RS) -2 - (2 - chloro - 4- trichlor- omethylanilino)- 3 - methylbutyrate and machine oil.

The fungicidal effect of compounds embodying the present invention are illustrated by the following tests: Testy Test for control of downy mildew (Pseudoperonospora cubensis) of cucumber.

A chemical solution having a specified concentration and obtained from a wettable powder including compound(s) embodying the present invention, was sprayed over cucumber seedlings (variety: "Sagami Hanjiro") in the course of about three weeks after planting.

After it had been air-dried, a liquid suspension of zoosporangia, which was collected from the morbid leaves suffering from downy mildew, was inoculated.

The inoculated cucumber seedlings were keptfor two days in an inoculating box at 25"C and 100% of relative humidity and then transferred to a greenhouse. In the course of 7th day after the inoculation, each leaf suffering from the disease was examined.

The disease-affected grade on the untreated comparison zone was set up as a standard and thereby its control value was calculated. The results are shown in Table 2. Phytotoxicity was not observed.

Table 2

Test Concentration (ppm) Control value Compound No. of active ingredient U) 1 400 92 3 400 93 4 400 98 5 400 100 6 400 I00 7 400 100 8 400 100 9 400 95 10 400 100 11 400 100 12 400 92 13 400 100 14 400 100 15 400 100 16 400 93 17 400 94 leo 400 94 19 400 93 20 400 94 21 400 96 22 400 94 23 400 100 24 400 93

25 400 100 27 400 93 28 400 94 30 400 96 33 400 100 35 400 100 36 400 100 37 400 100 38 400 94 39 400 100 40 400 93 41 400 94 42 400 100 43 400 96 44 400 96 45 400 90 46 400 90 47 400 96 48 400 100 49 400 93 50 400 94 53 400 94 54 400 94 55 400 90 56 400 90 57 400 94 60 400 90

63 400 90 64 400 96 65 400 100 66 400 100 67 400 90 68 400 100 69 400 90 70 400 95 71 400 90 72 400 92 73 400 94 74 400 95 75 400 95 76 400 94 77 400 94 78 400 89 80 400 92 82 400 92 83 400 91 84 400 91 85 400 94 86 400 91 87 400 93 88 400 93 89 400 93 94 400 93 95 400 97

96 400 90 98 400 97 99 400 97 100 400 97 101 400 97 102 400 90 103 400 93 109 400 97 111 400 97 112 400 90 114 400 100 118 400 97 119 400 93 120 400 93 121 400 90 122 400 93 128 400 94 129 400 97 130 400 97 131 400 93 132 400 90 137 400 90 138 400 100 140 * 400 98 Comparative** Agent 400 90

(163X165 C d.p.) ** commercial agent: terschloroisophtharonitrile wattable powder (75%) Test 2: Pot test for control of damping-off of cucumber seedling affected by Pythium aphanidermatum.

Five grains of cucumber seeds (variety: "Suyo") were sown in pots each having a diameter of 7cm .

Initially, the Pythium aphanidermatumwas cultured in a culture medium consisting of soil, bran and chaffandthen inoculated into pot soil.

The pot soil was covered with other soil and then irrigated with a chemical solution, having a specified concentration and prepared from a wettable powder incorporating a compound embodying the present invention. In the course of five days, the grade ofthe affected disease was investigated.

The disease-affected grade ofthe untreated com parison zone was defined asthestandard and thereby a control value calculated, the results being shown in Table 3. Phytotoxicity was not observed.

Table 3

Test Compound Concentration of Control No. Active Ingredient (ppm) value (Z) 25 400 78Z 27 400 90 36 400 100 40 400 100 49 400 90 52 400 85 65 400 85 70 400 100 72 400 100 73 400 98 Cenparison tqicidal 400 80 agent * *:Fungicidal agent sold in the market, "Tachigaren" i.e. a chemical solution containing 40 percent of3 hydroxy - 5 - methylisoxazole.

Test3: Test for control of apple scab (Venturia inaequalis).

Young apple seedlings (Variety: "Kogyoku") were cultivated in pots each having a diameter of 7.5cm.

When the seedlings had grown to the 3-4 leaves stage, a chemical solution, having a specified concentration and prepared from a wettable powder incorporating a compound embodying the present invention, was sprayed over the seedlings and the seedlingswere air-dried.

Conidia of Venturia inaequalis were inoculated onto the seedlings and they were initially kept in a humid chamber at 16"C, thereafter in a greenhouse at l5to200Cfortwo weeks.

The disease-affected grade was examined and the disease-affected grade in the untreated comparison zone was defined as a standard, whereby a disease control value was calculated. The results are shown in Table 4. Phytotoxicity was not observed.

Table 4

Test Compound Concentration of Control No. Active Ingredient (ppm) value (Z) 31 200 99 36 200 74 38 200 94 42 200 97 88 200 100 105 200 90 Comparison fungicidal 200 75 agent * *:Fungicidal agent sold in the market, "captan", i.e. a wettable powder containing 80 percent of N (trichloromethylthio) - 4 - cycohexene - 1,2 dicarboximide Test4: Test for control of cercospora leaf spot (disease affected by Cercospora beticola) of beet.

Young beet seedlings (Variety: "Monohiru")were cultivated in pots each having a diameter of 9cm.

Afterthe seedlings had grown to the 5-6 leaves stage, a chemical solution, having a specified concentration and prepared from a wettable powder including a compound embodying the present invention, was sprayed over the leaves, which were then air-dried.

Conidia of Cercospora beticola were atomized and inoculated onto the leaves, after which the seedlings were conserved in high humidity at 24to 260for one day and thereafter kept in a greenhouse at 23 to 280C for two weeks.

The disease spots generated were calculated and the disease-affected grade in the untreated comparison zone was defined asthe standard, whereby control values (%) in the chemical treated zone were calculated. The results are shown in Table 5. Phytotoxicity was not observed.

Table 5

Test Compound Concentration of Control value No. Active Ingredient (pupa) (Z) 1 400 84 31 400 79 49 400 90 52 400 65 112 400 100 113 400 92 115 400 90 119 400 94 120 400 94 121 400 100 122 400 97 134 400 92 138 400 95 139 400 94 Comparison fun- 400 70 gicidal agent * *:"Tin H" fungicide sold on the market, i.e. a wettable powder containing 17 percent offentin hydroxide.

Claims

1. A compound selected from the groupconsisting of 1 ,2,4-thiadiazole derivatives ofthe general formula

wherein R1 is alkyl group having 1 to 6 carbon atoms orallyl group, R2 isalkyl group having 1 to 6carbon atoms, cycloalkyl group having 3 to 6 carbon atoms, haloalkyl group having 1 to 4 carbon atoms, dialkylamino group having 2to 8carbon atoms, di-alkenlaminogroup having 4to 8carbon atoms, benzyl group, N-methylanilino group, piperidino group, alkoxy group having 1 to 4 carbon atoms, alkylthio group having 1 to4carbon atoms,alkylthioalkythio group having 2 to 8 carbon atoms, alkenylthio group having 2 to 4 carbon atoms, phenylalkylthio group having 7 to 10 carbon atoms, furyl group, thienyl group, unsubsituted phenyl group or phenyl group substituted with one or two selected from a group consisting of halogen, methyl and nitro, X and Y are independently halogen, alkyl group having 1 to 4carbon atoms, haloalkyl group having 1 to4carbon atoms, alkoxy group having 1 to 4 carbon atoms, haloalkoxygrouphaving 1 to4carbonatoms, alkyl-thio group having 1 to 4 carbon atoms, di-alkylamino group having 2 to 8 carbon atoms, phenyi group, phenyl-amino group, phenoxy group substituted with halogen, hydroxy group or nitro group, and m and n are independently 0, 1,2 or 3, excluding the case where R1 is alkyl group having 1 to 3 carbon atoms, R2 is unsubstituted phenyl group and m and n are both zero.

2. A compound as claimed in claim 1, wherein R1 is methyl or ethyl, R2 is unsubstituted phenyl, phenyl group substituted with one or two halogens, haloalkyl group having 1 to 4carbon atoms, alkylthio group having 1 to 3 carbon atoms or benzylthio group, is halogen, alkyl having 1 to 4 carbon atoms or hydroxy, andnisl,2or3.

3. Acompound substantially as hereinbefore described with reference to any one of compounds Nos. 1 to 139.

4. Asaltofa compound asclaimed in anyone of the preceding claims.

5. A method of preparing a compound as claimed in claim 1, the method being substantially as hereinbefore described with reference to any one of Examples 1 to 6.

6. Afungicidal composition comprising an inert carrier and a compound as claimed in any one of claims 1 to 3 or a salt as claimed in claim 4.

7. Afungicidal composition substantially as hereinbefore described with reference to any one of Examples 6 to 9.