IL44238A - Azetidine-1-carbothiolic(or dithionic)acid esters and their use as herbicides - Google Patents

Abstract

1453490 Herbicidal application of azetidine thiocarboxylic esters BASF AG 8 March 1974 [10 March 1973] 10418/74 Heading A5E [Also in Division C2] Herbicidal compositions comprise compounds of formula: where R<SP>1</SP> is alkyl, n is 0, 1, 2, 3 or 4, X is O or S and R<SP>2</SP> is an aliphatic radical optionally substituted one or more times by halogen, hydroxy, alkoxy or cyano or R<SP>2</SP> is where R<SP>1</SP> is halogen, nitro, cyano, alkoxy or alkyl, m 1 is 0, 1. or 2 and m 2 , is 0, 1, 2, 3 or 4 and, if m 2 or n is greater than 1, the substituents for R and/or R<SP>1</SP> may be identical or different. A list of other active ingredients is given. [GB1453490A]

Description

44238/2 »in»wni ο»¾ππ (n*jiK»n*f MI) n»'?i*n o»awy » t9 i a ona New azetidine-l-earbothiolic (or dithionie)ac.id eaters and their use as herbicides BASP AKTIENGBSELLSCHAFT C. 42416 4423-8/2 The present invention relates to new .and valuable .jj azetidine-l-carbothiolic (or dithionic). acid esters having a good herbicidal action, herbicides containing these compounds, and a process for controlling the growth of unwanted plants by using these compounds.

It is known from German Patent 1,300,947 to use S-ethyl-hexahydro-lH-azepine-l-carbothiolate for controlling unwanted plants in crops such as barley, wheat and rice. However, its action is poor.

We have now found that azetidine -1-carbothiolic (or dithionic) acid esters of the formula where R is alkyl (methyl, ethyl), n is 0,1,2,3 or 4, X 2 oxygen or sulfur, and R is an alkyl or. alkenyl radical, which may be substituted one or more times by halogen, 2 or R denotes a radical of the formula 44238/2 where R* denotes halogen (fluoro, chloro, bromo, iodo) , ^ ir^ denotes one of the integers 1 or 2 and m2 is one of the integers 0,1,2,3, and 4 and, if m2 is greater and 1, the substituents of R? may be identical or different, have a good herbicidal action. The compounds of the invention have the same herbicidal action as, and often a better action than, S-ethylhexahydro-lH-azepine-l-carbothiolate, combined with superior crop plant compatibility.

The active ingredients may be prepared by reacting a thiol chloroformate with an optionally substituted azetidine. The compounds may also be prepared by allowing azetldines in the form of the appropriate N-acyl chlorides to react with mercaptans.

The preparation .of the azetldines is well known from the literature.

EXAMPLE 1 S-ethyl- (2,2,4-trimethylazetidine)-l-carbothiolate At 50° to 40°C, 6.23 parts (by weight) of ethylthio chloroformate is dripped into a mixture of 4.95 parts of 2,2,4-trimethylazetidine and 6 parts of triethylamine in 50 parts of benzene.

After 1 hour the triethylamine hydrochloride is separated by suction filtration and the filtrate is washed with water. After drying, concentration is carried out in vacuo and the residue distilled off.

There is obtained 6.70 parts of S-ethyl (2, 2, -trimethyl-azetidine)-l-carbothiolate of the formula: O.Z. 29,752 Boiling point (0.1 mm Hg) : 59°C„ The following compounds may be prepared by the same process: S-methyl- (2, 2, 4-trimethylazetidine) -1-carbothiolate, b.p. (0.05 mm): 70°C S-propyl-(2,2,4-trimethylazetidine)-l-carbothiolate, b.p. (0.05 mm): 8l°C S-isopropyl- (2, 2,4-trlmethylazetidine)-l-carbothiolate, b.p. (0,01 mm): 67° to 71°C, S-sec-butyl-(2,2,4-trimethylazetidine)-l-carbothio'late, b.p. (0.01 mm): 75° to 80°C S-trichloroallyl-(2,2,4-trimethylazetidine)-l-carbothiolate, b.p. (0.01 mm): 130°C S-benzyl- (2, 2, 4-trimethylazetidine)- 1-carbothiolate, b.p. (0.01 mm) : 135°C S-(p-chlorobenzyl)-(2,2,4-trimethylazetidine)-l-carbothiolate, b.p. (0.05 mm): 154°C S-benzyl- (3, 3-dimethylazetidine) -1-carbothiolate, b.p. (0.01 mm) : 128°C S- (B-phenylethyl)- (2, 2, 4-trimethylazetidine)- 1-carbothiolate, b.p. (0.01 mm): 120° to 125°C, n2Q: 1. 398 S-(B-phenylethyl)- (3, 3-dimethylazetidine) -1-carbothiolate, b.p. (0.01 mm): 140° to 145°C, n2Q: I.5996 S-benzyl- (2, 2, 4-trimethylazetidine)-l-thlolcarbothiolate, b.p. (0.01 mm): 160°C, n^: 1.6026 O.Z. 29,752 S-propyl- (2, 2, -trimethylazetidine)-l-thiolcarbothiolate, b.p. (0.01 mm): 100°C, n^: 1.5540 S-benzylazetldine-l-carbothiolate, S-ethylazetldine-l-carbothiolate, S-propylazetidine-l-carbothiolate, S-isopropylazetidine-l-carbothiolate, S-benzyl- (2-methylazetidine)-l-carbothiolate, S- utyl- (2,2,4-trimethylazetidine)-l-carbothiolate, b.p. (0.01 mm): 90° to 95°C, n2Q: 1. 835.

Application may be effected for instance in the form of directly sprayable solutions, powders, suspensions, dispersions, emulsions, oil dispersions, pastes, dusts, or granules by spraying, atomizing, dusting, broadcasting or watering. The form of application depends entirely on the purpose for which the agents are being used; in any case it should ensure a fine distribution of the active ingredient.

For the preparation of solutions, emulsions, pastes and oil dispersions to be sprayed direct, mineral oil fractions of medium to high boiling point, such as kerosene or diesel oil, further coal-tar oils and oils of vegetable or mineral origin, aliphatic, cyclic or aromatic hydrocarbons such as benzene, toluene, xylene, paraffin, tetrahydronaphthalene, alkylated naphthalenes and their derivatives such as methanol, ethanol, propanol, butanol, chloroform, carbon tetrachloride, cyclo-hexanol, cyclohexanone, chlorobenzene, isophorone, etc., and strongly polar solvents such as dimethylformamide, dimethyl sulfoxide, N-methylpyrrolidone, water, etc. are suitable.

Aqueous formulations may be prepared from emulsion concentrates, pastes, oil dispersions or wettable powders by adding o.z. 29,752 water. To prepare emulsions, pastes and oil dispersions the ^ ingredients as such or dissolved in an oil or solvent may be homogenized in water by means of wetting or dispersing agents, adherents or emulsifiers. Concentrates which are suitable for dilution with water may be prepared from active Ingredient, wetting agent, adherent, emulsifying or dispersing agent and possibly solvent or oil.

Examples of surfactants are: alkali metal, alkaline earth metal and ammonium salts of ligninsulfonic acid, naphthalene- sulfonic acids, phenolsulfonic acids, alkylaryl sulfonates, alkyl sulfates, and alkyl sulfonates, alkali metal and alkaline earth metal salts of dibutylnaphthalenesulfonic acid, lauryl ether sulfate, fatty alcohol sulfates, alkali metal and alkaline earth metal salts of fatty acids, salts of sulfated hexadecanols, heptadecanols, and octadecanols, salts of sulfated fatty alcohol glycol ethers, condensation products of sulfonated naphthalene and naphthalene derivatives with formaldehyde, condensation products of naphthalene or naphthalenesulfonic acids with ■ , phenol and formaldehyde, polyoxyethylene octylphenol ethers, ethoxylated isooctylphenol, ethoxylated octylphenol and ethoxylated nony.lphenol, alkylphenol polyglycol ethers, tri- butylphenyl polyglycol ethers, alkylaryl polyether alcohols, isotridecyl alcohol, fatty alcohol ethylene oxide condensates, ethoxylated castor oil, polyoxyethylene alkyl ethers, ethoxylated polyoxypropylene, lauryl alcohol polyglycol ether acetal, sorbitol esters,, lignin, sulfite waste liquors and methyl cellulose.

Powders, dusts and broadcasting agents may be prepared by mixing or grinding the active ingredients with a solid o.z. 29,752 carrier.

Granules, e.g., coated, impregnated or homogeneous granules, may be prepared by bonding the active ingredients to solid carriers. Examples of solid carriers are mineral earths such as silica gel, silicic acid, silicates, talc, kaolin, Attaclay, limestone, lime, chalk, bole, loess, clay, dolomite, diatomaceous earth, calcium sulfate, magnesium sulfate, magnesium oxide, ground plastics, fertilizers such as ammonium sulfate, ammonium phosphate, ammonium nitrate, and ureas, and vegetable products such as grain flours, bark meal, wood meal, and nutshell meal, cellulosic powders, etc.

The formulations contain from 0.1 to 95, and preferably 0.5 to 90 by weight of active ingredient.

There may be added to the compositions or individual active ingredients (if desired, immediately before use) oils of various types, herbicides, fungicides, nematocides, insecticides, bactericides, trace elements, fertilizers, antifoams (e.g., silicones), growth regulators, antidotes and other herblcldally effective compounds such as substituted anilines, substituted aryloxycarboxylic acids and salts, esters and amides thereof, substituted ethers, substituted arsonic acids and their salts, esters and amides, substituted benzimidazoles, substituted benzoisothiazoles, substituted benzothiadiazinone dioxides, substituted benzoxazines, substituted benzoxazinones, substituted benzothiadiazoles, substituted biurets, substituted quinolines, substituted carbamates, substituted aliphatic carboxylic acids and their salts, esters and amides, substituted aromatic carboxylic acids and their salts, esters and amides, substituted carbamoylalkylthiol or -dithiophosphates, O.Z. 29,752 substituted quinazolines, substituted cycloalkylamldocarbo- --^ thlolic acids and their salts, esters and amides, substituted cycloalkylcarbonamidothiazoles, substituted dicarboxylic acids and their salts, esters and amides, substituted dihydrobenzo-furanyl sulfonates, substituted disulfides, substituted di-pyridylium salts, substituted dithiocarbamates, substituted dithiophosphoric acids and their salts, esters and amides, substituted ureas, substituted hexahydro-lH-carbothioates, substituted hydantoins, substituted hydrazides, substituted hydrazonium salts, substituted isooxazole pyrimidones, substituted Imidazoles, substituted isothiazole pyrimidones, substituted ketones, substituted naphthoquinones, substituted aliphatic nitriles, substituted aromatic nitriles, substituted oxadiazoles, substituted oxadiazinones, substituted oxadiazoli-dine diones, substituted oxadiazine diones, substituted phenols and their salts and esters, substituted phosphonic acids and their salts, esters and amides, substituted phosphonium chlorides, substituted phosphonalkylglyzines, substituted phosphites, substituted phosphoric acids and their salts, esters and amides, substituted piperidines, substituted pyrazoles, substituted pyrazole alkylcarboxylic acids and their salts, esters and amides, substituted pyrazolium salts, substituted pyrazolium alkyl sulfates, substituted pyridazines, substituted pyrldazones, substituted pyridine carboxylic acids and their salts, esters and amides, substituted pyridines, substituted pyridine carboxylates, substituted pyridinones, substituted pyrimidines, substituted pyrimidones, substituted pyrrolidine carboxylic acid and its salts, esters and amides, substituted pyrrolidines, o.z. 29,752 substituted pyrrolidones, substituted arylsulfonic acids and-^" their salts, esters and amides, substituted styrenes, substituted tetrahydrooxadiazine diones, substituted tetra-hydrooxadiazole diones, substituted tetrahydromethanoindendes, substituted tetrahydrooxadiazole thiones, substituted tetra-hydrothiadiazine thiones, substituted tetrahydrothiadiazole diones, substituted aromatic thiocarbonylamides, substituted aromatic thiocarbonylamides, substituted thiocarboxylic acids and their salts, esters and amides, substituted thiol carbama-tes, substituted thioureas, substituted thiophosphoric acids and their salts, esters and amides, substituted triazines, substituted triazoles, substituted uracils, and substituted uretldlne diones.

The last-mentioned herbicidal compounds may also be applied before or after the active ingredients or compositions thereof according to the invention.

These agents may be added to the herbicides according to the invention in a ratio by weight of from 1 : 10 to 10 : 1. The same applies to oils, fungicides, nematocldes, insecticides, bactericides, antidotes and growth regulators.

The agents according to the invention may be applied either once or several times before or after planting, before sowing, pre- or postemergence, or during emergence of the crop plants or weeds.

The amount applied may vary and depends in essence on the effect to be achieved. Rates are generally from 0.1 to 15 kg and more, preferably from 0.2 to 6 kg per hectare.

The new active ingredients have a strong herbicidal action and may be used as weedkillers or for controlling the growth o.z. 29,752 of unwanted plants. Whether the new active ingredients are used as total or selective agents depends in essence on the amount of ingredient used per unit area.

By "weeds" and "unwanted plant growth" we mean all mono cotyledonous and dicotyledonous plants which grow in loci where they are not desired. The agents according to the invention may therefore be used for controlling for instance Gramineae, such as Cynodon spp. Dactylis spp.

Digitaria spp. Avena spp.

Echinochloa spp. Bromus spp.

Setarla spp. Uniola spp.

Panicum spp. Poa spp.

Alopecurus spp. Leptochloa spp.

Lolium spp. Brachiaria spp.

Sorghum spp. Eleusine spp.

Agropyron spp. Cenchrus spp.

Phalaris spp. Eragrostis spp.

Apera spp. etc. j Cyperaceae, such as Carex spp. Eleocharis spp.

Cyperus spp. etc. ; Scirpus spp. dicotyledonous weeds, such Malvaceae, e.g.

Abutilon theoprasti Hibiscus spp.

Sida spp. etc. ; Malva spp.

O.Z. 29,752 Composltae, such as Ambrosia spp. Centaurea spp.

Lactuca spp. Tussilago spp.

Senecia spp. Lapsana communis Sonchus spp. Tagetes spp.

Xanthlum spp. Erigeron spp.

Iva spp. Anthemis spp.

Galinsoga spp. Matricaria spp.

Taraxacum spp. Artemisia spp.

Chrysanthemum spp. etc. ; Bidens spp.

Cirisum spp.

Convolvulaceae, such as Convolvulus spp. Cuscuta spp.

Ipomoea spp. etc.; Jaquemontla tamnifolia Cruciferae, such as Barbarea vulgaris Arabldopsls thaliana Brassica spp. Descuralnia spp.

Capsella spp. Draba spp.

Sisymbrium spp. Coronopus didymus Thlaspi spp. Lepidium spp.

Sinapis arvensis etc. ; Raphanus spp.

Geraniaceae, such as Erodium spp. etc. j Geranium spp.

Portulacaceae, such as Portulaca spp. etc. ; o.z. 29,752 Primulaceae, such as Anagallis arvensis etc.

Lysimachia spp.

Rubiaceae, such as Richardia spp. Diodia spp.

Galium spp. etc. ; Scrophulariaceae, such as Linaria spp. Digitalis spp, Veronica spp. etc. ; Solanaceae, such as Physalis spp. Nicandra spp.

Solanum spp. etc. j Datura spp.

Urticaceae, such as Urtica spp. etc. ; Violaceae, such as Viola spp. etc. ; Zygophyllaceae, such as Tribulus terrestis etc. ; Euphorbiaceae, such as Mercurialis annua Euphorbia spp Umbelliferae, such as Daucus carota Ammi majus Aethusa cynapium etc.; Commelinaeae, such as Commelina spp. etc. ; Lablatae, such as Lamlum spp.

Galeopsis spp.

O.Z. 29,752 ' *Leg minosaef such as edicago spp. Sesbanla exaltata Trifolium spp. Cassia spp.

Vicia spp. etc. ; Lathyrus spp.

Plantaginaceae, such as Plantago spp. etc. ; Polygonaceae, such as Polygonum spp. Fagopyrum spp.

Rumex spp. etc. j Aizoaceae, such as Mollugo vertlclllata etc. ; Amaranthaceae, such as Amaranthus spp. etc. ; Boraginaceae, such as Amsinckia spp. Anchusa spp.

Myostis spp. etc. ; Llthospermum spp.

Caryophyllaceae, such as Stellaria spp. Silene spp.

Spergula spp. Cerastlum spp.

Saponarla spp. Agrostemma githago Scleranthus annuus etc. j Chenopodiaceae, such as Chenopodlum spp. Atriplex spp.

Kochla spp. Monolepsis nuttaliana Salsola kali etc. ; Lythraceae, such as Cuphea spp. etc.; o.z. 29,752 Oxalidaceae, such as Oxalis spp. etc.; Ranunculaceae, such as Ranunculus spp. Adonis spp.

Delphinium spp. etc.; Papaveraceae, such as Papaver spp. etc.; Fumaria officinalis Onagraceae, such as Jussiaea spp. etc.; Rosaceae, such as Alchemillia spp. etc.; Potentilla spp.

Potamogetonaceae, such as Potamogeton spp. etc.; Najadaceae, such as Najas spp. etc.; Marsileaceae, such as Marsilea quadrifolia etc.

The new agents may be employed in cereal crops, such as Avena spp. Sorghum Triticum spp. Zea mays Hordeum spp. Panicum miliaceum Secale spp. Oryza spp. and in dicotyledon crops, such as Cruclferae, e.g.

Brassica spp. Raphanus spp.

Slnapis spp. Lepidium spp.

Compositae, e.g.

O.Z. 29,752 Lactuca spp. Carthamus spp.

Helianthus spp. Scorzonera spp.

Malvaceae, e.g.

Gossypium hirsutum Leguminosae, e.g.

Medicago spp. Phaseolus spp.

Trifolium spp. Arachis spp.

Pisum spp. Glycine max.

Chenopodiaceae, e.g.

Beta vulgaris Spinacla spp.

Solanaceae, e.g.

Solanum spp. Capsicum annuum Nico iania spp.

Linaceae, e.g.

Linum spp.

Umbelliferae, e.g.

Petrosellnum spp. Apium graveolens Daucus carota Rosaceae, e.g.

Fragaria Cucurbitaceae, e.g.

Cucumis spp. Cucurblta spp.

Lillaceae, e.g.

Allium spp.

Vitaceae, e.g.

Vitis finifera Bromeliaceae, e.g.

Ananas sativus. o.z. 29,752 EXAMPLE 2 In the greenhouse loamy sandy soil was filled into pots and sown with various seeds. The soil prepared in this manner was then immediately treated with 1 kg per hectare of active ingredients I, II, IV, V, VI and VII and, for comparison, with 1 kg per hectare prior art compound III, each compound being emulsified or dispersed in 500 liters of water per hectare.

During the experiment the plants were provided with large amounts of water. After weeks it was ascertained that active ingredients I, II, IV, V, VI and VII had hetter crop plant compatibility and a better herblcldal action than comparative compound III. o . z. 29, 752 The results of this experiment are given below.

Active ingredient I II III IV V VI vi: kg/ha 1 1 1 1 1 1 1 Crop plants: Brassica napus 0 0 10 0 0 0 0 Triticum aestivum 0 0 5 0 0 0 0 Unwanted plants: Echinochloa crus-galli 100 90 0 95 90 60 80 Lolium multiflorum 100 100 20 100 95 80 85 Lolium perenne 100 100 20 95 90 80 90 Avena fatua 60 80 0 60 55 40 70 Poa annua 100 100 50 100 85 85 100 Poa trivialis 100 100 30 95 85 85 95 0 = no damage 100 = complete destruction.

EXAMPLE 3 Various plants were treated at a growth height of from 3 to 15 cm with 1 kg per hectare of each of the active ingredients I, II, IV, V, VI and VII and, for comparison, with 1 kg per hectare of comparative compound III, each compound being dispersed or emulsified in 500 liters of water o . z. 29,752 per hectare.

During the experiment the plants were provided with large amounts of water. After weeks it was ascertained that active ingredients I, II, IV, V, VI and VII had better crop plant compatibility than prior art agent III, combined with the same good herbicidal action.

Active ingredient I II III IV V VI vi: kg/ha 1 1 1 1 1 1 1 Crop plants: Brassica napus 0 0 10 0 0 0 0 Triticum aestlvum 0 0 5 0 0 0 0 Unwanted plants: Echinochloa crus-galli 100 90 0 95 90 60 90 Lolium multiflorum 100 100 20 95 90 70 90 Lolium perenne 100 100 20 90 85 70 85 Avena fatua 60 80 0 50 o 50 Poa annua 100 100 30 95 90 70 90 Poa trivialis 100 100 30 90 90 65 85 0 = no damage 100 = complete destruction.

EXAMPLE 90 parts by weight of compound I is mixed with 10 parts by weight of N-methyl-a-pyrrolidone. A mixture is obtained which is suitable for application in the form of very fine drops.

EXAMPLE 20 parts by weight of compound II is dissolved in a mixture consisting of 80 parts by weight of xylene, 10 parts Ο.Ζ. 29, 752 by weight of the adduct of 8 to 10 moles of ethylene oxide d* 1 mole of oleic acid-N-monoethanolamide, 5 parts by weight of the calcium salt of dodecylbenzenesulfonic acid, and parts by weight of the adduct of 40 moles of ethylene oxide to 1 mole of castor oil. By pouring the solution into 100, 000 parts by weight of water and uniformly distributing it therein, an aqueous dispersion is obtained containing 0.02 by weight of the active ingredient.

EXAMPLE 6 20 parts by weight of compound I is dissolved in a mixture consisting of 40 parts by weight of cyclohexanone, 30 parts by weight of isobutanol, 20 parts by weight of the adduct of 7 moles of ethylene oxide to 1 mole of Isooctylphenol, and 10 parts by weight of the adduct of 40 moles of ethylene oxide to 1 mole of castor oil. By pouring the solution into 100, 000 parts by weight of water and uniformly distributing it therein, an aqueous dispersion is obtained containing 0.02$ by weight of the active ingredient.

EXAMPLE 7 20 parts by weight of compound II is dissolved in a mixture consisting of 25 parts by weight of cyclohexanol, 6 parts by weight of a mineral oil fraction having a boiling point between 210° and 280°C, and 10 parts by weight of the adduct of 40 moles of ethylene oxide to 1 mole of castor oil. By pouring the solution into 100, 000 parts by weight of water and uniformly distributing it therein, an aqueous dispersion is obtained containing 0.02$ by weight of the active ingredient.

EXAMPLE 8 20 parts by weight of compound I is well mixed with 3 parts by weight of the sodium salt of diisobutylnaphthalene- - 8 - o . z. 29, 752 s-sulfonic acid, 17 parts by weight of the sodium salt of a ligninsulfonic acid obtained from a sulfite waste liquor, and βθ parts by weight of powdered silica gel, and triturated in a hammer mill. By uniformly distributing the mixture in 20, 000 parts by weight of water, a spray liquid is obtained containing 0.1$ by weight of the active ingredient.

EXAMPLE 9 j5 parts by weight of compound II is intimately mixed with 97 parts by weight of particulate kaolin. A dust is obtained containing yfo by weight of the active ingredient.

EXAMPLE 10 30 parts by weight of compound I is intimately mixed with a mixture consisting of 92 parts by weight of powdered silica gel and 8 parts by weight of paraffin oil which has been sprayed onto the surface of this silica gel. A formulation of the active Ingredient is obtained having good adherence. 44238/2

Claims (17)

1. Azetidine-l-carbothiolic (or dithionic) acid esters of the formula 1 where R is alkyl, n is 0,1,2,3 or 4, X is oxygen or sulfur and 2 R is an alkyl or alkenyl radical which may be substituted 2 one or more times by halogen, or R is a radical of the formula where R' is halogen, m^ is 1 or 2 and m2 is one of the integers 0,1,2,3 and 4 and, if m2 is greater than 1, the substituents of R' may be identical or different.

2. S- (p-chlorobenzyl)-(2, 2, 4-trimethylazetidine)-l-carbo- thiolate.

3. S-benzyl- (2,2,4-trimethylazetidine)-l-carbothiolate.

4. S-methyl- (2,2,4-trimethylazetidine)-l-carbothiolate.

5. S-sec- utyl- (2,2,4-trimethylazetidine)-l-carbothiolate.

6. · S-isopropyl- (2, 2,4-trimethylazetidine) -1-carbothiolate.

7. S-trichloroallyl- (2,2,4- rimethylazetidine) -1-carbothiolate.

8. S-n-propyl-(2,2,4-trimethylazetidine)-l-carbothiolate.

9. S-benzyl- (3,3-dimethylazetidine)-l-carbothiolate.

10. S-(B-phenylethyl)-(2,2,4-trimethylazetidine)-l-carbo- thiolate.

11. S-ethyl-(2,2,4-trimethylazetidine)-l-carbothiolate.

12. S-benzyl- (2,2, -trimet ylazetidine) -1-thiocarbo-thiolate. _

13. S-propyl- (2, 2, -trimethylazetidine)-l-thiocarbo-thiolate.

14. s-(B-phenylethyl)-(3,3-dimethylazetidine)-l-carbo-

15. Compounds of formula i in Claim 1, substantially as described herein with reference to the Examples.

16. A herbidical composition comprising a compound of the formula I in Claim 1 alone or in admixture with a solid or liquid carrier.

17. A process for controlling the growth of unwanted plants wherein the soil or" the plants are treated with a compound of the formula I in Claim 1 or with a composition containing such compound and a solid or liquid carrier.