US 2913327 A
Description (OCR text may contain errors)
THIOLCARBAMATES AND USE AS HERBICIDES Harry Tilles, El Cerrito, and Joe Antognini, Mountain View, Calif., assiguors t Staulfer Chemical Company, a corporation of Delaware CERTAIN No Drawing. Application January 17, 1956 Serial No. 559,541
13 Claims. (Cl. 71-2.7)
Code Name Ethyl N N-di-n-propylthiolcarbamate. Methyl ,N-di-n-propylthiolcarbamate. n-Propyl ,N-di-n-propylthiolcarbamate. Ethyl N,N-pentamethylenethiolcarbamate. n-Propyl N,N-pentamethylenethiolcarbamate. Isobutyl N.N-di-n-propylthiolcarbamate. n-Butyl N,N-di-n-propylthiolcarbamate.
M N,N-di-n-butylthiolcarbamate. Ethyl N,N-di-n-butylthiolcarbamate. sec-Butyl N,N-di-n-propylthiolcarbamate. n-Amyl N, -di-n-propylthiolcarbamate. n-Propyl N ,N-di-isopropylthiolcarbamate.
Isopropyl N ,N-di-isobutylthiolcarbamate.
Thus, the compounds of the present invention may be represented by the formula:
wherein R is a lower alkyl radical and, R and R are lower alkyl groups which have at least three carbon atoms. R and R may be a single alkyl group having at least five carbon atoms and having two bonds available nited States Patent for attachment to the nitrogen atom, as in R-1817 wherev in N forms a part of a ring structure.
The following illustrative examples demonstrate the methods which may be employed to make typical compounds of the present invention. In the examples, all parts are by weight.
Example I (R-1608).Sodium is dispersed in xylene using oleic acid as the stabilizing agent until a particle size of 5-200 microns in diameter is obtained. Dispersion, equivalent to an amount of 16.9 parts (0.733 mole) of sodium, is then transferred to a reactor which has been previously flushed out with argon (or other inert gas such as nitrogen). A solution of 50 parts (0.806 mole) of ethanethiol dissolved in 86 parts of xylene is then gradually added to the sodium dispersion over an interval of 30 minutes. The temperature is maintained at 25 to 36 C. by cooling. The sodium ethylmercaptide forms as finely divided crystals which make an easily stirrable slurry. This suspension is heated to reflux, the heat is turned off, and parts (0.733 mole) of di-n-propylcarbarnyl chloride is added over an interval of 17 minutes to the refluxing slurry. The heat of reaction is sufficient to keep the xylene refluxing. After all of the di-mpropylcarbamyl chloride has been added, the mixture is refluxed for an additional 3 hours. It is then cooled, filtered from sodium chloride which has formed during the reaction, and the solvent is removed under reduced pressure. The residual liquid is then distilled under vacuum to give 125.5 parts (90.6% yield) of ethyl N,N-di-npropylthiolcarbamate (B.P. (31.5 mm.) 135.5 C.- 137.0 C., n 1.4770). The following analysis is obtained:
Calculated for Found CoHguN OS Percent C 57.1 67. 41 Percent H. 10.1 10. 26 Percent N- 7. 4 7. 17 16.9 16. 71 189 Example II (R-1607).When the general procedure of Example I is repeated except that 38 parts (0.50 mole) of l-propanethiol, sodium dispersion equivalent to 9.2 parts (.40 mole) of sodium, and 65.5 parts (0.40 mole) of di-n-propylcarbamyl chloride are employed, there is obtained 70.3 parts (86.5% yield) of n-propyl N,N-din- Example Ill (R1880).When the general procedure of Example I is repeated except that 9.12 parts (0.12 mole) of l-p-ropanethiol, sodium dispersion equivalent to 2.3 parts (0.10 mole) of sodium, and 19.2 parts (0.10 mole) of di-n-butylcarbamyl chloride are employed, there is obtained 20.4 parts (88.3% yield) of n-propyl N,N- di-n-butylthiolcarbamate, (B.P. (15 mm.) 156.5-159" C., n 1.4742
Example IV (R-1854).-When the general procedure of Example I is repeated except that 16.9 parts (0.188 mole) of Z-methyl-l-propanethiol, sodium dispersion equivalent to 3.45 parts (0.15 mole) of sodium and 24.5 parts (0.15 mole) of di-n-propylcarbamyl chloride are employed, there is obtained 25.2 parts (77.3% yield) of isobutyl N,N-di-n-propylthiolcarbamate (B.P. (18 mm.) 143145 0, n 1.4744).
Example V (RJ857).When the general procedure of Example I is repeated except that 16.9 parts (0.188 mole) of l-butanethiol, sodium dispersion equivalent to 3.45 parts (0.15 mole) sodium and 24.5 parts (0.15 mole) of di-n-propylcarbamyl chloride are employed, there is obtained 24.8 parts (76% yield) of n-butyl N,N-di-n-propyl- 3 thiolcarbamate (B.P. (19 mm.) l51.0-151.5' C., 11 1.4766).
Example VI (R-I866).The general procedure of Example I was followed except that 25 parts (0.52 mole) of methanethiol is added in small portions at 50-60 C. to the sodium dispersion equivalent to 2.3 parts (0.10 mole) of sodium. It is necessary to make sure that unreacted mercaptan does not build up in the reaction mixture since a violent reaction may take place if too much unreacted mercaptan is present with unreacted dispersion. After all of the sodium dispersion has reacted which is evidenced by the reaction mixture changing from a purplish hue to a white color, it is heated to reflux and 19.2 parts (0.10 mole) of di-n-butylcarbamyl chloride is added. After working up in the usual manner, there is obtained 13.9 parts (68.5% yield) of methyl N,N,-din-butylthiolcarbamate (B.P. (20 mm.) 144-146 C., n 1.4760).
Example VII (R-I870).The general procedure of Example I is followed except that 6.2 parts (0.10 mole) of ethanethiol is added to sodium dispersion equivalent to 2.3 parts (0.10 mole) of sodium at an initial tempera ture of 27 C. and allowing the temperature to rise to 65 C. during the mercaptan addition. The mixture is then heated to reflux and 19.2 parts (0.10 mole) of din-butylcarbamyl chloride is added. There is obtained 16.7 parts (76.8% yield of ethyl N,N-di-n-butylthiolcarbamate (B.P. (22 mm.) 154.0-154.5, r25 1.4740).
Example VIII (R-1606).273 parts of anhydrous isopropanol are added to a glass or steel reactor and 3.5 parts (0.153 mole) of sodium is added. The mixture is heated to reflux and the sodium gradually dissolves. The solution is then rapidly cooled in ice water. At 50 C., a thick solid of sodium isopropoxide comes out of solution. The mixture is cooled to 30 and then 9.17 parts (0.191 mole) of methanethiol is added rapidly. The solid dissolves immediately. The clear solution is heated to boiling and 198 parts of isopropanol is distilled off. 89 parts of anhydrous xylene is then added and 77 parts of isopropanol-xylene mixture is distilled. 89 parts more xylene is added and 89 parts of isopropanol-xylene mixture is distilled. 89 parts more xylene is added and 89 parts of solvent, probably pure xylene by now, is distilled. 49 parts more xylene is added, the mixture is heated to reflux, and 25 parts of di-n-propylcarbamyl chloride is added during 4 minutes. The reaction is not very exothermic. The mixture is then refluxed for 14 hours, cooled, filtered from salt, the cake is washed with a little xylene and the solvent is removed under reduced pressure. The residue is then vacuum. distilled and there is obtained 16.7 parts (62.5% yield) of methyl N,N-din-propylthiolcarbamate (B.P. (30 mm.) 1285-1295, a 1.4808).
Example IX (R-181 7 ).When the general procedure of Example VIII is repeated except that 11.7 parts (0.188 mole) of ethanethiol, 3.45 parts (0.15 mole) of sodium and 22.1 parts of N,N,-pentamethylenecarbamyl chloride are employed, there is obtained 14.4 parts (55.5% yield) of ethyl N,N-pentamethylenethiolcarbamate (B. P. (31.5 mm.) 1505-1510", 11 15168).
Example X (R-1905). When the general procedure of Example VIII is repeated except that 13.0 parts (0.125 mole) of l-pentanethiol, 2.3 parts (0.10 mole) of sodium and 16.4 parts of di-isopropylcarbamyl chloride are employed, there is obtained 15.8 parts (68.3%) of n-amyl N,N,-di-isopropylthiolcarbamate (B.P. (22 mm.) 145- 149 C., a 1.4721).
Example XI (R-1824).Wl1en the general procedure of Example VIII is repeated except that 14.3 parts (0.188 mole) of 2-propanethiol, 3.45 parts (0.15 mole) of sodium and 22.1 parts (0.15 mole) of N,N-pentarnethyl- The compounds of the present invention have been extensively tested as herbicides and have been particularly evaluated as pre-emergence herbicides. Pre-emergence herbicides are ordinarily used by placing a narrow band of the herbicide over the center of a seeded crop row at time of planting or before crop emerges. If the herbicide is harmless to the desired crop, seeds or seedlings, but phytotoxic to the weed seeds or seedlings most frequently encountered, the crop grows in an almost weedfree environment. Of course, the pre-emergence herbicide may be used over the entire field, but it is normally used in a narrow band which straddles the crop row and the balance of the weeds are controlled by various cultivation methods. The herbicides of the present invention are selective toward small seeded annual grasses and broad-leafed plants, and so are efiective against the most common weeds but have little effect on such valuable row crops as corn and beans. The phytocidal composition may be applied to the soil in any convenient form. For instance, it can be dissolved in a solvent, such as acetone, or emulsified and sprayed onto the soil, or it can be combined with a dry inert carrier and applied as a dust or as granules; although the composition may be applied to an entire crop plot, it is generally preferred to apply it in a narrow band, say 6", over the seeded row of a newly planted crop. Generally, rates of application of from one-half to twenty pounds per acre of actual area treated will be found suitable.
The following example shows the effect of R-1608 when used to protect corn from Weeds:
Example XlI.-A field test consisted of applying the compounds at the rate of 1, 2, 4, 8 and 10 pounds/80 gallons/acre as pre-emergence treatments to corn. The compound was dissolved in a small amount of acetone emulsified in water and applied at the desired rate by mounting a spray nozzle behind the planter packer wheel. A 6" band was applied and the rates of application are on the basis of the area of actual application and not on the total area of the plot treated. The weather was sunny, the air temperature 70 F., the soil temperature was 78, and the seed bed was in good tilth and very dry. Immediately after the test, the plots were sprinkler parison with check plots. The following data were obenecarbamyl. chloride are employed, there is obtained tained:
TABLE 1 Results 16 days after application Corn Stand 1 Rye 2 Rate I II III Av. I II III Av. A, lb.
1 10 8 l0 9. 3 100 100 100 100 2 9 15 8 10. 6 100 100 100 100 Rl608 4 11 10 12 11. 0 100 100 100 100 s 12 12 3 9. a 100 100 100 100 10 11 12 s 10. 3 100 100 100 100 Check.--- 0 9 6 11 8. 6 0 0 0 0 Oats 2 Dead Nettle 2 1 100 100 100 100 100 100 100 100 2 100 100 100 100 100 100 100 100 4 100 100 100 100 100 100 100 100 s 100 100 100 100 100 100 100 100 10 100 100 100 100 100 100 100 100 Check... 0 0 0 0 0 0 0 (l 0 1 Corn stand-number of plants/10 it. of row. 2 Percent control of weeds.
Example XIII.A number of the compounds were tested at rates of application of and 20 pounds per acre. The method of testing was to plant the seeds in 3" diameter paper cans and drench the material on at 30 ml can. The seeds tested were peas, corn, radish, cucumm2 81om1510010111 Oats Cucumber 4. As .a composition of matter, v n-propyl N,N-di-r1- propylthiolcarbamat'e.
5. As a composition of matter, n-propyl N,N-di-nbutylthiolcarbamate.
6. As a composition of matter, n-amyl, N,N-isopropylthiolcarbamate.
7. The method of combatting weeds comprising apply- Radish TABLE 2 The data set TABLE 3 Corn The seeds tested were peas,
sing app Rate/A.,
m N a O 5 a 000 5005000200 50000005000050000005050 79.005400835322002 o m mm m mmm mmm mmmm 11 11 55 T m w3118111 00111100000 1 65215560413033 W. n n u R 5 55 5 00500005000050.0000 M Ww%w%- m %%m% 7m3 2 05760581539298 11 111 1 1 5 5 5 5 8 00 O9 00 W w mm mmmw m mmmmlm N11 1 11 e m D. 000 00000000000 0000 .00 a 00 07 00 n e mmm mmmmwmmmmmwmmmi 1 11 S G 5 55 55 5 n 5 L 0 0 oooomom 08 00 h G mmm mmm mm1m1m 1 1 u S a U q 00000000000000000000 .00 00 e 0 -oO 00 S 6 mmmmmmmmwwmmmmmmmmlm l1 11 G 55 55 L 0 00 00 G mm mmm mmmmmmlm mm 11 11 n m C 00000000000000000000 00 00 I 0 00 90 9 mmmmmwmwmmmmmwmmmmlm l1 1 G 5 555 555 5 5 L 00om00000fi4 507 8 &5&95 86 66 G 11 1111 1 s a e P 5 a 00000000500500005000 07 00 57 00 G mmm mmmm mm mmmm mm m 11 2 2 2 2 2 2 n 2 a 0 oMoWeWoWoMowowowowowowmo mowowowmowo her and either rye or cats. The data set forth in Table 2 were obtained:
a e P 000000 102490 811 G 6 0 00000 M 828282 A W t m d "F" m "n" O p a 1 7 m 0 0 1 o MEN 0 a a a Example XIV.-A number of compounds were tested in flats in the greenhouse, at 2 /2 and pounds/ 80 gallons of solution/ acre. Application made with a fan type corn, squash, snapbeans, rye and oats. forth in Table 3 were obtained:
Compound nozzle at lbs. pressure.
Ge.=Percentage of seeds germinating. Gr.=Growth wherein 10 equals normal growth, and 0 indicates no growth.
We claim: 1. As a composition of matter, a compound of the formula R,s-GN
2. As a composition of matter ethyl N,N-di-n-propylthiolcarbamate.
3. As a composition of matter ethyl N,N-di-n-butylthiolcarbamate.
wherein R is a lower alkyl radical and R and R are identical lower alkyl radicals having at least three carbon 70 atoms. atoms.
ing to the soil :1 phytotoxic amount olf ethyl N,N-di-n- References Cited in the file of this patent propylthiolcarbamate. D T ES PAT NT 10. The method of combatting weeds comprising ap- UNITE S AT E S plying to the soil a phytotoxic amount of ethyl N,N-din- 2*060'733 Hunt et 1936 butynhiolcarbamate 2,160,880 Loane et a1. June 6, 1939 11. The method-of combatting weeds comprising ap- 2562911 fP July 1951 plying to the soil a phytotoxic amount of n-propyl N,N- 2642451 welllard et a1 June 1953 di n propylthiolcarbamate Kosmin g' 24! 12. The method of combatting weeds comprising applying to the soil a phytotoxic amount of n-propy1'N,N- 10 OTHER REFERENCES di-n-butylthiolcarbamate. Riemschneider et a1.: Monatshefte 84, pp. 5 18-21 13. The method of combatting weeds comprising ap- (1953).
plying to the soil a phytotoxic amount of n-amyl N,N-diisopropylthiolcarbamate.