Fungicides Captan

Tho garden fungicide Captan (2) is made from (1). This is an imide - a double atnide - and so both bonds between carbonyl and nitrogen can be disconnected,... 

The fungitoxic N-perhalogenmethylmercapto moiety was introduced for plant protection in 1950 The. two fungicides captan(l) (N-(trichloromethylthio)-tetrahydrophthalimide and folpet(2) (N-(trichlorome-thylthio)phthalimide) contain a perchlorinated methyl-thio group (1 ). About a decade later substitution of fluorine for one of the chlorines in the perchloro-... 

One important industrial application of the Diels-Alder reaction we have been discussing is in the synthesis of the agriculturl a fungicide Captan. 

An interesting feature of the numerical approach to structure-activity correlations has been pointed out (7) in the case of the phthalimide derivatives. The commercial fungicide Captan has the structure ... 

Carbon disulfide (1) may be chlorinated by the action of chlorine in the presence of iodine catalyst (Scheme 15). The reaction probably involves initial addition of chlorine to the C=S bond followed by loss of sulfur dichloride to yield trichloromethanesulfenyl chloride (34) (Scheme 15). Trichloromethanesulfenyl chloride (34) is a synthetic intermediate in the commercial manufacture of several valuable agricultural fungicides containing the NSCCI3 moiety (see Chapter 11, p. 235). An important example is the foliage fungicide captan (35), which is prepared from butadiene and maleic anhydride (36) via tetrahydrophthalimide (37)... 

Littlejohn, D., and Jamieson, N. (1995). Radiocesium in an organic soil and the effect of treatment with the fungicide Captan. Plant Soil 170, 315-322. 

Perchloromethyl mercaptan is an intermediate for making two important fungicides. Captan and Folpet. ... 

Salau, J. S., Alonso, R., Batllo, G., and Barcelo, D., Application of solid-phase disk extraction followed by gas and liquid-chromatography for the simultaneous determination of the fungicides — captan, captafol, carbendazim, chlorothalonil, ethirimol, folpet, metalaxyl, and vinclozolin in environmental waters. Anal. Chim. Acta, 293, 109-117, 1994. 

Most fungicides developed for plant disease control before 1965 are multisite biochemical inhibitors that lack the chemical properties and biological specificity required for internal therapeutic action in higher plants. This group of plant protectants include such compounds as the Inorganic copper fungicides, captan, chlorothalonil, dithiocarbamates and chlorinated quinones. 

Many analogs of nucleic and folic adds, which interfere with DNA synthesis, can be expected to cause chromosomal breaks. Similarly, breaks are caused by substances that alkylate DNA, such as bifunctional mitomycin C— which causes the formation of interstrand breaks—or the monofunctional streptronigrin, actinomydn, and neomycin— which form covalent bonds with DNA strands and intercalate between the strands (see Necrosis). Photodynamic dyes, like acridine or its derivative quinacrine, intercalate between DNA strands and in the presence of light and oxygen cause the strands to break. The fungicides Captan and maleic hydrazide (used to retard growth of ivy and grass) cause chromosomal breaks in vitro. 

Column chromatography has been widely used for the cleanup of samples, either individually or after preliminary purification by solvent partitioning. An example of the latter is the quantitative TLC determination of the fungicides captan, folpet, and captafol in lettuce and apples (79). Samples were extracted by blending with acetone and the extracts were filtered, pesticides were partitioned from the aqueous filtrate with petroleum ether-methylene chloride (1 1), the organic layer was concentrated and diluted with acetone and petroleum ether, and the solution was chromatographed on an activated Florisil column with elution by 200 ml of 15% ethyl ether in petroleum ether followed by 200 ml of 50% ethyl ether in petroleum ether. The eluates were concentrated and aliquots spotted for TLC analysis. 

Uses. The principal commercial appHcation for trichloromethanesulfenyl chloride is as an intermediate for the manufacture of fungicides, the most important being captan (A/-(trichlotomethylthio)-4-cyclohexene-l,2-dicatboximide) [133-06-2] (1) and folpet (/V-(tricblorometbyltbio)pbtba1 imide)... 

Several field experiments were conducted in Costa Rica from 1949 to 1952 by McLaughlin and Bowman (24), in which comparisons were made of Bordeaux mixture at 30- and 60-day intervals and Dithane Z-78 (zinc salt of ethylenebisdithiocar-bamic acid) and SR-406 [captan, n-(trichloromethylthio)-4-cyclohexene-l,2-dicarbox-imide] at 30-day intervals. Bordeaux mixture was found the most effective in reducing infection, but no significant differences were found in yield due to the treatments. Results of 1952 to 1953 experiments (37, 44) showed that Bordeaux mixture and Dithane Z-78 applied every 30 days increased yield in comparison with the other treatments. The yield increase obtained with Dithane might have been due to the presence of zinc in this fungicide and not to a reduction in the incidence of the disease. 

When the trouble is black thread, planters use paints, coal-tar washes, asphalt, and other treatments with varying degrees of success. New tests have shown that Fylomac 90, applied in a 0.25% solution, effects a cure in eight successive applications. In one of the most recent studies on this, Carpenter (8) tested 22 fungicides on Phytophthora panel trouble in Costa Rica. His work was under ideal conditions for the disease and with a well tested invariably successful, artificial method of inoculation. He found only one fungicide sufficiently good for his purpose—Ortho-cide 50 [captan, n-(trichloromethylthio)-4-cyclohexene-l,2-dicarboximide], wettable, mixed with Filmfast sticker. 

CASRN 133-06-2 molecular formula C9H8CI3NO2S3 FW 300.57 Biological. In water, captan reacted with the fungicide i-cysteine forming a compound with an absorption maximum of 272 mm which was identified as 2-thiazolidinethione-4-carboxylic acid. In addition, tetrahydrophthalimide also formed (Lukens and Sisler, 1958). 

Biological and Chemical Behavior of Perhalogen-methylmercapto Fungicides Metabolism and in Vitro Reactions of Dichlofluanid in Comparison with Captan... 

The sulfenyl phthalimides are one of the oldest groups of fungicides and are effective, safe and persistent (B-77MI10706). Captan (59) is cheaply made from the Diels-Alder adduct of butadiene and maleic anhydride, followed by conversion to the imide and reaction with trichloromethanesulfenyl chloride. Folpet (60) and captafol (61) are similar in structure. 

About 100 fungicides me required for these various uses in the United States. The principal ones are sulfur, liine-sulfur (polysulfides of calcium) copper sulfate (or ils equivalent in the oxides, basic sulfates, oxychloride and other relatively insnluhle copper compounds) creosote products and zinc chloride, both used as wood preservatives and a wide variety of organic compounds. Among the latter are several dithiocarbamates. such as ferbam and zineb, and other thio compounds, like N-(trichloronielhyllhio>-phthalimide (folpel) cis-NfI Irtchloroniclhy] Jthio)-4-cyclohexane- 1.2-dicaiboxyimide (captan) and 8-hydroxyquinoline. 

Heterocyclics. The heterocyclic compounds used as industrial antimicrobial agents are listed in Table 9. Captan and Folpet are agricultural fungicides that have found some industrial uses, primarily in solvent-based paints. Human toxicology concerns have resulted in some diminishing of markets (37). Lack of solubility has limited the formulation flexibility and product is typically available in a malleable concentrate (44—88%) (38). A typical synthesis has been disclosed (39). 

While the fungicides Folpet , Captan , and Captafol are forbidden in German vineyards, against B. cinerea, vinclozolin (Ronilan) 99, iprodione (Rovral) 100, and procymidone (Sumisclex) 101 are considered safe to use (89MI220) triadimefon (Bayleton) 102 is used against Oidium. 

Captan is a fungicide used to control fungal diseases of turf, fruit, and ornamental crops. 

The organic fungicides of the dithiocarbamate and phthalimide type (e.g. Captan) were a breakthrough in this field in the nineteen thirties and forties. Although they only have protective activity and thus must be used prophylactically, they found broad applications due to their high plant compatibility and broad disease control spectrum. 

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