Thiocarbamic acid derivatives

The preparation of alkali and ammonium salts of iV-substituted thiocarbamic acids is usually effected by addition of primary or secondary amines to carbonyl sulfide of carbon disulfide in the presence of ammonia or an alkali hydroxide. Using a strongly basic amine in place of the inorganic base affords the amine salt of the thiocarbamic acid 766,767 

Potassium A-phenyldithiocarbamate 773 An ethereal solution containing equimolar amounts of carbon disulfide and aniline is treated an with alcoholic solution containing an equivalent amount of potassium hydroxide. The colorless needles produced are readily soluble in water or alcohol but insoluble in ether. 

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Reaction wifli Salts and Esters of Thiocarbamic Acid 2-Hydroxythiazoles and Derivatives... 

Hydroxythiazoles give 2-chIorothiazole derivatives almost quantitatively upon treatment with phosphorus oxychloride (221, 229, 428). This constitutes a convenient synthesis method for these compounds when the conversion of 2-aminothiazoles to 2-chlorothiazole derivatives fails. Esters of thiocarbamic acid or thiourethanes also react with a-halocarbonyl compounds to give the corresponding 2-alkoxythiazoles (50, 68, 209, 272). 

The l3C chemical shifts of methyl derivatives with sulfur substituents [e.g., SH, -S, -SCH3, -SSCH3, -SSSCHj, -S(0)CH3, -S02CH3, -S(CH3)2+, -SC(0)CH3, -SC(S)CH3, and -SC(S)SCH3] (130,131) and of vicinal and gem-inal bis-sulfides (290) have been reported. Freeman and co-workers have published similar studies on thiols, sulfides, disulfides, and sulfinic and sulfonic acid derivatives (131,132,433) and Tseng and Bowler (434), on thiocarbamates, their S-oxides and S,5-dioxides [R-X-C(0)-NR 2 with X = S, SO, S02]. 

Janssen144-146 has successfully used a method resembling the co-technique (self-consistence within the HMO framework) to study the spectral properties of derivatives of thiocarbamic acid and thiourea these compounds lie outside the scope of this review, however. The possibility of using the HMO method to correlate excitation energies of the first (usually intense) bands of various classes of heterocyclic compounds has been investigated see, e.g., refs. 15,17, and 160. The... 

Carbamate pesticides are used as (1) insecticides, (2) fungicides and (3) herbicides. Insecticides are generally derived from carbamic acid fungicides, from thiocarbamic acid. The herbicide carbamates are a more complex class of compounds. Tables 21 and 22 list some commercial carbamate pesticides in approximate order of decreasing toxicity. It should be noted that the relative classification of highly and moderately toxic is no measure of the relative carcino-, muta- or teratogenicities of these carbamates, since it is based solely on acute LD q data (Morgan, ref. 20). 

Substituted thiazolidin-4-ones (449) are easily prepared by the reaction between chloracetic acid, or its derivatives (447), and a thiourea, a thiosemicarbazide, or a mono-or di-thiocarbamate (448 Scheme 255). The same a-chloro acid derivatives react with metallic thiocyanates yielding an intermediate (450), the cyclization of which gives a 2-iminothiazolidin-4-one (451). In these reactions a -chloracetic acid may be replaced by... 

Azine approach. Vicinal amino halides in which the halogen is in an activated azine position, e.g. (449), can form a thiocarbamic acid (77JHC1045), or an equivalent derivative, e.g. (450) (77JHC129). This intermediate subsequently undergoes cyclization by nucleophilic displacement of the halogen substituent. 

Coupling of a benzoic acid derivative under basic conditions is achieved with alkyl iodides," alkyl chlorides,dimethyl sulfate, or (l,1-dihydroperfluoroalkyl)phenyliodonium triflates. Common bases used arc potassium carbonate or sodium hydroxide (with phase-transfer catalyst). " Again, employing acid chlorides " - or anhydrides, " is the method of choice. The reaction can be performed without further activation, " " but in most cases the transformation takes place in the presence of the usual bases, triethylamine - " or pyridine " " " " " [in some cases 4-(dimethylamino)pyridine is added " ]. In a similar manner carbamates. thiocarbamates, " or thiocarbonates are synthesized. Perfluoropropcn-2-ol... 

TABtE 11-24 2-HYDROXYTHIAZOLE DERIVATIVES FROM o-HALO-CARBONYL COMPOUNDS AND SALTS AND ESTERS OF THIOCARBAMIC ACID (158a)... 

Replacement of halogen leads to formation of a C-S bond in many cases when alkyl or aryl halides are allowed to react with thiocarbonic acid derivatives such-as thiocarbamates, thiourea, dithiocarbamates, or xanthates. The importance of this method is due to the fact that the intermediates are readily converted into thiols by hydrolysis ... 

Aqueous photolysis of thiamethoxam 47 has been investigated (Seheme 17) <2000JFA4671>. The study showed that the by-products of the irradiation, on a 12 hours-on and 12 hours-off light cycle, are volatile products, which are trapped by cyclohexylamine. These fractions, trapped as thiocarbamate and isocyanic acid derivatives, have been... 

Reaction with salts and esters of thiocarbamic acid 2-hydroxy thiazoles and derivatives... 

More recently, organotin azides and tin derivatives of hydrazine, 1,3-diphenyltriazene, formamide, urea, isourea, guanidine, amidine, carbo-diimide, carbamic, and thiocarbamic acids, an imidoether and imido-phosphoranes have been prepared, so that now almost every imaginable type of organotin-nitrogen compound has become known. 

Derivatives of thiocarbamic acid are a family of very important fungicides used in many plant-care products. Manganese salts (maneb), zinc salts (zineb), sodium and iron salts have no action on aluminium, whatever their degree of dilution. On the other hand, copper salts of dithiocarbamic acid may attack aluminium. 

Cellulose reacts with isocyanates in anhydrous pyridine or with urea and substituted ureas at relatively high temperature to yield carbamates. The optimum carbamation reaction of microcrystalline cellulose with urea in a dry solid mixture has been studied [51]. In addition, a preferentially C6-modified cellulose carbamate derivative has been obtained [52]. Heating of cellulose with thiourea at 180°C yielded cellulose thiocarbamate [53]. Heat treatment of cellulose isocyanate products has been utilized for the production of urethanes [54]. When ceUuIose was treated with phenylisocyanate at 100 C in DMF in the presence of dibutyltin dilaurate and triethylenediamine, celiuiose bisphenylcarbamate was formed [55]. Treatment of cellulose with urea at temperatures at or above the latter s melting point (where urea decomposes into isocyanic acid and ammonia) has been employed for the production of cellulose carbamates fibers [56]. The advantages and disadvantages of using urea as an intermediate for production of fiber have been discussed [57]. 

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