Carbonyl sulfide, alkylation

Hydrobromic acid alkyl carbonate synthesis Carbonyl sulfide alkyl group source, long-chain Coconut acid alkyl halide mfg. 

Uses. There may be some captive use of carbonyl sulfide for production of certain thiocarbamate herbicides (qv). One patent (38) describes the reaction of diethylamine with carbonyl sulfide to form a thiocarbamate salt which is then alkylated with 4-chloroben2yl haUde to produce 3 -(4-chloroben2yl) A[,A/-diethylthiocarbamate [28249-77-6] ie, benthiocarb [28249-77-6]. Carbonyl sulfide is also reported to be useful for the preparation of abphatic polyureas. In these preparations, potassium thiocyanate and sulfuric acid are used to first generate carbonyl sulfide, COS, which then reacts with a diamine ... 

C-Carboxylation of enolates.1 Carboxylation of potassium enolates generated from silyl enol ethers is not regioselective because of extensive enolate equilibration. Regiospecific C-carboxylation of lithium enolates is possible with carbonyl sulfide in place of carbon dioxide. The product is isolated as the thiol methyl ester. If simple esters are desired, transesterification can be effected with Hg(OAc)2 (8, 444). Carboxylation of ketones in this way in the presence of NaH and DMSO is not satisfactory because of competing alkylation of the enolate.2 Example ... 

Only irreversible removal of the dithiol or of the solvolysis products can push the equilibrium to the right. Methods of choice are transacetalization to a highly reactive carbonyl derivative, alkylation to sulfide, oxidation of the thiol and formation of metal thiolates, for which mercury(II) salts are frequently used. 

The same alkyl thiocarbamates 95 can be prepared in 35-72% yield by reaction with disulfides and with carbon disulfide followed by alkylation with alkyl halides100. When carbonyl sulfide was used as electrophile, lithium /V,/V-dialkyldioxamates were formed, which after reaction with benzyl bromide gave thiooxamates 96 in 37-56% yield100. 

There are limited commercial uses of carbonyl sulfide. It is produced only in small quantities and used for small-scale experimental purposes and as a nonisolated, site-limited intermediate in the synthesis of organic sulfur compounds, thiocarbamate herbicides, and alkyl carbonates. Pesticide manufacturers... 

The radical carbonylation of alkyl and aryl radicals and the cyclization of the resulting acyl radicals onto tcrz-butyl sulfides leads to the formation of y-thiolac-tones with expulsion of the tert-butyl radical (Scheme 4-52) [89]. This process is applicable to a range of substituted 4-rerr-butylthiobutyl bromides and iodides giving moderate to excellent yields of the corresponding thiolactones. Using acyl selenide/tin hydride chemistry and competition kinetic methods, the rate constant for the cyclization was determined to be 7.5x10 s at 25 °C [89]. 

This reaction gives epoxides in good yield and returns the corresponding sulfide. In order to render this process catalytic in sulfide, it is necessary to find conditions for converting the sulfide back into the sulfur ylide in the presence of the carbonyl compound. Two procedures have been developed to achieve this (i) sulfide alkylation in the presence of base and (ii) reaction of a sulfide with a di-azo compound in the presence of a suitable metal catalyst. These methods are discussed in more detail in this chapter. 

Carbonyl sulfide (SCO) reacts with Grignard reagents at the carbonyl carbon [87], and this has been used to introduce a thiocarboxyl unit into organic molecules. For example, thiocarboxylations of enolates [88], phosphorous ylides [89], and an acyllithium [90] have been reported. Selenocarboxylation to organocopper reagents with carbonyl selenide (SeCO), followed by alkylation, gave selenol esters (Eq. 42) [91]. 

Carbonyl sulfide. See Carbonyl sulfide Carbopoi 613, 614, Carbopoi 615, 616, 617, Carbopoi 907. See Polyacrylic acid Carbopoi 910. See Carbomer 910 Carbopoi 934. See Carbomer 934 Carbopoi 934P. See Carbomer 934P Carbopoi 940. See Carbomer 940 Carbopoi 941. See Carbomer 941 Carbopoi 954. See Carbomer Carbopoi 971P. See Carbomer 941 Carbopoi 974P. See Carbomer 934P Carbopoi 980. See Carbomer 940 Carbopoi 981. See Carbomer 941 Carbopoi 1342, Carbopoi 1382. See Acrylates/C10-30 alkyl acrylate crosspolymer Carbopoi 1706, Carbopoi 1720. See Polyacrylic acid... 

The following metal compounds are used for the preparation of the catalysts oxides, metal carbonyls, halides, alkyl and allyl complexes, as well as molybdenum, tungsten, and rhenium sulfides. Oxides of iridium, osmium, ruthenium, rhodium, niobium, tantalum, lanthanum, tellurium, and tin are effective promoters, although their catalytic activity is considerably lower. Oxides of aluminum, silicon, titanium, manganese, zirconium as well as silicates and phosphates of these elements are utilized as supports. Also, mixtures of oxides are used. The best supports are those of alumina oxide and silica. 

This procedure can be regarded as conplementary to the thiolytic cleavage of the Dts imide protecting group. If, however, the reaction is carried out with triphenylphosphine at II0°C, under strictly anhydrous conditions, using toluene as solvent, the A-alkylated heterocycle is converted into the corresponding isocyanate 17 with concomitant formation of triphenylphosphine sulfide and carbonyl sulfide (eq 15) 4.. 13.14.24,27... 

The Sulfinol solvent consists of sulfolane (tetrahydrothiophene dioxide) and an alkanolamine, usually diisopropanolamine (DIPA) or methyldiethanolamine (MDEA), and water. The solvent with DIPA is referred to as Sulfinol-D or simply as Sulfinol, and the solvent with MDEA is referred to as Sulfinol-M. Typically, Sulfinol-D is used when essentially complete removal of both hydrogen sulfide and carbon dioxide and deep removal of carbonyl sulfide is desired. Sulllnol-M is used for the selective removal of hydrogen sulfide over carbon dioxide and the partial removal of carbonyl sulfide (Nasir, 1990). Both Sulfinol solvents are reported to be capable of removing mercaptans and alkyl sulfides to very low levels. 

Platinum and rhodium sulfided catalysts are very effective for reductive alkylation. They are more resistant to poisoning than are nonsulfided catalysts, have little tendency to reduce the carbonyl to an alcohol, and are effective for avoidance of dehydrohalogenation in reductive alkylation of chloronitroaromatics and chloroanilines (14,15). Sulfided catalysts are very much less active than nonsulfided and require, for economical use, elevated temperatures and pressures (300-2(KX) psig, 50-l80 C). Most industrial reductive alkylations, regardless of catalyst, are used at elevated temperatures and pressures to maximize space-time yields and for most economical use of catalysts. 

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