Potassium dimethyl

Potassium dimethyl phosphorodithioate, see Malathion Potassium dimethyl phosphorothioate, see Malathion Prometone, see Propazine... 

We have found that the size of the gegenion is more important than the fact that it is nonmetallic. Potassium dimethyl malonate/18-crown-6 polymerizes MMA at 25-60 °C to give quantitative yields of PMMA, MWD 1.5-1.9. Excess malonate or methanol lowered the molecular weight of the PMMA but did not shut down the polymerization [67]. It is tempting to postulate that a hydrogen-bonded version of the Quirk intermediate (Scheme 13) is stabilizing enolate ends (Scheme 30). 

The proposed mechanism for this catalytic asymmetric hydrophosphonylation is shown in Figure 35. The first step of this reaction is the deprotonation of dimethyl phosphite by LPB to generate potassium dimethyl phosphite. This potassium phosphite immediately coordinates to a lanthanoid to give I due to the strong oxophilicity of lanthanoid metals. The complex I then reacts (in the stereochemistry-determining step) with an imine to give the potassium salt of the a-aminophosphonate. A proton-exchange reaction affords the product... 

Heterobimetallic catalysis mediated by LnMB complexes (Structures 2 and 22) represents the first highly efficient asymmetric catalytic approach to both a-hydro and c-amino phosphonates [112], The highly enantioselective hydrophosphonylation of aldehydes [170] and acyclic and cyclic imines [171] has been achieved. The proposed catalytic cycle for the hydrophosphonylation of acyclic imines is shown representatively in Scheme 10. Potassium dimethyl phosphite is initially generated by the deprotonation of dimethyl phosphite with LnPB and immediately coordinates to the rare earth metal center via the oxygen. This adduct then produces with the incoming imine an optically active potassium salt of the a-amino phosphonate, which leads via proton-exchange reaction to an a-amino phosphonate and LnPB. 

At the temperature of the hot tower, 40°C, potassium methylamide slowly decomposes into potassium dimethyl formamidide ... 

Aquatreat KM Carbamic acid, dimethyidithio-, potassium salt, hydrate Carbamodithioic acid, dimethyl-, potassium salt Casvrell No. 691 EINECS 204-875-1 EPA Pesticide Chemical Code 034803 Potassium dimethyl dithiocarbamate Potassium dimethyidithiocarbamate Potassium dimethylthio-carbamate. Polymerization short stops in the copolymerization of styrene and butadiene. Alco Chem. Corp. 

Derivatives of diazoethene have been invoked as highly unstable intermediates in a series of Wittig reactions. Gilbert s group added ketones to dimethyl diazomethyl-phosphonate (2.241) in the presence of potassium eA butoxide in THF at - 78 °C. In addition to potassium dimethyl phosphate and molecular nitrogen, dialkylated ethynes (2.246) were isolated. Scheme (2-95) shows the intermediates that are likely for this reaction C-Alkylation (2.242) is followed by the formation of a 1,2-oxaphosphetane (2.243). Elimination of dimethyl phosphate gives the diazoethene (2.244), from which N2 is eliminated to form the carbene 2.245. The alkyne is formed by the usual 1,2-shift of one of the alkyl groups. The carbene 2.245 can... 

Ethyl-potassium dimethyl-malonate gave tetra-methyl-succinic acid. 

In this way it was possible to isolate methyl-acrylic acid by the electrolysis of ethyl-potassium dimethyl-malonate, and ethyl-crotonic acid by electrolyzing a solution of the ethyl-potassium salt of diethyl-malonic acid. On the electrolysis of sebacic acid the ethyl ester of an unsaturated acid, CHj CH(CH,),.COOH, was formed. 

Di lve 20 g. of the cyano ester in 100 ml. of rectified spirit and add a solution of 19 2 g. of pure potassium cyanide in 40 ml. of water. Allow to stand for 48 hours, then distil oflF the alcohol on a water bath. Add a large excess of concentrated hydrochloric acid and heat under reflux for 3 hours. Dilute with water, saturate the solution with ammonium sulphate, and extract with four 75 ml. portions of ether. Dry the combined ethereal extracts with anhydrous sodium or magnesium sulphate, and distil off the ether. RecrystaUise the residual acid from excess concentrated hydrochloric acid, and dry in the air. The yield of pure ew-dimethyl-succinic acid, m.p. 141-142°, is 12 g. 

Dimethyl sulphate may be purified (a) by allowing it to stand over anhydrous potassium carbonate until it is neutral to Congo red paper, or (6) by washing, just before use, with an equal volume of ice water, followed by one-third of its volume of cold, saturated sodium bicarbonate solution. 

Mesityl oxide (Section 111,79) (I) condenses with ethyl malonate in the presence of sodium ethoxide to give the sodium derivative of (II) this upon hydrolysis with aqueous potassium hydroxide, followed by acidification, gives the cyclic diketone 5 5-dimethyl-l 3-cycfohexanedione (III), of which the enoUc form is 5 5-dimethyldihydroresorcinol (IV) ... 

A mixture of 0.10 mol of freshly distilled 3-methyl-3-chloro-l-butyne (see Chapter VIII-3, Exp. 5) and 170 ml of dry diethyl ether was cooled to -100°C and 0.10 mol of butyllithium in about 70 ml of hexane was added at this temperature in 10 min. Five minutes later 0.10 mol of dimethyl disulfide was introduced within 1 min with cooling betv/een -100 and -90°C. The cooling bath vjas subsequently removed and the temperature was allowed to rise. Above -25°C the clear light--brown solution became turbid and later a white precipitate was formed. When the temperature had reached lO C, the reaction mixture was hydrolyzed by addition of 200 ml of water. The organic layer and one ethereal extract were dried over potassium carbonate and subsequently concentrated in a water-pump vacuum (bath... 

A solution of 0.22 mol of butyllithium in 150 ml of hexane was cooled below -40°C and 140 ml of dry THF were added. Subsequently 0.20 mol of 1-dimethyl amino--4-methoxy-2-butyne (see Chapter V, Exp. 14) were added in 10 min with cooling between -35 and -45°C. After an additional 15 min 100 ml of an aqueous solution of 25 g of ammonium chloride were added with vigorous stirring. After separation of the layers four extractions with diethyl ether were carried out. The solutions were dried over potassium carbonate and then concentrated in a water-pump vacuum. Distillation of the residue gave a mixture of 8-10% of starting compound and 90-92% of the allenic ether, b.p. 50°C/12 mmHg, n 1.4648, in 82% yield (note 1). 

Similarly sodium methoxide (NaOCHj) is a suitable base and is used m methyl alco hoi Potassium hydroxide m ethyl alcohol is another base-solvent combination often employed m the dehydrohalogenation of alkyl halides Potassium tert butoxide [K0C(CH3)3] is the preferred base when the alkyl halide is primary it is used m either tert butyl alcohol or dimethyl sulfoxide as solvent... 

Compound A (C4H10) gives two different monochlondes on photochemical chlorination Treatment of either of these monochlondes with potassium tert butoxide in dimethyl sulfoxide gives the same alkene B (CaHg) as the only product What are the structures of compound A the two monochlondes and alkene B2... 

Compounds A and B are isomers of molecular formula C9Hi9Br Both yield the same alkene C as the exclusive product of elimination on being treated with potassium tert butoxide in dimethyl sulfoxide Hydrogenation of alkene C gives 2 3 3 4 tetramethylpentane What are the structures of compounds A and B and alkene C2... 

Double dehydrohalogenation to form terminal alkynes may also be carried out by heating geminal and vicinal dihalides with potassium tert butoxide m dimethyl sulfoxide... 

When 1 2 dibromodecane was treated with potassium hydroxide m aqueous ethanol it yielded a mixture of three isomenc compounds of molecular formula CioHi9Br Each of these compounds was converted to 1 decyne on reaction with sodium amide m dimethyl sulfoxide Men tify these three compounds... 

Potassium tert butoxide reacts with halobenzenes on heating in dimethyl sulfoxide to give ten butyl phenyl ether... 

The preparation of fluoroaromatics by the reaction of KF with perhaloaromatics, primarily hexachloroben2ene, has received considerable attention. Two methods were developed and include either the use of an aprotic, polar solvent, such as /V-methy1pyrro1idinone (8), or no solvent (9). These methods plus findings that various fluoroaryl derivatives are effective fungicides (10) prompted development of a commercial process for the production of polyfluoroben2enes (11). The process uses a mixture of sodium and potassium fluorides or potassium fluoride alone in aprotic, polar solvents such as dimethyl sulfoxide or sulfolane. 

A number of chemiluminescent reactions may proceed through unstable dioxetane intermediates (12,43). For example, the classical chemiluminescent reactions of lophine [484-47-9] (18), lucigenin [2315-97-7] (20), and transannular peroxide decomposition. Classical chemiluminescence from lophine (18), where R = CgH, is derived from its reaction with oxygen in aqueous alkaline dimethyl sulfoxide or by reaction with hydrogen peroxide and a cooxidant such as sodium hypochlorite or potassium ferricyanide (44). The hydroperoxide (19) has been isolated and independentiy emits light in basic ethanol (45). 

Oxidation. Nitroparaffins are resistant to oxidation. At ordinary temperatures, they are attacked only very slowly by strong oxidi2ing agents such as potassium permanganate, manganese dioxide, or lead peroxide. Nitronate salts, however, are oxidi2ed more easily. The salt of 2-nitropropane is converted to 2,3-dimethyl-2,3-dinitrobutane [3964-18-9], acetone, and nitrite ion by persulfates or electrolytic oxidation. With potassium permanganate, only acetone is recovered. 

Nitromethane also is used in the synthesis of the antiulcer dmg, ranitidine [66357-35-5]. A two-step process utilizing nitromethane, carbon disulfide, potassium hydroxide, and dimethyl sulfate yields l,l-bis(methylthio)-2-nitroethene [13623-94 ] which reacts further to produce ranitidine. 

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