Potassium methoxide

Solution A was prepared by dissolving potassium acetate in methanol Solution B was pre pared by adding potassium methoxide to acetic acid Reaction of methyl iodide either with solu tion A or with solution B gave the same major product Why" What was this product" ... 

Potassium Methylate. Potassium methoxide [865-33-8] KOCH, mol wt 70.13, is a fine, free-flowing, yellowish-white, caustic, hygroscopic powder purity 96.5—99% powder density after loose shaking, 0.75 g/mL apparent density (packing weight), 1.00 g/mL medium grain size, 0.05 —0.8 mm easily soluble in alcohols (33% in methanol at 20°C), insoluble in hydrocarbons. 

The 2-alkyl group of 2-alkylisoxazolium salts is also susceptible to a -deprotonation. For example, treatment of 3,5-distyrylisoxazolium salt (199) with potassium methoxide followed by acid hydrolysis gave the natural /3-diketone curcumine (77H(7)24l). 

The oxaziridine ring itself is stable towards alkali there is, for instance, no substitutive ring opening by hydroxyl ions as in oxiranes. 2-r-Butyl-3-phenyloxaziridine (56) is not attacked by methoxide ion in methanol during 12 h at room temperature 3-isopropyl-2-r-octyloxaziridine does not react at room temperature with either solid potassium hydroxide or potassium methoxide solution (57JA5739). 

Trinitrobenzene reacts with dry acetone in the presence of potassium methoxide to give a crystalline violet compound CgHsN OjK. Deduce its identity from the C NMR spectra 18. Conditions ( 03)280, 25 °C, 22.63 MHz. (a) //broadband decoupled spectrum (b) without decoupling (c) expanded section of (b). 

Potassium methoxide, KOCH3, contains both covalent and ionic bonds. Which do you think is which ... 

Generally, both sodium methoxide and ethoxide are employed as basic catalysts, but sometimes potassium methoxide or sodium hydride67 is used. The alkali salts of the dicarboxylic acids are primarily formed, due to the basic reaction conditions, but after acidic workup the free acids are obtained in 20-60 % yield. Reesterification65 of the acids can be performed (see Section 2.1.4.3.). This method can also be applied to the synthesis of hetarenothiepins such as furanothiepins.67... 

In contrast. naphthalene-2,3-dicarbaldehyde and AI,V-bis(cyanomethyl)-4-chloroaniline in the presence of potassium methoxide yield the expected 3//-naphtho[2,3-d]azepine 68.100... 

Ring expansions of 3-aryl-7-azido-2-chloroquinolines, e.g. 21, in potassium methoxide-meth-anol/dioxane yield mixtures of the expected 3-aryl-2-chloro-7-methoxy-9//-pyrido[2,3-f]pyrid-ines, e.g. 22, and the 2,7-dimethoxy derivatives, e.g. 23, formed by nucleophilic displacement of the 2-chloro group.154 ... 

Bismuth phthalocyanines of the type PcBiX can be prepared in solution by the reaction of bismuth(III) halides with PcLi2 or in a molten mixture of phthalonitrile and bismuth(III) halide.166 The sandwich-like complex [Pc2Bi]- can be obtained by slowly adding potassium methoxide to a melt of bismuth(III) oxonitrate and phthalonitrile.167... 

To a solution of potassium methoxide (0.2 mmol) in HMPA (10 ml) (CAUTION—CANCER SUSPECT AGENT), heated to 65°C, was added (E)-oct-4-ene oxide (1.2 mmol), then hexamethyldisilane (1.8 mmol) in HMPA (5ml), and the yellow mixture was stirred at 65°C for 3h. The cooled mixture was poured onto saturated brine, and extracted with pentane (2 x 25 ml). The combined organic extracts were dried and concentrated, to give oct-4-ene (1.15 mmol, 96%, 99 1 (Z) (E) by g.I.c.). 

Not all fused systems can be fully aromatic. Thus for phenalene (37) there is no way double bonds can be distributed so that each carbon has one single and one double bond. ° However, phenalene is acidic and reacts with potassium methoxide to give the corresponding anion (38), which is completely aromatic. So are the corresponding radical and cation, in which the resonance energies are the same (see p. 55). ° ... 

When epoxides such as tra s-3-hexene-epoxide 1885 are heated to 65 °C with hexamethyidisiiane 857 and potassium methoxide in anhydrous HMPA, trimethylsilyl potassium 1882 is generated in situ to open the epoxide rings and give 1886, which subsequently looses potassium trimethylsilanolate 97 to afford olefins with inverted stereochemistry, for example as cis-3-hexene 1887, in high yield [103]. The reaction also proceeds at 65 °C in THF, rather than HMPA, if 18-crown-6 is added [103a] (Scheme 12.29). 

Arsenic pentafluoride, Potassium methoxide See Arsenic pentafluoride Benzene, etc. 

At the end of the heating period the contents of the flask will have solidified. To the cold mixture 40 ml. of water is added to hydrolyze the potassium methoxide and precipitate the pyrimidine the fine crystals are filtered and dried. The crude product is placed in a 500-ml. distilling flask with 250 ml. of purified kerosene (Note 3). On distilling the kerosene, the pyrimidine codistils and solidifies in the receiving flask to a snow-white mass of crystals. These are filtered, washed well with petroleum ether, and dried in an oven at 100°. The yield of pure material, melting at 182-183°, is 27.5-28.7 g. (67-70%) (Note 4). 

Potassium methoxide in benzene also works well as a nucleophile in the transformation (233 -234), where R=H or alkyl (Scheme 3.157, Eq. 1) (204, 205). 

The iso-LSD salt can be converted back into the base by the addibon of methanolic KOH or potassium methoxide to the mother liquor. The resulting mixture should be added to a separatory funnel containing salt solution and ethylene dichloride. The LSD base is extracted into the ethylene dichloride layer (the lower layer). The lower layer is removed and fresh ethylene dichloride used to extract the last traces of LSD base from the salt water-base mixture. The ethylene dichloride extracts are combined, dried with MgSO, decolorized and filtered through diatomaceous earth as earlier. I he resulting ethylene dichloride solution may be combined with the chloroform solutions of iso-LSD which eluted from the chromatographic column. The combined solution may be evaporated to dryness under reduced pressure. 

The dry iso-LSD base can then be dissolved in methanol and potassium methoxide added. The resulting mixture is stirred for about 30 minutes. During this time isomerization takes place about 70% of the iso-LSD is converted into the desired normal form of LSD. 

NOTE If you only have mother liquors to isomerize, the second mixing with potassium methoxide is unnecessary. Simply prolong the initial mixing to about V i hour. 

The small effect on reaction rates of the addition of crown ethers to the lower alcohols was also observed in the reaction of potassium acetate with 1-bromobutane in ethanol (Hirao et al., 1978a,b). The displacement of fluorine in either o-nitro- or p-nitro-fluorobenzene by a methoxy group, by reaction with potassium methoxide in methanol was hardly influenced by the presence of dicyclohexyl-18-crown-6 (Del Cima et al., 1973). Mariani et al. (1978), too,... 

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