Methanolic pyridine

When hemin (1) is treated with gaseous hydrogen chloride in anhydrous methanol/pyridine in the presence of iron(II) sulfate, protoporphyrin dimethyl ester (2), the metal-free ligand of hemin. is produced in almost quantitative yield. This compound is quite sensitive to oxygen... 

In aqueous solution especially, the current yield is distinctly lower furthermore, solubility problems can occur when the salt-deficit method is used. In aqueous solution, a-amino- or a-phenyl substituted carboxylates lead mainly to decomposition products, whilst in dry methanol or methanol-pyridine, coupling products were obtained with a-phenyl- and a-acetylaminocarboxylates [49]. 

Several of these steroid derivatives underwent elimination of phosphorodichloridate anion, giving hydrocarbon products, rather than ester formation when treated with methanolic pyridine. Pyrophosphoric acid itself has been used to phosphorylate (2-hydroxymethyl)pyridine. ... 

The reaction of the trichloromethylarenes 146 with thiosemicarbazide 138 in a boiling methanol-pyridine mixture afforded the 2-amino-5-aryl-l,3,4-thiadiazoles, while under similar conditions trichloromethylarenes 146 were converted to the diaryl-1,3,4-thiadiazoles with thiobenzhydrazide 147 (Equation 52, Table 7) <1996RCB1185>. 

It was found that the rate constant of the forward decomposition of the surface bidentate formate (DCOO ) to produce D2 and C02 increased from 0.34X10 4 sec-1 under vacuum to 5.3 X10-4 sec-1 under ambient water. Electron donors such as NH3, CH3OH, pyridine, and THF also increased the decomposition rate the rate constants of the forward decomposition of the surface formates at 553 K were determined to be 28.0X10 4, 7.7X10 4, 8.1X10-4, and 6.0X10 4 sec-1 under NH3, methanol, pyridine, and THF vapors (0.4 kPa), respectively. It is likely that the driving force for the forward decomposition of the formate is electron donation of the adsorbed molecule to the Zn ion on which the bidentate formate adsorbs. The reactant-promoted mechanism for the catalytic WGS reaction on ZnO is illustrated in Scheme 8.2. 

The arylation of potassium phenoxide has been studied by Litvak and Shein (1976). In the absence of crown ether the rate of reaction with p-nitrobromobenzene in various solvents increases in the order dioxan < methanol < pyridine < DMSO. In the presence of either 18-crown-6 [3] or dibenzo-18-crown-6 [11], the order of the reaction rates in dioxan and methanol is reversed (Table 22). The effect of crown ether addition on the rate... 

The product is soluble in methanol, pyridine, and dimethyl sulfoxide, insoluble in nonpolar solvents, e.g., heptane and toluene.The H-NMR spectrum of the polymer in D2O shows one signal at 1.95 ppm (-CH2-CH2). 

White trigonal crystals hygroscopic refractive index 1.735 density 2.38 g/cm melts to a clear melt at 264°C decomposes at 600°C highly soluble in water (90g/100g at 28° C solubility greatly increases with temperature (234g/100g at 100°C) also, soluble in methanol, pyridine and ammonia solution. 

Protection of a hydroxyl group at C-5 in a nucleoside has been performed161 by using crotonic (2-butenoic) and related esters. A remarkably selective removal of the 5 -0-acyl group was observed on treatment of 3 -0-acetyl-5 -0-(4-methoxycrotonoyl)thymidine with 0.05 M hydrazine hydrate in methanol-pyridine for 2 hours at 20°. 

Fuller s earth (hydrated aluminosilicate) Magnesium oxide Charcoal Alumina Magnesium trisilicate Silica gel Calcium hydroxide Magnesium carbonate Calcium phosphate Calcium carbonate Sodium carbonate Talc Inulin Sucrose = starch Petroleum ether, b 40-60°- Petroleum ether, b 60-80°. Carbon tetrachloride. Cyclohexane. Benzene. Ethyl ether. Chloroform. Ethyl acetate. Acetone. Ethanol. Methanol. Pyridine. Acetic acid. 

Model compounds and drinking water (>10 L) sequential Soxhlet extraction with methanol, pyridine, and ethyl ether, 8 h each see ref 5 and 7 17... 

Fig. 10 Chromatogram of a pigment extract form a natural seawater sample on a polymeric column (Vy-dac 201 TP). Mobile phases (a) methanol-pyridine (0.025 M, pH adjusted to 5.0 with acetic acid) (80 20, v/v) (b) acetontrile-acetone (70 30, v/v). (From Ref. 77.)...

N,N-dImethylformamide, see N,N-dimethylformamide-methanol-water -pyridine, see methanol-pyridine-water -2-propanol, see 2-propanol-water Pyridine, see pyridine-water... 

Investigation of methanol-pyridine complexes, on the other hand, produced a relatively narrow (75 cm 1 FWHM) bleached hole that is burned into the 260 cm 1 FWHM OH-stretch (v = 0 -> 1) absorption band. The methanofpyridinc complex OH-stretch absorption band was better fit by a Gaussian function than with a Lorentzian bandshape, indicating this system is inhomogeneously broadened on the >1 ps timescale. 

Compound oq, Methanol- Pyridine Cmpd. Time (sec.) (Yield %)... 

Certain bivalent tin salts have solubilities in nonaqueous solvents, e.g. tin(ll) chloride is soluble in many organic solvents, including alcohols, acetone, THF, and pyridine, probably to give rise to three-coordinate pyramidal [SnCl2-L]-type complexes. Other selected solubilities are SnBr2 in methanol, pyridine, or THF and tin(II) formate in H0(CH2)30H. Bivalent tin species are also solnble in acetonitrile solution, to give [Sn(MeCN) ] + (n = 2, 3, or 6), and in liquid ammonia, to give [Sn(NH2)3] . 

These ketals can also be synthesized from 9-hydroxyellipticine (3) and lead tetraacetate/methanol/pyridine [room temperature (rt), 3 hr]. In similar fashion, the ribonucleotide adduct 397 was synthesized and characterized by an exhaustive NMR study including nuclear Oveihauser effect (NOE) measurements to establish the precise stereochemistry (775). 

Catalyst for tht coupling of terminal acetylenes. Cuprous chloride catalyzes the oxidation of terminal acetylenes in methanol-pyridine by air or oxygen in amounts of only 0.012 mole per mole of the acetylene, and the diacetylene is obtained in... 

Anhydrous material, prepared by refluxing the hydrate with acetic anhydride and washing the insoluble product with dry ether, is used in methanol-pyridine for the oxidative coupling of terminal acetylenes to diynes. Mechanism. Review. ... 

Table 5 (column 3) shows the effect of ultrasound upon the product ratio from methanol/pyridine. There is now 53% bibenzyl, 32% methyl ether, and 6% methyl ester (with total 5% of other products), suggesting only a slight shift towards the two-electron products, but with an overall diminution of solvent discharge and side reactions. Phenyl acetate electrooxidation, however, is known to favor the one-electron route to bibenzyl in a wide range of conditions [188], and to be much less sensitive to mechanistic switches by manipulation of parameter than is cyclohexane carboxylate electrooxidation [180]. This trend remains even under ultrasound. 

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