Ethanol in pyridine

Chlorocarbonylphenyl organo telluriums were converted to ethyl esters by heating with absolute ethanol in pyridine ... 

Fig. 2.—Formation of D-Glucose iV.iV -Diphenylformazan at Various Time Intervals (----in water,------- in 50% ethanol,.in pyridine).

Orthorhombic crystals, d 3.465. mp 506-509" also reported as 488 Ball, loc. cit Sublimes at 473. bp 520. Very hygroscopic. Freely sol in water. By saturating the coned viscous soln with HBr, the tetrahydrate is formed. So) in ethanol, in pyridine (185.6 g/1). in ethyl bromide (1.0 g/l). Forms addition compounds with amines, alcohols. Keep lightly closed. 

Due to the difference in acidity of phenol relative to simple aliphatic alcohols, its spectra in different solvents are quite different from those of methanol and ethanol. In solvents of low hydrogenbonding capability, phenol shows both free and bonded OH first overtones because the solvent cannot bond the phenol completely. In solvents that are more capable of hydrogen bonding, phenol behaves like the alcohols, except that the sequence is accelerated for example, the spectrum of phenol in N, A-dimethylformamide appears similar to the spectrum of ethanol in pyridine. 

Phosphorus trichloride reacts readily with three equivalents of an alcohol e.g, ethanol, in the presence of a tertiary amine such as pyridine, dimethyl-aniline, or diethylaniline, to form triethyl phosphite and hydrogen chloride, the latter being immediately neutralised by the tertiary amine. 

Norethindrone may be recrystakhed from ethyl acetate (111). It is soluble in acetone, chloroform, dioxane, ethanol, and pyridine slightly soluble in ether, and insoluble in water (112,113). Its crystal stmcture has been reported (114), and extensive analytical and spectral data have been compiled (115). Norethindrone acetate can be recrystakhed from methylene chloride/hexane (111). It is soluble in acetone, chloroform, dioxane, ethanol, and ether, and insoluble in water (112). Data for identification have been reported (113). The preparation of norethindrone (28) has been described (see Fig. 5). Norethindrone acetate (80) is prepared by the acylation of norethindrone. Norethindrone esters have been described ie, norethindrone, an appropriate acid, and trifiuoroacetic anhydride have been shown to provide a wide variety of norethindrone esters including the acetate (80) and enanthate (81) (116). 

The reaction of appropriate 1,3-diketones (302) with hydroxylamine hydrochloride in pyridine (79MI41601) has been reported to result in a regiospecific synthesis of 3-alkyl-5-arylisoxazoles, as has the reaction of an a -bromoenone (307) with hydroxylamine hydrochloride in ethanol in the presence of potassium carbonate (81H(16)145). Regiospecific syntheses of 5-alkyl-3-phenylisoxazoles also result from the reaction of an a-bromoenone (307) with hydroxylamine in the presence of sodium ethoxide (81H(16)145). 3-Aryl-5-methylisoxazoles were prepared from phosphonium salts (304) and hydroxylamine (80CB2852). 

Reductive alkylation by alcohol solvents may occur as an unwanted side reaction 22,39), and it is to avoid this reaction that Freifelder (20) recom mends ruthenium instead of nickel in pyridine hydrogenation. Alkylation by alcohols may occur with surprising ease 67). Reduction of 18 in ethanol over 10% palladium-on carbon to an amino acid, followed bycyclization with /V,/V-dicyclohexylcarbodiimide gave a mixture of 19 and 20 wiih the major product being the /V-ethyl derivative 49,50). By carrying out the reduction in acetic acid, 20 was obtained as the sole cyclized product 40). 

The above substance is dissolved in pyridine (15 ml) and acetic anhydride (7.5 ml), and heated on the steam bath for % hour. The product (lllb) crystalli2es from aqueous ethanol In leaflets, MP 237° to 239°C. An analytical sample has MP 241° to 243°C. 

The pyridine ligand in some alkenyl cobalt(III) DMG complexes may be replaced by methyl or ethyl phosphite by addition of the phosphite to a solution of the (DMG)2 complex in ethanol. In a similar manner aniline may be displaced by (CH30)3P from [CH2=CHCo(DMG)2C6HjNH2] (129). 

Spiroindolinobenzothiopyrans can be prepared by condensation of Fischer s base with thiosalicylaldehyde derivatives 46 in ethanol, as shown in Scheme 22.71,89 93 Reaction of 1,2,3,3-tetramethylindolinium salt with carbamoylthiobenzaldehyde,92 which is an intermediate for preparation of thiosalicylaldehyde, also gives the spirobenzothiopyran in high yield via the corresponding indolinium salt, as shown in Scheme 22.94 Conversion of spirobenzopyrans to the corresponding spirobenzothiopyran by phosphorous pentasulfide in pyridine or xylene is possible, but the purification of the product is difficult. 

The method constitutes a simple preparation of ethanol-in-soluble cinnamic acids, of a high degree of purity when compared with the Perkin reaction 6 or the usual procedure for the Doebner reaction,6 which uses a large excess of pyridine. A useful modification of this reaction is to warm the reactants on a steam plate in the absence of alcohol.7 8... 

Figure 4. Absorption and emission of TIN and MT in different solvents (I) absorption of TIN in methylcyclohexane/isopentane at 150 K (II) absorption of TIN in ethanol/methanol at 150 K (III) absorption of MT in hexane at 296 K (IV) (a) fluorescence and (b) phosphorescence of TIN or MT in 20 20 1 ethanol/ether/pyridine at 90 K (V) fluorescence of TIN in methylcyclohexane/isopentane at 90 K.

Part 28 Determination of 1,1,1-trimethylolpropane (TMP) in food simulants Aqueous food simulants are saturated with potassium carbonate and extracted with ethanol/ethyl acetate. After evaporation of solvent the extracted TMP is silyated with trimethylsilylimidazole in pyridine and determined by GC with flame ionisation detection... 

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