Pyridine ethanol

Dioxotetrakis(pyridine)rhenium(V) trifluoromethanesulfonate4 is prepared by dissolving 0.7 g of [Re02(Py)4]Cl-2H20 (1.15 mmol) in 60 mL of a 2/49/49 (v/v/v) pyridine/ethanol/water solution. Any solid impurities are removed by filtration. Then, 1.5 g of LiCF3S03 (9.6 mmol), dissolved in a minimum amount of water, is added and the solution is concentrated on a rotary evaporator. The solid product is removed by filtration, washed with cold ethanol/diethyl ether and diethyl ether, and dried in vacuo. (Yield 50%, ca. 0.4 g). 

Diaryl ditellurium compounds, when heated in pyridine, ethanol, or acetic acid with selenium dioxide, produced the corresponding bis[aryltelluro] selenium and derivatives of these compounds with oxygen bonded to tellurium and selenium4. 

Pictet-Spengler cyclization of L-tryptophan with formaldehyde afforded the monochiral carboxylic acids 20a,b, whereas cyclization with acetaldehyde yielded the diastereomeric carboxylic acids 21a,b (23). Acids 20a,b with a hydrogen at C-1 are enantiomers, but acids 21a,b are diaste-reomers the cis isomer 21a was the major reaction product when the cyclization of L-tryptophan with acetaldehyde was carried out in the presence of sulfuric acid. Direct removal of the carboxy group in these acids is difficult, but it can be accomplished in several steps dehydration of the amides prepared from the acids with phosphorus oxychloride affords nitriles, and the nitrile group can be removed by reduction with sodium borohydride in pyridine-ethanol (31). 

PROP White to brownish-gray powder. Disagreeable odor. Sol in water, pyridine, ethanol less sol in acetone, ether, chloroform, pentane, benzene. 

Agreement with Raoult s Law is not a sufficient condition for ideality —though it is a necessary one (627). Occasionally a mixture capable of H bonding will form a pseudo-ideal system which obeys the equation. Pyridine-ethanol is an example (227) which must include H bonding, both in association of the alcohol and between the two components. The observed ideal behavior surely results from a fortuitous cancellation of effects. 

Vapor pressure pseudo-ideal H bond system, pyridine-ethanol. 

Bis(l,2-benzisothiazol-3(2H)-one 1, l-dioxidato)tetrakis(pyridine)vanadium-(Il) dipyridine forms deep red crystals (almost black). As obtained by the above procedure, the crystals are relatively large, and can be exposed to air for a few minutes without any apparent decomposition. They can be weighed in air without any problem. The compound is soluble in pyridine, ethanol, and, to a lesser extent, in warm tetrahydrofuran (THF), from which it is rccrystallized as [V(C7H4N03S)2(C5H5N)J-2H20. ... 

Conversion of disaccharide III.86 into glycosyl acceptor III.87 was achieved in 92% yield hy removal of the chloroacetyl ester with thiourea in pyridine-ethanol. Condensation of acceptor III.87 with imidate III.83 in the presence of trimethylsilyl triflate afforded the crystalline trisaccharide III.88 in 92% yield. Removal of the isopropylidene with aqueous acid followed hy selective benzoylation of C6 gave III.82 (90%, two steps). 

Fig. 7.—Upper Curve Mutarotation of n-Mannose Phenylhydrazone [c 0.9, pyridine-ethanol (9 1 by vol.)] Lower Curve n-Mannose Diphenylformazan Formation.

Fig. 8.—Upper Curve Mutarotation of L-Rhamnose Phenylhydrazone [c 1.27, pyridine-ethanol (l lbyvol.)] LowerCurve L-RhamnoseDiphenylformazan Formation.

Fig. 11.— Lower Curve Mutarotation of n-Galacturonic Acid Phenylhydrazone (pyridine-ethanol, 1 1 by vol.) Upper Curve n-Galacturonic Acid Af.AT -Diphenyl-formazan Formation.

Fig. 16.—Upper Curves Mutarotation of n-Glucose Phenylosazone in Pyridine-ethanol (1 1 by vol.) Lower Curves, n-Glucose Phenylosazone Formazan Formation (-----initial substance,.recovered substance).

Reaction of the mono-5-(phenylhydrazone) with diazotized aniline in pyridine-ethanol produced 1,2-0-isopropylidene-D-a 2/Zo-pentodiose 5-(iV,iV -diphenylformazan), and the l,5-bis(phenylhydrazone) gave xylo-pentodiose 1,5-bis(iV, iV -diphenylf ormazan)... 

Dissolved or suspended in ice-cold pyridine-ethanol and coupled with diazotized aniline solution, the phenylhydrazones of the oxidized polysaccharides lead to their vividly red diphenylformazans. ... 

Reductive decomposition of the formazans of oxidized polysaccharides, by means of hydrogen sulfide, as with the simple sugar formazans, yields sulfur-containing, nitrogenous polysaccharide derivatives which contain thionic acid phenylhydrazide groups. For example, when a pyridine-ethanol solution of oxy-starch formazan or oxy-dextrin formazan is saturated with hydrogen sulfide, the vividly red solution turns colorless and a yellow precipitate, which gives the Wuyts reaction characteristic of the thionic acid phenylhydrazides, separates. 

Unlike in the case of phenols, direct oxidative dimerization of quinones only takes place under drastic conditions and requires a hydroxy or amino group on the quinonoid double bond, as in Lawson 4c, the dye in Arabian henna. Since the work of Pummerer (1937), however, it has been known that monomeric 1,4-quinones can be oligomerized much more easily under acidic or basic conditions. [8] In pyridine/ethanol, or by wanning in glacial acetic acid, we have converted naphthoquinone, 1,4-anthraquinone, and nu-... 

Pyridine-ethanol Molecules with a high content of N and O... 

Pyridine ethanol was reacted with boranes, affording 2-substituted derivatives <86JOC4526, 88JCS(P2)1787,92JCS(P2)527>. Thus, for example, (273) was prepared (Equation (61)). Piperidine ethanol could also be used <85JOM(294)i>. 

The D-ido acetoxonium salt (62) exhibits both of the reactions characteristic of an ambident cation (see Section 1,3). With ethanol-pyridine, 62 reacts by the cis pathway to give the orthoester 65. It is noteworthy that, in pyridine solution, no equilibration takes place between the u-ido salt (62) and the o-gluco salt (59). After hydrolysis of solutions of these salts and subsequent further acetylation, the pure pentaacetates of D-idose or D-glucose, respectively, are recovered. It may be supposed that, in pyridine solution, a salt such as 62 is converted at once into the non-isolable pyridinium orthoester (67), whereby each further acetoxonium rearrangement is prevented. In pyridine-ethanol, the salt 62 evidently reacts initially to give the intermediate 67, which reacts further with ethanol to give the orthoester 65. 

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