Pyridine acetate

Apply extracts of cereals or fungal cultures apply [66] 50 pi pyridine — acetic anhydride (1 -I-1) on top remove the excess reagent in a stream of cold air and chromatograph. The reagents can also be applied via gas phase... 

Two surprising observations were made in the course of this work first that the enol acetate (5) is stable under the conditions for formation of (6) from (4) second, that the course of the buffered bromination of (5) depends on the conditions used. Thus, in the presence of epichlorohydrin, (7) is the sole isomer produced, whereas in pyridine-acetic acid approximately equal amounts of (7) and (8) are formed. It was suggested that this difference is inherent in the mechanism and not a result of isomerization of (7) to (8) during the course of the reaction. 

This was also accomplished with BaRu(0)2(OH)3. The same type of conversion, with lower yields (20-30%), has been achieved with the Gif system There are several variations. One consists of pyridine-acetic acid, with H2O2 as oxidizing agent and tris(picolinato)iron(III) as catalyst. Other Gif systems use O2 as oxidizing agent and zinc as a reductant. The selectivity of the Gif systems toward alkyl carbons is CH2 > CH > CH3, which is unusual, and shows that a simple free-radical mechanism (see p. 899) is not involved. ° Another reagent that can oxidize the CH2 of an alkane is methyl(trifluoromethyl)dioxirane, but this produces CH—OH more often than C=0 (see 14-4). ... 

Singh utilized anionic dyes to detect gramicidin on paper chromatograms184. Paris and Theallet described three paper chromatographic systems for gramicidin185. Ritschel and Lercher described two solvent systems for antibioticsiOD. The solvent systems were butanol-pyridine-acetic acid-water (15 10 3 12) and water saturated butanol-water saturated ethyl ether-acetic acid (5 1 1) on Schleicher and Schull 2043b paper. The antibiotics were visualized by ninhydrin. 

Toyo No.50 Descending for 9 hrs. n-Butanol/pyridine/ acetic acid/water (15 10 3 12)... 

The one-step condensation to convert 2-butanone, ethyl cyano-acetate, and hydrocyanic acid to ethyl 2,3-dicyano-3-methyl-pentanoate is a modification of the procedure described by Smith and Horowitz 6 in which pyridine acetate was employed as the catalyst. Higson and Thorp 6 employed a two-step procedure in which butanone was converted to its cyanohydrin, which in turn was condensed with ethyl cyanoacetate. 

Cabon tetrachloride, n-hexane, chloroform, ACN, acetone, THF, pyridine, acetic acid, and their various mixtures were applied as mobile phases for adsorption TLC. Methanol, 1-propanol, ACN, acetone, THF, pyridine and dioxane served as organic modifiers for RP-TLC. Distilled water, buffers at various pH (solutions of and dipotassium hydrogen phosphate or potassium dihydrogen phosphate) and solutions of lithium chloride formed the aqueous phase. Carotenoids were extracted from a commercial paprika sample by acetone (lg paprika shaken with 3 ml of acetone for 30 min), the solution was spotted onto the plates. Development was carried out in a sandwich chamber in the dark and at ambient temperature. After development (15 cm for normal and 7cm for HPTLC plates) the plates were evaluated by a TLC scanner. The best separations were realized on impregnated diatomaceous earth stationary phases using water-acetone and water-THF-acetone mixtures as mobile phases. Some densitograms are shown in Fig.2.1. Calculations indicated that the selectivity of acetone and THF as organic modifiers in RP-TLC is different [14],... 

Arctic Acid Acetic Anhydride J Pyridine Acetal dot Paraldehyde... 

Acetylated aldose oximes with a ring structure have also been obtained during the preparation of the nitriles, both with sodium acetate-acetic anhydride and with pyridine-acetic anhydride. Thus it appears that under these conditions at least a certain amount of the oxime is present in the ring form. 

Preparation of acetylated nitriles from oximes with pyridine-acetic anhydride. Penta-acelyl-n-glucosaminonitrile. One gram of D-glucosamine oxime hydrochloride was treated with 6 ml. of pyridine and 6 ml. of acetic anhydride and kept at 20° until solution had occurred. The solution was then concentrated and the crystalline residue was recrystallized from ethanol yield 1.8 g. (84%), m. p. 126°. 

With L-fucose oxime Restelli de Labriola and Deulofeu obtained the nitrile in 52% yield by the action of pyridine-acetic anhydride. 

Pentapropionyl-D-galactononitrile has been prepared in 52 % yield by Gim6nez from the oxime and pyridine-acetic anhydride. Degradation with ammonia-silver oxide produced D-lyxose diacetamide in 30% yield. 

Goethite CO2 SO2 pyridine, acetic acid vapour, CO2, nitric oxide, trimethyl chlorosilane Russell et ah, 1975 Kaneko and Inouye, 1981 Rochester and Topham, 1979 c... 

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