Über die Verwendung von Tüpfelreaktionen zum Nachweis von organischen Verbindungen. (II.)

The Hydroxamic Acids.

“…It was found to be a better conductor of electricity than ferric acetylacetonate, gave no precipitate with potassium ferrocyanide, reacted only very slowly with ammonia to give ferric hydroxide, and was dissociated only by a high acid concentration. This stability differentiated these compounds from the colored enolates and phenolates (66, [74][75][76].…”

“…Since it is known that derivatives of the general formulas RCONHOR/ or RC(OH)-NOR' do not give color reactions with ferric chloride, while com- The color test with ferric chloride is extremely sensitive. It will detect the presence of 2 7 of a carboxylic acid or acid anhydride (74)(75)(76).…”

The separation of esters of choline by filter-paper chromatography

“…The first method employed a reaction first used by Feigl, Anger & Frehden (1934, cf. Feigl, 1939 as the basis of a spot test, and later applied to the quantitative estimation of acyl phosphates (Lipmann, 1946) and acetylcholine (Hestrin, 1949).…”

Colorimetric Determination of Panthenol and Pantothenates

“…Crokaert (1) described a color reaction between 3-alanine, one of the hydrolytic cleavage products of pantothenic acid, and 1,2n aphthoquinone-4-sodium sulfonate, while Szalkowski, Mader, and Frediani (9) reacted 3-alanine with 2,4-dinitrophenylhydrazine and determined colorimetrically the precipitated hydrazone in pyridine. Hestrin (6) suggested that the color reaction for esters and lactones, described by Feigl et al (4), might be utilized for a quantitative procedure. This reaction had previously been used by Lipmann and Tuttle (7) for the determination of acyl phosphates.…”

“…The method described is based upon Feigl's (4) color reaction after hydrolysis of panthenol or pantothenates to pantoyl lactone.…”