The mechanism of the reaction of the Nash and the Sawicki aldehyde reagent

Abstract

Synthetic and chromatographic studies are presented on the Nash and Sawicki colorimetric methods for quantitating formaldehyde. It is shown that the actual color-forming agent in the Nash method is an isolable iminodione formed insitu by reaction of the two components. Explanation is given for differences between these two methods.

Spectrophotometric analysis of Azithromycin and its pharmaceutical dosage forms: Comparison between Spectrophotometry and HPLC

“…This reaction is similar to the Nash method which is based on the Hantzsch pyridine synthesis where formaldehyde reacts with a reagent consisting of acetone and concentrated ammonium acetate. 28 Based on this method, when traces of formaldehyde are added to approximately neutral solutions of acetone and ammonium salt, a yellow colored chomogen gradually develops owing to the formation of diacetyldihydrolutidine. This yellow colored chromogen named as 3,5-diacetyl-2,6-dihydrolutidine exhibits fluorescence.…”

3-Amino-5,5-dimethylcyclohex-2-enone in the synthesis of heterocyclic compounds (review)

“…The use of cyclic enamines in reactions with biselectrophiles is one of the methods for the synthesis of condensed heterocycles. The readily available 3-amino-5,5-dimethylcyclohex-2-enone (1), obtained from dimedone and ammonia or ammonium acetate (hydroxide) [1][2][3][4][5][6][7][8], is a convenient starting substrate for the synthesis of heterocyclic compounds differing in the number of rings, the size of the heterocycle, and the number and mutual arrangement of heteroatoms. The nucleophilic centers in the enamino ketone fragment of the molecule of compound 1 are the N and C(2) atoms.…”

Synthesis of pyridines by cyclocondensation of acetyl and benzoyl pyruvates with enamines

“…4-Aminopent-3-en-2-one (3b), 3-Amino-1-phenyl-but-2-en-1-one (3c), 3-Amino-1-cyclo-propylbut-2-en-1-one (3d), and 3-Amino-3-phenylacrylonitrile (4a) were obtained as described in [3,[12][13][14]. 1-Methyl-2-nitrovinylamine (3c) was obtained by the transamination of (1-methyl-2-nitrovinyl)phenylamine [15][16][17].…”