Semicarbazide


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semicarbazide

[¦sem·i′kär·bə‚zīd]
(organic chemistry)
H2N‒NHCONH2 A reagent used to produce semicarbazones by reaction with aldehydes or ketones.

Semicarbazide

 

H2N—NH—CO—NH2, the hydrazide of carbamic acid. Semicarbazide occurs as colorless crystals; it has a melting point of 96°C (with decomposition) and is soluble in water and alcohol. Semicarbazide possesses chemical properties similar to those of hydrazine and hydrazine’s organic derivatives. Combined with acids, it yields salts, for example, semicarbazide hydrochloride (CH5N3O·HCl), with a melting point of 173°C); with aldehydes and ketones, it yields readily crystallizing semicarbazones, as seen in the reaction

R2C=O + H2NNHCONH2

→R2C=NNHCONH2 + H20

Semicarbazide readily condenses (for example, with β-diketones) to form heterocyclic compounds. It is obtained by, for example, the reaction of hydrazine with potassium cyanate (KOCN). Semicarbazide is used primarily in the identification of aldehydes and ketones.

References in periodicals archive ?
Figure 3(a) shows that benzylamine-induced hydrogen peroxide release was inhibited by 1 mM semicarbazide while being resistant to pargyline.
However, resveratrol and caffeic acid abolished benzylamine-induced signal at 1 mM, almost to a deeper extent than the reference inhibitor semicarbazide, while quercetin and pterostilbene impaired partially the benzylamine-induced signal.
pH > rpm > semicarbazide HCl > age of inoculum >[K.
12%) followed by age of inoculum and semicarbazide HCl (at level 2, 2; column 4; SI 63.
However, the latest evidence is understood to show that semicarbazide is produced during the heat treatment of an approved blowing agent (azodicarbonamide) used to make sealing gaskets in the lids of glass jars and bottles and that it migrates from the gaskets into food.
An ad hoc expert group was specifically asked by EFSA to advise further on possible risks to infants given that this is the consumer group for which potential exposure to semicarbazide on a body weight basis is likely to be the highest.
Hydrazinolysis of carbamate (3e) with hydrazine hydrate in refluxing ethanol furnished the corresponding semicarbazide (4).
PLP concentrations in plasma and erythrocytes were measured by HPLC using precolumn semicarbazide derivatization and fluorescent detection as described previously (16).
This seems to suggest that the derivatization approaches used by these laboratories [bisulfite (11), chlorite (7), and semicarbazide (13,14)] to increase the fluorescence sensitivity of PLP were all equally effective for quantifying PLP in this study and that quality control within the laboratory is the single most important issue.
We describe a simple, robust, reversed-phase HPLC method with precolumn derivatization using semicarbazide (11-13) that is suitable for the simultaneous measurement of PLP, 4-pyridoxac acid (PA), and PL in plasma and red cells and application of the assay in healthy individuals, patients with chronic disease, and critically ill patients requiring intensive care.
Unicell TS--Toluene sulfonyl semicarbazide for high temperatures.
semicarbazides, thiosemicarbazides and hydrazones are intermediates for the construction of pyrazolo[4,3-e][1,2,4]triazines [13].