Acid Hydrazide Reagent

Dipping solution Dissolve 1 g isonicotinic acid hydrazide (4-pyridinecarboxylic acid hydrazide, isoniazide) in 100 ml ethanol and add 500 gl trifluoroacetic acid [1] or 1 ml glacial acetic acid. 

Spray solution Dissolve 0.8 g isonicotinic acid hydrazide in 200 ml methanol and add 1 ml hydrochloric acid (25%) [6] or glacial acetic acid [2]. 

Storage Both solutions may be kept in the refrigerator for one week at 

Isonicotinic acid hydrazide forms fluorescent hydrazones with ketosteroids. 

The chromatograms are dried in a stream of cold air, immersed in the dipping solution for 20 s or sprayed evenly with spraying solution, then dried in the air and left for a few minutes at room temperature. 

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Isonicotinic acid hydrazide reagent 318 Isoprenaiine 395,396 Isoprenoid compounds 44 Isopulegol 59 Isoquercitrin 279, 280, 323 Isoquinoline alkaloids 46, 66, 262 Isorhamnetin 323 Isothiazolones, microbiocidal 45 Isothiocyanates 75 Isotopes, j8-radiation-emitting 41 -, detection limits 41 Itaconic acid 61... 

Prostaglandins 195—197, 242 — 244, 273, 274,376, 411,413, 430, 438 Protocol form example 133 Prunasin 179,181 Psychopharmaceuticals 364 Purines 44, 266, 438, 439 Pyrazolidine derivatives 426 Pyrethroid insecticides 359 Pyridine alkaloids 66 4-Pyridinecarboxylic acid hydrazide reagent 318... 

Detection. Layer dipped into isonicotinic acid hydrazide reagent for 20 s and then into chloroform-liquid paraffin (9 1) to enhance and stabilize fluorescence. 

Starting Molecule d-iso-Lysergic acid hydrazide Reagents Acetylacetone d-2-AminobutanoM... 

Get an aliquot SOpg.mL-i of the reducing sugar sample, add 5mL p-hydroxy benzoic acid hydrazide reagent (mixed in the same day) shake in vortex, incubate in water bath at 100°C by six minutes, cool until room temperature, and read the absorbance in spectrophotometer at 410nm... 

As mentioned before for other azolide reactions, acylations can be carried out with polymer-supported azolides as acylating reagents. For example, acetic acid hydrazide can be prepared with a polymer of l-acetyl-4-vinyl-imidazole/divinylbenzene (96 4) and hydrazine (no diacylation occurs when this method is used) [122]... 

Kwakman et al. [65] described the synthesis of a new dansyl derivative for carboxylic acids. The label, N- (bromoacetyl)-A -[5-(dimethylamino)naphthalene-l-sulfonyl]-piperazine, reacted with both aliphatic and aromatic carboxylic acids in less than 30 min. Excess reagent was converted to a relatively polar compound and subsequently separated from the derivatives on a silica cartridge. A separation of carboxylic acid enantiomers was performed after labeling with either of three chiral labels and the applicability of the method was demonstrated by determinations of racemic ibuprofen in rat plasma and human urine [66], Other examples of labels used to derivatize carboxylic acids are 3-aminoperylene [67], various coumarin compounds [68], 9-anthracenemethanol [69], 6,7-dimethoxy-l-methyl-2(lH)-quinoxalinone-3-propionylcarboxylic acid hydrazide (quinoxalinone) [70], and a quinolizinocoumarin derivative termed Lumarin 4 [71],... 

Condensation of isoniazid (isonicotinic acid hydrazide) with any a" -3-ketosteroid in acidic medium affords a yellow color conjugate, allowing the determination of 10-40 pg of the steroid [73]. The reagent is prepared by dissolving 0.8 g of isoniazid in 100 mL of methanol containing 1 mL of concentrated HCl, and then 12.5 mL of this solution is further diluted to 100 mL with methanol. To a 2 mL methanolic sample solution of the 3-ketosteroid is added 2 mL of the reagent. The mixture is allowed to stand at room temperature for an hour, and then the absorbance of the resulting colored solution is measured at 380 nm. In a 1 cm spectrophotometer cell, an absorbance of 0.3 will be produced by 42 pg of cortisone, 34 pg of prednisolone, 29 pg of prednisone, or 32.5 pg of dexamethasone [72]. 

Sastry et al. used iodine and isonicotinic acid hydrazide for the spectrophotometric determination of diloxanide furoate in tablets and in syrups [30]. Powdered tablets or syrup were dissolved in methanol and hydrolyzed under reflux with dilute hydrochloric acid. The mixture was cooled, and excess HCI removed under vacuum. The hydrolysate was dissolved in and diluted with water. Iodine solution and the isoniazid solution were added at two minute intervals to a potassium h) drogen phthalate/HCl buffer solution (pH 3), and diluted with water. The solution was set aside for 10 minutes, whereupon the absorbance was measured at 630 nm against a reagent blank. 

GABA synthesis inhibitors act on the enzymes involved in the decarboxylation and transamination of GABA. Glutamic acid decarboxylase (GAD), the first enzyme in GABA biosynthesis, is inhibited easily by carbonyl reagents such as hydrazines [e.g., hydrazinopropionic acid (4.164) or isonicotinic acid hydrazide (4.165)], which trap pyridoxal, the essential cofactor of the enzyme. A more specific inhibitor is allylglycine (4.166). All of these compounds cause seizures and convulsions because they decrease the concentration of GABA. 

A one-step synthesis of 1,3,4-oxadiazoles from readily available carboxylic acids and acid hydrazides was mediated by the polymer-supported reagent... 

Further nucleophilic reagents used to cleave 2-amino-l,3,4-oxadiazoles include alcoholic potash, primary amines, hydrazine hydrate, phenylhydrazine hydrochloride, acid hydrazides, semicarbazide, thiosemicarbazide, ammonium hydrogen sulfide, and hydrochloric acid. 

Aromatic aUazines and ketazines. Polyphosphoric acid is an excellent catalyst and solvent for production of amines from aromatic aldehydes and ketones in the presence of various carbonyl reagents, for example, hydrazine, its salts, semicarbazide hydrochloride, toluene/i-sulfonohydrazide, and acid hydrazides. The reaction is usually complete at 100° within 15 min. The reaction is not useful in the case of aliphatic carbonyl compounds. 

Potassium ferricyanide [potassium hexacyanoferrate(lll)], K3Fe-(CN), in the presence of a base, dehydrogenates hydroaromatic compounds to aromatic compounds [919] and can cause dehydrogenative cy-clizations [920]. The reagent is used for the conversion of acid hydrazides into aldehydes [921], of sterically hindered phenols into phenoxy radicals [922, 923], and of primary amines into nitriles [924], Tertiary amines are demethylated to secondary amines [925, 926]. 

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