Ammonium reineckate

Choline reineckate is used in the spectrophotometric determination of choline. Ammonium reineckate [13573-16-5] forms a water-insoluble complex with choline. The complex is soluble in acetone and a widely used method for determination of choline is by light absorption of acetone solutions... 

Ammonium reineckate (Reineckate salt) [13573-16-5] M 345.5, m 270-273 (dec). Crystd from water, between 30° and 0°, working by artificial light. Solns of reineckate decompose slowly at room temperature in the dark and more rapidly at higher temperatures or in diffuse sunlight. 

The remaining aqueous layer was then acidified with acetic acid a saturated aqueous solution of ammonium reineckate was added to a portion, but no precipitation occurred. No precipitate was noted with Valser s or Mayer s reagent. 

Spectrophotometric determination of niclosamide and thiabendazole in their binary mixtures (e.g., tablets) was realized by precipitating thiabendazole with ammonium reineckate at pH 3.0 selectively and reading the absorbance of the solution of the precipitate in acetone at 525 nm for thiabendazole and by measuring the dA/dA values at 405.8 nm in the first-derivative spectra of the remaining solution for niclosamide [52]. 

Amin and Issa [15] described an indirect atomic absorption spectrometric method for the determination of primaquine and other antimalarials. The method is based on the formation of their ion-associates with [Cd2+, Co2+, Mn2+, and Zn2+1] thiocyanate, ammonium reineckate, and/or sodium cobaltinitrate. 

Chlorpromazine was determined by precipitation with an excess of 0.2% ammonium reineckate solution, and titration of the unconsumed reagent bromatometrically after alkaline hydrolysis [67]. Excess hexathiocyanato-chromate was used as a precipitating reagent for chlorpromazine, whereupon the unconsumed reagent was determined with KBr03 in the filtrate [68]. 

Kum-Tattbt> identified meperidine by preparing the ammonium reineckate derivative and determining several physical properties of the reineckate including its ultraviolet and visible absorption spectra in ethanol. Basu and Dutta57 quantitatively determined meperidine by dissolving the ammonium reineckate in acetone and measuring the absorbance at 525 m/i. 

Ammonium reineckate Add 0.2 g hydroxylamine to a saturated solution of 4% ammoniiun reineckate, and acidify with dilute HCI. A pink precipitate will appear... 

A colorimetric method for the determination of amodiaquine in tablets or powders has been reported (31). The drug is dissolved in 0.1 N hydrochloric acid, treated with acidic ammonium reineckate, the precipitate dissolved in acetone, and the absorbance measured at 525 run. The results compare favourably with those obtained by the official methods. 

For preparative purposes, purifications based on the precipitation of alkaloids are sometimes employed. A crude extract of the alkaloids is made with aqueous acid, subsequently the alkaloids are precipitated with reagents such as Mayer s reagent (IM mercury chloride in potassium iodide) or Reinecke s salt (5% ammonium reineckate in 30% acetic acid) at pH 2, or picric acid (saturated aqueous solution) at pH 5-6. After collection of the precipitate by filtration or centrifugation, the precipitate is dissolved in an organic solvent (acetone-methanol-water 6 2 1). The complexing group is then removed by means of an anion exchanger (Jordan and Scheuer 1965 Verpoorte and Baerheim Svendsen 1976). This method is particularly suited for the purification of quaternary alkaloids. 

Ammonium reineckate (Reineckate salt, NH4[Cr(NH3)2(SCN)4] ]13573-16-5] M 336.4 (anhydrous), m 270-273°(dec). Ciystalhse it from water, between 30 and 0 , while working imder artificial light. Solutions of reineckate salt (aqueous or alcoholic) decompose slowly at room temperature in the dark ( 2 weeks) and more rapidly at higher temperatures or in diffuse sunlight. The solutions are blue in coloiu and liberate HCN (POISONOUS). Store it dry in the dark under a vacuum. [Dakin Org Synth Coll Vol II555 1943.]... 

These workers suggested that after extraction of a sample with methanol and hydrolysis with barium hydroxide, the pH be brought to 4-5 with glacial acetic acid. The hydrolyzate was made up to a definite volume and filtered, and the choline was precipitated with an aqueous saturated solution of ammonium reineckate while kept in an ice bath for 3 hours. Best results were obtained if sintered glass filters, chilled in an ice bath, were used to collect small amoimts of the precipitate. The crystals were washed three times with 2 ml. of ice-cold water saturated with choline reineckate. Low recovery values were obtained if the wash solution was not saturated with choline reineckate. Water was removed from the precipitate by continued aspiration which was necessary since water absorbs light less strongly at 327 mu than does acetone. 

Tissue samples or extracts are refluxed for 4 hours in a saturated solution of Ba(OH)i and then filtered through a pad of Super-cel in a Buchner funnel. The clear filtrate (approximately pH 12.5) is not neutralized, but is chilled and 6 ml. of a 3% solution of ammonium reineckate in methanol is added. The solution is stored in the cold room, shielded from light for 1.5 hours, and then filtered with suction through a pad of Super-cel in a Bflchner funnel, previously washed with... 

The substance can be assayed by non-aqueous titration (p. 792) and forms an insoluble compound with ammonium reineckate. 

Dissolve about 01 g in 40 ml of water and add 20 ml of dilute sulphuric acid followed by 30 ml of 1 per cent ammonium reineckate solution. Mix and allow to stand for thirty minutes. Filter through a tared Gooch crucible and wash with water saturated with atropine metho-reineckate until free from sulphate. Wash with 3 ml of water followed by 2 ml of 95 per cent ethanol and dry over P2O5 in vacuo to constant weight. 1 g of residue = 0 5884 g C18H26O6N2. 

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