Acetone Ascorbic acid

Acetone, (reduction with) ascorbic acid, citrate, CE, CN , 2,3-dimercaptopropan-I-oI, EDTA, formate, E, 8CN , 80 , tartrate, thiosemicarbazide, thiourea, triethanolamine CE, EDTA, F , 8CN , tartrate, thiourea, triethanolamine Citrate, CN , 8CN , tartrate, thiourea Citrate, EDTA, F , oxalate, tartrate, tiron... 

Most current industrial vitamin C production is based on the efficient second synthesis developed by Reichstein and Grbssner in 1934 (15). Various attempts to develop a superior, more economical L-ascorbic acid process have been reported since 1934. These approaches, which have met with htde success, ate summarized in Crawford s comprehensive review (46). Currently, all chemical syntheses of vitamin C involve modifications of the Reichstein and Grbssner approach (Fig. 5). In the first step, D-glucose (4) is catalytically (Ni-catalyst) hydrogenated to D-sorbitol (20). Oxidation to L-sotbose (21) occurs microhiologicaRy with The isolated L-sotbose is reacted with acetone and sulfuric acid to yield 2,3 4,6 diacetone-L-sorbose,... 

DAG is treated with ethanol and hydrochloric acid in the presence of inert solvent, eg, chlorinated solvents, hydrocarbons, ketones, etc. The L-ascorbic acid precipitates from the mixture as it forms, minimising its decomposition (69). Cmde L-ascorbic acid is isolated through filtration and purified by recrystallization from water. The pure L-ascorbic acid is isolated, washed with ethanol, and dried. The mother Hquor from the recrystallization step is treated in the usual manner to recover the L-ascorbic acid and ethanol contained in it. The cmde L-ascorbic acid mother Hquor contains solvents and acetone Hberated in the DAG hydrolysis. The solvents are recovered by fractional distillation and recycled. Many solvent systems have been reported for the acid-catalyzed conversion of DAG to L-ascorbic acid (46). Rearrangement solvent systems are used which contain only the necessary amount of water required to give >80% yields of high purity cmde L-ascorbic acid (70). 

The following polyvitamin prepai ations were analyzed Kal tsid (OAO Comfort Plus , Russia), Asvitol (OAO INC Marbiofarm , Russia), Pikovit (KRKA, d.d. The New Place, Slovenia), Yeast with vitamin C (000 EKKO Plus , Russia). Chromatographic experiment has been carried out using Silufol UV-254 (Kavalier, Czech Republic) and acetone - ethyl acetate - acetic acid - ethanol (3 5 1 1) - CTAB (2T0 M) as a mobile phase mixture. The linearity calibration plot, built in coordinate S = f (IgqAC), is valid in the interval 5-25 p.g. Correctness of the determination has been checked by photometry. The obtained results for the ascorbic acid determination are presented below. 

Colorimetric procedures used In steroid assays are often subject to drug Interference. In the determination of 17-Ketosterolds by the Zimmerman reaction, drugs with the 17-Keto basic structure such as ascorbic acid, morphine and reserplne will cause Increased values. In the determination of 17,21 -dlhydroxysterolds by the Porter-Sllber reaction the dlhydroxy-acetone chain Is the reactive unit. Drugs like meprobamate, chloral hydrate, chloropromazlne and potassium Iodide will Interfere with this reaction and cause elevated values. In the colorimetric determination of vanlllylmandellc acid (VMA) by a dlazo reaction, drugs like methocarbamol and methyl dopa cause... 

In the year 1994, T. Takao et al. published a staining reaction to identify radicalscavenging activity [21]. Takao et al. used the compound l,l-diphenyl-2-picrylhydra-zyl (DPPH), which changes its color, in the presence of antioxidants such as ascorbic acid or rutin, from blue-purple to colorless or yellow. Forty mg of DPPH has to be solved in 20 ml of acetone or methanol. The reaction is complete immediately. 

The variation in the antiscorbutic activity displayed by the various analogs of L-ascorbic acid makes it abundantly clear that the activity is dependent upon the stereochemical configuration of the molecule as a whole, and it would appear that the more closely the structure of a particular analog approaches that of the natural Vitamin C the greater will be the antiscorbutic power. Support for this view is illustrated by 6-desoxy-L-ascorbic acid which is obtained from L-sorbose.2 -80 Condensation of L-sorbose with acetone gives a mixture of 2,3-isopropylidene-L-sorbose (LII) and the diisopropylidene derivative. Treatment of LII with p-toluenesulfonyl chloride yields l,6-ditosyl-2,3-isopropylidene-L-sorbose (LIII). The greater reactivity of the tosyl group at C6 enables... 

Hg Acetone, (reduction with) ascorbic acid, citrate, Cl-, CN-, 2,3-dimercaptopropan-l-ol, EDTA,... 

A remarkably selective phosphorylation at HO-3 in L-ascorbic acid and its 5,6-O-isopropylidene derivative has been achieved with phosphoryl chloride in aqueous pyridine204 the use of acetone-pyridine as the solvent led to a much less selective reaction. 

The reaction of cephalosporanic acid (1598) and cyclopenteno(6)pyri-dine in a 3 1 mixture of water and acetone in the presence of potassium iodide and ascorbic acid at 66-68°C for 4 hr gave the pyridiniumceph-3-ene-4-carboxylate derivative (1599) in 14% yield (84GEP3316796). 

To evaluate the presence of possible interferences, the following metabolites were tested at their physiological concentration bilirubin, sucrose, cholesterol, triglycerides, acetone, urea, uric acid, citric acid, L-ascorbic acid, citrate, pyruvate, haemoglobin, y-globulin, sodium pyruvate, NaCl, KC1, Ca2+ and EDTA. Urea, uric acid, L-ascorbic acid, NaCl, KC1 and Ca2+ generated a slight interference. 

Dark green vegetables Blanch leaves in boiling water. Homogenize with water containing 0.5% ascorbic acid. Extract an aliquot of the resultant mixture with acetone/ petroleum ether (3 2) containing 0.5% BHT by shaking for 10 min. Reextract until colorless (3 extractions). Saponify (ambient) the combined solvent extracts. Vydac 201 TP Clg 5 /zm 250 X 4.6 mm MeOH/CH,C1,/ H,0, 80 15.2 4.8 A ]-trans-, 9-cis-, 13-cis-/3-carotene, all-trans-a-carotene Vis 450 mn 177... 

The reaction of L-sorbose with acetone, a step in the synthesis of L-ascorbic acid (vitamin C), takes place in acetone solution [Eq. (41)] (361). 

Other ketones and aldehydes have been used for preparing protected derivatives of L-sorbose that are structurally analogous to 26. These include cyclohexanone,113-115 formaldehyde,81,118 acetone,81, 118,117 benzaldehyde,81,118 and 1-methylcyclohexanone.115 The resulting acetals have been converted into L-ascorbic acid. 

The Reichstein-Griissner process, developed in 1934, takes in all five chemical steps (hydrogenation, fermentative oxidation, acetonization, oxidation, and hydroly-sis/rearrangement) (Table 20.3). Over the course of the whole synthesis there are 17-20 different downstream processing steps, six solid-handling steps, and at least seven different solvent systems to handle. The overall yield is about 55%, and overall cycle time is around three days. Such values clearly suggest possible improvement in the process towards ascorbic acid. 

The 5,6-O-isopropylidene acetal (152) of L-ascorbic acid has been prepared,340 and von Schuching and Frye341 prepared the corresponding cyclohexylidene acetal. These compounds were found to be more resistant than L-ascorbic acid toward oxidation, and the parent acid can be readily regenerated by acid hydrolysis. The derivative was used in the synthesis of 14C-labeled vitamin C. The C-2 and C-3 enols of L-ascorbic acid or its acetone derivative (152) can be readily methylated with diazomethane, yielding the corresponding dimethoxy analogues. 

Selective alkylation of 5,6-O-isopropylidene-L-ascorbic acid (152) at 0-3 has been performed with K2C03-acetone-alkyl halides. With an excess of alkyl halide, the 2,3-di-O-alkylated derivatives could be obtained, but by stepwise alkylation different alkyl moieties could be introduced at 0-3 and 0-2.349... 

Fig. 8.29 Industrial, chemical synthesis of L-ascorbic acid. Experimental conditions have been taken from [145]. Structures (except those of the acetone derivatives) are in open-chain Fischer projection to make the...

An oxidative route to (SJ-glycerolic acid would require L-mannitol, which is, however, a rare and expensive compound. L-Ascorbic acid (ASA), in contrast, is a readily available commodity that has been converted into (S)-glycerolic acid via acetone protection and a two-step oxidation (Fig. 8.33) [179]. 

Solvents, e.g., ethanol, acetone Cells, e.g., bakers yeast, brewers yeast Crude cellular extracts, e.g., yeast extract Organic acids, e.g., citric acid, lactic acid Vitamins and amino acids, e.g., lysine, ascorbic acid Gums and polymers, e.g., xanthan, geUan Antibiotics, e.g., peniciUins, rifampicin... 

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