Extraction crude nitrogen

This system of analysis divides the food into six fractions moisture, ash, crude protein, ether extract, crude fibre and nitrogen-free extractives. 

When the smn of the amounts of moistrue, ash, crude protein, ether extract and crude fibre (expressed in g/kg) is subtracted from 1000, the difference is designated the nitrogen-free extractives. The nitrogen-free extractives fraction is a heterogeneous mixture of all those components not determined in the other fractions. The crude fibre fraction contains cellulose, hgnin and hemiceUuloses, but not necessarily the whole... 

The nitrogen-free extract comprises nonfibrous soluble carbohydrates (starch, monosaccharides, and disaccharides). In the proximate analysis, the NFE is calculated by difference (NFE = 100 — % moisture — % crude protein — % fat or ether extract — % crude fiber — % ash). 

Add, with stirring, a solution of 6 8 g. of the fiis-diazo ketone in 100 ml. of warm dioxan to a suspension of 7 0 g. of freshly precipitated silver oxide in 250 ml. of water containing 11 g. of sodium thiosulphate at 75°. A brisk evolution of nitrogen occurs after 1 5 hours at 75°, filter the liquid from the black silver residue. Acidify the almost colourless filtrate with nitric acid and extract the gelatinous precipitate with ether. Evaporate the dried ethereal extract the residue of crude decane-1 10-dicarboxylic acid weighs 4 -5 g. and melts at 116-117°. RecrystaUisation from 20 per cent, aqueous acetic acid raises the m.p. to 127-128°. 

Ref. 29. Estimated by difference 100 — (protein + oil + ash + crude fiber) = nitrogen-free extract. 

Hydrocortisone Crude hydrocortisone bissemicarbazone (50 g) is dissolved at 20° in 2.5 liters of 2.4 N hydrochloric acid under a nitrogen atmosphere. The solution is cooled to 5°, and then a solution of 25 g of sodium nitrite in 250 ml of water is added over a 15 min period, the temperature being maintained at 5 + 1°. The reaction mixture is stirred for an additional 30 min at 5°, then treated with a solution of 150 g of urea in 250 ml of water over a 15 min period and finally neutralized below 15° with 20% sodium hydroxide. The mixture is extracted several times with chloroform and the solvent is evaporated under reduced pressure to give 33 g of crude hydrocortisone, mp 197-203°. Crystallization from acetone-Darco gives 26.4 g (69.5%) of pure hydrocortisone mp 216-221° [oc]d 151° (Diox). 

Methoxy-cis-19-norpregna-l,3,5(10),17(20)-tetraene A solution of 31 g (109 mmolesi of estrone methyl ether in 600 ml of benzene is added rapidly to a solution of 469 mmoles of ethylidenetriphenylphosphorane in 1.2 liters of DMSO. After heating under nitrogen at 60° overnight, the reaction is cooled, poured into ice water, and extracted with three portions of hexane, backwashed with three portions of water and the hexane removed. The crude product, dissolved in petroleum ether (bp, 30-60°), is filtered through 225 g of alumina (activity I). The residue from the eluate consists of 95 % cis- and 5 % tran5-isomers, as determined by vpc analysis. After recrystallization from ether-methanol, 26.3 g (82%) of cw-isomer is obtained mp 76.5-77.5° [a]o 60°. 

The crude diol (47)(3.8 g) is dissolved in 160 ml of methanol, mixed with 4 g of potassium hydroxide in 10 ml of water and 20 ml of methanol, and warmed under nitrogen for 5 min. Acetic acid (4 ml) is added and the solution is poured into an aqueous solution of sodium chloride. The product is extracted 3 times with ethyl acetate and the extracts are washed with 10% sodium bicarbonate and then with water. The solvent is removed by distillation and the residue is recrystallized from acetone-petroleum ether to give 1.85 g of (48) mp 275-277°. 

A 1.5 to 2 M solution of methylsulfinyl carbanion in dimethyl sulfoxide is prepared under nitrogen as above from sodium hydride and dry dimethyl sulfoxide. An equal volume of dry tetrahydrofuran is added and the solution is cooled in an ice bath during the addition, with stirring, of the ester (0.5 equivalent for each 1 equivalent of carbanion neat if liquid, or dissolved in dry tetrahydrofuran if solid) over a period of several minutes. The ice bath is removed and stirring is continued for 30 minutes. The reaction mixture is then poured into three times its volume of water, acidified with aqueous hydrochloric acid to a pH of 3-4 (pH paper), and thoroughly extracted with chloroform. The combined extracts are washed three times with water, dried over anhydrous sodium sulfate, and evaporated to yield the jS-ketosulfoxide as a white or pale yellow crystalline solid. The crude product is triturated with cold ether or isopropyl ether and filtered to give the product in a good state of purity. 

D) 1-p-Chlorobenzoyl-2-Methyl-S-Methoxy-3-lndolylacetic Acid A mixture of 1 g ester and 0.1 g powdered porous plate is heated in an oil bath at 210°C with magnetic stirring under a blanket of nitrogen for about 2 hours. No intensification of color (pale yellow) occurs during this period. After cooling under nitrogen, the product is dissolved in benzene and ether, filtered, and extracted with bicarbonate. The aqueous solution is filtered with suction to remove ether, neutralized with acetic acid, and then acidified weakly with dilute hydrochloric acid. The crude product (0.4 g, 47%) is recrystallized from aqueous ethanol and dried in vacuo at 65°C MP 151°C. 

The mixture was then allowed to warm to room temperature in a nitrogen atmosphere during which process the ammonia evaporated. The reaction mixture was then acidified with 1 N aqueous hydrochloric acid, and the organic constituents extracted with ethyl acetate. The ethyl acetateextracts were combined, washed with water and dried. Evaporation of the ethyl acetate under reduced pressure yielded 1.4 g of crude dl-trans-3-(r,r-dimethylheptyl)-6,6a, 7,8,10,10a -hexahydro-1 -hydroxy-6,6-dimethyl-9H-dibenzo(b/J] pyran-9-one. The... 

A solution of 3.7 g (12 mmol) of the pure (l R)-diastereomer 6 is stirred under nitrogen in 15 mL of iodomethane and 5 mL of dry DMSO for 36 h. The excess iodomethanc is evaporated leaving a viscous red oil which is heated under reflux in 25 mL of 2N KOI for 5 h. After cooling, the amino alcohol is removed from the aqueous phase by extraction with Et20. The alkaline aqueous layer is acidified with 12 N HC1 and extracted with Ei,0. The crude product is recrystallized from benzene/petroleum ether to give enantiomer-ically pure (R)-2-hydroxy-2-phenylpropanoic acid [(-)-(R)-atrolaclic acid] (7) yield 1.4 g (71%) mp U5-116X [x]25 - 38.4 (< = 2.5, EtOH). 

A mixture of 1.4 g (10 mmol) of 4-chlorobenzaldehyde and 0.71 g (5 mol %) of the chiral polymer E is stirred in 10 mL of dry toluene for 15 h, under a dry nitrogen atmosphere, to form the Schiff base. After cooling to 0lC, 15 mL (15 mmol) of 1 M diethyl/inc in hexane is added and the mixture is stirred for a further 24 h at O C. 1 N HC1 is then added dropwise at O C, and the chiral polymer is removed by filtration. The polymer is washed several times with 11,0 and Et,0. The aqueous layer is separated and extracted with Et20. The combined organic layer is dried over MgS04 and concentrated under reduced pressure. The crude product is purified by column chromatography (silica gel, CHC1,) yield 1.61 g (95 %) 99 % ee [a]2,0 —23.9 (r = 4.93, benzene). 

A solution of 1.0 mmol of 2-acetyl alkenoate in 2.5 mL of CH2C1, is added slowly to a solution of 4.0 mmol of titanium(IV) chloride in 7.5 mL of CH-CL under an atmosphere of nitrogen at — 78 °C. The mixture instantaneously turns deep red. and is stirred at — 78 °C before being quenched by the addition of 5 mL of sat. aq potassium carbonate. The mixture is then partitioned between 10 mL of bt20 and 10 mL of water. The aqueous phase is extracted with three 10-mL portions of Et2(), and the extracts are combined, washed with 10 mL of brine, and dried over anhyd potassium carbonate. Concentration under reduced pressure gives the crude product. Product analysis is by capillary GC. 

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