NITROGEN.182 SODIUM FLUORIDE

The number of fluorine equivalents (to toluene) was varied the gas and liquid flow velocities were kept constant to maintain the same flow pattern for all experiments. Liquid products were collected in an ice-cooled roimd-bottomed glass flask containing sodium fluoride to trap the hydrogen fluoride. The flask is connected to a cooling condenser to recover the solvent. Samples were typically collected for 1 h. Waste gases were scrubbed in aqueous 15% potassium hydroxide solution. Samples were degassed with nitrogen and filtered before analysis. 

The apparatus consists of a 2-1., three-necked, round-bottomed flask equipped with a mechanical stirrer, a pressure-equalized dropping funnel through which dry nitrogen can be added, and a reflux condenser, and is to be maintained at 0°. The outlet tube on the reflux condenser leads to a large U-tube trap, fitted with stopcocks on both sides, and immersed in a Dry Ice-isopropyl alcohol bath. The U-trap vents to a mineral oil bubbler. (See Fig. 17.) Sodium fluoride, 454 g. (10.8 mols) is added to the flask followed by approximately 1200 ml. of tetramethylene sulfone. The system is then flushed thor-... 

AMMONIUM CHLORIDE NITRIC OXIDE NITROGEN DIOXIDE HYDRAZINE NITROUS OXIDE SODIUM CYANIDE SODIUM FLUORIDE SODIUM HYDROXIDE NICKEL... 

Nitro substituents and heterocyclic nitrogen influence not only the yield of fluorodediazoniation but also the rate of decomposition which, in these cases, is too high to perform the reaction on a multigram scale. Some explosions have been reported. Thus, the decomposition of nitro-substituted or heterocyclic diazonium tetrafluoroborates is usually controlled by three-to fivefold dilution of these substrates in inert solids, such as acid-washed sand,113 218 Kiesel-guhr,3 sodium carbonate,3 barium sulfate,217 sodium fluoride,216 or sodium tetrafluoroborate.3 This modified technique has been generalized to the decomposition of all kinds of diazonium tetrafluoroborates under safe conditions, even on rather large scales. 

Refs l)Beil 3, 2 2)J.Glattfeld D.Mac-millan, J ACS 56,2481 2( 1934) (Preparation of aldonic and saccharic acid amines in liquid ammonia) 3)G.V.Caesar M.Gold-frank, J ACS 68,372-5(1946)(Nitration of starches with nitrogen pentoxide in presence of sodium fluoride) 4)Karrer( 1950), 325 ... 

Meyer H.Wehrli, Helv 20, 353(1937) CA 31, 5807(1937) 5)M.L.Wolfrom et al, JACS 65, 2084(1943) 6)M.L.Wolfrom et al, Ohio State Univ Final Rept, Project 459, Columbus, Ohio(Jan 1953)pp 1,3 34 Nitrated Deacetylated Chitine A wh flocculent ppt contg 11=6 to 11,9% nitrate N(as detd by DuPont nitrometer obtd by Wolfrom et al(Ref 3) by nitrating deacetylated chitin with 100% HNOj. The nitrated product represented the combined nitrate salt nitrate ester of deacetylated chitin. This substance contd one nitric acid salt unit per anhydro-o-glucosamine unit and 1.60-1.65 nitrate ester unit per anhydro-o-glucosamine anhydro -N-acetyl-D -glucosammine units. Attempts to nitrate deacetylated chitin by means of nitrogen pent oxide, in a non-aqueous medium y in the presence of sodium fluoride, by the method of Caesar(Ref 2) were unsuccessful mainly because of occlusion of NaF in the nitrated products(Ref 3)... 

Difluorodiazene contaminated with SiF4 and NF3 is held at —195°C. This mixture is passed through a sodium fluoride trap to remove SiF4 by the formation of Na2SiF6. Difluorodiazene may be separated from nitrogen trifluoride by gas chromatography with the use of a 25-ft. X 0.25-in. aluminum or copper column... 

Aluminum fluoride is made by heating ammonium hexafluoroaluminate to red heat in a stream of nitrogen by the action of fluorine or hydrogen fluoride gas on aluminum trihydrate at high temperatures, followed by calcining the hydrate formed by fusing cryolite or sodium fluoride with aluminum sulfate or by a reaction of fluosilicic acid on aluminum hydrate (HSDB 1995). 

Tetraalkoxy Tellurium Difluorides1 The required amount (0.16 mol) of alkanol and 90 g (2.1 mol) of dry sodium fluoride are placed in a 600-ml reaction tube. The tube is cooled in liquid nitrogen, evacuated to 0.001 torr, and 8.6 g (35.6 mmol) of tellurium hexafluoride are condensed into the tube, which is then sealed. The tube is allowed to warm to 20", then heated at 90° for 9 days, cooled, and opened. The mixture is extracted with chloroform, the extract is evaporated, and the residue is distilled under vacuum. 

The affinity of drags to proteins can be pH dependent. Hence, it is necessary to control the pH of the plasma prior. The pH value can be adjusted to an appropriate standard value (pH 7.4) by introducing carbon oxide or nitrogen gas. Also the stability of the drug in the matrix (e.g. plasma) should be verified prior to the assay. For instable compounds the degradation (e.g. esterase) can be avoided by addition of appropriate inhibitor (e.g. sodium fluoride). 

This loses one of the carboxylates on heating in the presence of toluene-sulfonic acid to afford the (B-ketoester (82). Reaction of this intermediate with ethylorthoformate then adds a carbon atom to the activated methylene. Heating that compound with cyclopropylamine in effect exchanges the ethoxy group with the amine to afford enamine (84). Treatment 84 with sodium fluoride leads to displacement of one of the ring fluoro groups by the basic nitrogen on the side chain. This step concludes the formation... 

The reaction mixture is slowly heated. Between 80 and 100° inner temperature a liquid product starts to distill. The colorless reaction mixture gradually turns dark black. Distillation is continued until the pot temperature reaches 250°. Material distilling between 60 and 75° (mainly 60 to 65°) is collected. The yield is 35 to 38 g. (74 to 81%). The product is redistilled over a small amount of sodium fluoride through a 10-in. glass helix-packed column in a nitrogen atmosphere at atmospheric pressure b.p. 61 to 62°. (The checkers, working on half this scale report a yield of 76%, b.p. 61 to 62°.) Dimethyltrifluorophosphorane may be stored in a Teflon or stainless-steel container. 

Nitrogen fluoride, cis (FNNF) Nitrogen fluoride, trans (FNNF) Sodiun fluoride, ion (NaFg ) Sodium fluoride ((NaF)g)... 

The conversion of the sulfonyl chloride to the sulfonyl fluoride was carried out as follows. The sulfonyl chloride was removed from the filter by washing it with alcohol-free chloroform into a 5-ml round-bottom flask. The chloroform was then removed and 0.5 ml of acetonitrile and 167 mg of dry powdered sodium fluoride was added. The resulting mixture was magnetically stirred at 90°C for 6 hr, 2 ml of alcohol-free chloroform was then added and the mixture was filtered into a sublimation apparatus and the solvent was removed in a stream of nitrogen. The product sublimed readily at 45°C (0.3 mm) and could then be recrystallized from benzene-cyclohexane to yield crystals with m.p. 90-92°C. 

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