Alternative Methods of Preparation

The following alternative method of preparation is recommended. Dissolve 50 g. of purified 2 4-dinitrochlorobenzene (1) in 100 ml. of triethylene glycol (gentle warming nia be necessary alternatively, 125 ml. of warm diethylene glycol may be used) in a 600 ml. beaker and cool, with mechanical stirring, in an ice bath to 15-18°. Place 15 ml. of commercial 60-65 per cent, hydrazine solution in a small separatory funnel supported over the beaker. Add the hydrazine solution to the stirred solution in the beaker at such a rate that the temperature is maintained between 15° and 20° (20-30 minutes). When... 

In an alternative method of preparation, benzophenone is used. Prepare the Grignard reagent from 13 -5 g. of magnesium turnings as above, cool in cold water, and add a solution of 91 g. of benzophenone (Section IV,139) in 200 ml. of dry benzene at such a rate that the mixture refluxes gently. Reflux the mixture for 60 minutes, and isolate the triphenylcarbinol in the manner described above. The yield is of the same order. 

If preferred, the reaction mixture may be cooled, and the crude furil filtered through a sintered gla.ss funnel. The filtrate (containing the copper sulphate-pyridine mixture) is re-oxidised by passing oxygen tlirough it for about 15 hours. An excellent alternative method of preparation is provided by suitable adaptation of Section IV,126, Method 2. 

An alternative method of preparation involves the interaction of methylamine hydrochloride with urea to give methylurea, followed by interaction with nitrous acid as above ... 

Aromatic nucleophilic substitution of 2- or 5-halogenotltia20les (146 and 148) by sulfinate affoiMs an alternative method of preparation of sulfones (147 and 149) (Scheme 76) (170, 354-356). 

Nitrates. Iron(II) nitrate hexahydrate [14013-86-6], Fe(N03)2 6H20, is a green crystalline material prepared by dissolving iron in cold nitric acid that has a specific gravity of less than 1.034 g/cm. Use of denser, more concentrated acid leads to oxidation to iron(III). An alternative method of preparation is the reaction of iron(II) sulfate and barium or lead nitrate. The compound is very soluble in water. Crystallisation at temperatures below — 12°C affords an nonahydrate. Iron(II) nitrate is a useful reagent for the synthesis of other iron-containing compounds and is used as a catalyst for reduction reactions. 

Other fibers blended with polyesters in numerous blended fabrics requke alternative methods of preparation. Generally, the scouring and bleaching procedures used for these blends are those employed for the primary component of the blended fiber or for the component that most influences aesthetic appearance. 

The preparation of the reagents, on the other hand, is somewhat involved and requires high-speed stirring (5). Given below, therefore, is an alternate method of preparation of phenyl(trichloromethyl)mercury that requires only conventional stirring (9). The use of this compound to prepare 7,7-dichloronorcarane is also given. 

The following is an alternate method of preparation A mixture of 3-(1-piperazinyl)car-bonylmethyl-5-chloro-2(3H)-benzothiazolinone (500 mg), anhydrous potassium carbonate (400 mg), 2-hydroxyethyl bromide (300 mg) and anhydrous ethanol (20 ml) is heated while refluxing for 5 hours. The reaction mixture is concentrated under reduced pressure. The residue is extracted with chloroform. The chloroform layer is dried over magnesium... 

The following is an alternative method of preparation 1 gram 2-(7-chloropropyl)-s-tri-azolo-[4,3-al-pyridine-3-one and 5 ml saturated ammonia alcoholic solution are heated for 5 hours in a closed tube at 100°C. The contents of the tube are cooled, the ammonium chloride filtered out and the solvent is removed. There remains a residue of 0.9 grams 2-(7-aminopropyl)-s-triazolo-[4,3-al -pyridine-3-one. 

The following is an alternative method of preparation. Dissolve lOOg mercury(II) iodide and 70g potassium iodide in 100mL ammonia-free water. Add slowly, and with stirring, to a cooled solution of 160 g sodium hydroxide pellets (or 224 g potassium hydroxide)in 700 mL ammonia-free water, and dilute to 1 L with ammonia-free distilled water. Allow the precipitate to settle, preferably for a few days, before using the pale yellow supernatant liquid. 

An alternative method of preparing the saturated cyclic amines via cyclopolymerization of diallylamine or diallylammonium chloride was unsuccessful. Common free radical initiators such as 2,2 -azobisisobutyronitrile, ammonium persulfate, benzoyl peroxide were found to be ineffective. Several procedures reported in the literature were followed, and unfortunately all of them have resulted only a small amount of low molecular weight oligomers. Further research for polymerization conditions and types of initiation is still required. 

A previous method [1] of preparing 3,3-dimethylbutyne by dehydrochlorination of the title compound in a sodium hydroxide melt is difficult to control and hazardous on the large scale. Use of potassium ferf-butoxide as base in DMSO is a high-yielding, safe and convenient alternative method of preparation of the alkyne [2], See Dimethyl sulfoxide Metal alkoxides See other HALOALKANES... 

In an alternative method of preparing m/vo-dihydroxyanthraquinonedisulfonic acid by heating the title compound with oleum to effect simultaneous hydrolysis, denitration and sulfonation of the nucleus, there is the possibility of formation of methyl nitrate from the scission fragments. 

In Report no. 16 on fluorophosphonates to the Ministry of Supply,3 we gave an account of a very useful alternative method of preparation. The method consisted in treating an amine with the calculated quantity of phosphorus oxychloride in ethereal solution P0C13+4NH2.R = P0C1(NH.R)2 + 2.R-NH3C1. (a)... 

A very reactive form of a finely divided metal is a so-called Rieke powder [79]. These materials are produced as fine powders by chemical precipitation during the reduction of various metal halides ivith potassium metal in refluxing tetrahydrofuran. Obviously this is a potentially hazardous laboratory procedure and ultrasound has provided an alternative method of preparation of these extremely valuable reagents [80]. The sonochemical technique involves the reduction of metal halides with lithium in TH F at room temperature in a cleaning bath and gives rise to metal powders that have reactivities comparable to those of Rieke powders. Thus powders of Zn, Mg, Cr, Cu, Ni, Pd, Co and Pb were obtained in less than 40 min by this ultrasonic method compared with reaction times of 8 h using the experimentally more difScult Rieke method (Tab. 3.1). 

Alternative methods of preparation of anhydrous salt involve the reduction of iron(Ill) fluoride with hydrogen or by passing fluorine gas over anhydrous iron(Il) chloride in the cold ... 

The ability to provide highly functionalized reagents, such as unsaturated silanes and vinyl boronates, starting from terminal olefins is one of the most attractive attributes of CM, particularly when traditional methods for the preparation of such compounds are not synthetically straightforward. Therefore, significant research has been undertaken to determine the broad-spectrum chemoselectivity of olefin metathesis catalysts. In many cases, the use of a CM protocol in reagent synthesis is completely orthogonal to alternative methods of preparation. 

A procedure for the preparation of o-tolualdehyde from o-toluanilide by the Sonn-Miiller method has been published in Organic Syntheses. In addition to the alternative methods of preparation listed there, o-tolualdehyde has been prepared from o-xylyl bromide and hexamethylenetetramine, by the Stephen reduction of o-tolunitrile, and by the procedure of the present preparation. ... 

An alternative method of preparation consists in dissolving the aniline in 4 times its weight of glacial acetic acid in a beaker, and running in slowly from a tap funnel, while the solution is well stirred with a mechanical stirrer, the theoretical amount of bromine dissolved in twice its volume of glacial acetic acid. The beaker should be cooled in ice during the addition as the reaction is exothermic. The final product (a pasty mass) should be coloured yellow by the addition of a little more bromine if necessary. Pour into excess of water, filter at the pump, wash well with water, press thoroughly, and dry. The yield of tribromo-aniline, m.p. 119-120°, is quantitative. Recrystallise a small portion from methylated (or rectified) spirit m.p. 120°. 

Vanadyl Dibromide, VOBr2, is obtained by passing bromine vapour or, preferably, a mixture of sulphur bromide, SaBra, and bromine over a mixture of vanadium pentoxide and sulphur at a red heat the product is heated in vacuo at 240° C., whereupon the vanadyl dibromide is obtained as a yellow powder.8 An alternative method of preparation consists in heating vanadium oxytribromide, VOBr3, to 180° C.9 Vanadyl dibromide is no doubt present in the blue solution which results when hypovanadic oxide, VOa, is dissolved in hydrobromic acid. 

Alternative methods of preparing the starting acids can be used, but are generally less convenient. Benzo[6 ]thiophene derivatives were prepared from 2-methyl-3-(2 -thenoyl)propionic acid, which was obtained either by reacting 2-thienylmagnesium iodide with methylsuccinic anhydride, or by coupling 2-bromoacetylthiophene with the sodium salt of diethyl methylmalonate (45JA1645). 

Benzenol and the 2-, 3-, and 4-methylbenzenols (cresols) can be isolated from coal tar (Section 22-11). Benzenol itself is used commercially in such large quantities that alternate methods of preparation are necessary and most of these start with benzene or alkylbenzenes. Direct oxidation of benzene is not satisfactory because benzenol is oxidized more readily than is benzene. 

Alternate methods of preparing aqueous extracts, especially the use of a Cl8 Sep-Pak cartridge, are described in unit fi.i. 

An alternative method of preparing highly active zinc hexacyano-cobaltate catalyst involved the use of hexacyanocobaltic acid prepared by passing the potassium salt through cationic exchange resin (Rohm and Haas A-15). 

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