Uses of phosphorus

This preparation illustrates the use of phosphorus pentachloride for the preparation of acyl chlorides in this case no difficulty is experienced in separating the 3,5-dinitrobenzoyl chloride from the phosphorus oxychloride formed simultaneously (c/. p. 240), because the former is readily isolated as a crystalline... 

Treatment of a-thiocyanatoketones at low temperature with dry hydrogen chloride in ether solution gives satisfactory yields of 2-chloro-thiazole derivatives (188). The use of phosphorus pentachloride leads to the same results, but in this case chlorination can also occur at the 5-position (Scheme 97) (18, 68). 

Properties and Essential Information for S afe Handling and Use of Phosphorus Ouychloride, Chemical Manufacturers Association Chemical Safety Data Sheet SD-26, Washington, D.C., 1948. 

These formulae explain the scission products of the two alkaloids and the conversion of evodiamine into rutaecarpine, and were accepted by Asahina. A partial synthesis of rutaecarpine was effected by Asahina, Irie and Ohta, who prepared the o-nitrobenzoyl derivative of 3-)3-amino-ethylindole-2-carboxylic acid, and reduced this to the corresponding amine (partial formula I), which on warming with phosphorus oxychloride in carbon tetrachloride solution furnished rutaecarpine. This synthesis was completed in 1928 by the same authors by the preparation of 3-)S-amino-ethylindole-2-carboxylic acid by the action of alcoholic potassium hydroxide on 2-keto-2 3 4 5-tetrahydro-3-carboline. An equally simple synthesis was effected almost simultaneously by Asahina, Manske and Robinson, who condensed methyl anthranilate with 2-keto-2 3 4 5-tetrahydro-3-carboline (for notation, see p. 492) by the use of phosphorus trichloride (see partial formulae II). Ohta has also synthesised rutaecarpine by heating a mixture of 2-keto-2 3 4 5-tetrahydrocarboline with isatoic anhydride at 195° for 20 minutes. 

QuinoxaIin-2-oncs are readily converted into the corresponding 2-chloroquinoxalines by treatment with phosphoryl chloride in the case of the highly insoluble 2,3-diones chlorination is effected conveniently with a mixture of phosphoryl chloride and dimethyl-aniline. The use of phosphorus pcntachloride may lead to side reactions, for example, quinoxalin-2-one (70) is converted into 2,3-... 

The product is then dried in a high vacuum with the use of phosphorus pentoxide (P2O5). 

Previous syntheses of terminal alkynes from aldehydes employed Wittig methodology with phosphonium ylides and phosphonates. 6 7 The DuPont procedure circumvents the use of phosphorus compounds by using lithiated dichloromethane as the source of the terminal carbon. The intermediate lithioalkyne 4 can be quenched with water to provide the terminal alkyne or with various electrophiles, as in the present case, to yield propargylic alcohols, alkynylsilanes, or internal alkynes. Enantioenriched terminal alkynylcarbinols can also be prepared from allylic alcohols by Sharpless epoxidation and subsequent basic elimination of the derived chloro- or bromomethyl epoxide (eq 5). A related method entails Sharpless asymmetric dihydroxylation of an allylic chloride and base treatment of the acetonide derivative.8 In these approaches the product and starting material contain the same number of carbons. 

It can be fundamentally stated that surfactants covering nearly all tasks can be derived from phosphoric acid. It is often only the somewhat higher price blocking the same widespread use of phosphorus-containing surfactants compared to the output of mass surfactants. The fraction of phosphorus-containing surfactants reaches about 1 % of total surfactant production. 

Wetting is an absolute condition for detergency. However, wetting plays an important role in other applications as well. A special case is the penetration of fluids in porous material. That may be a bundle of fibers in the dying process or the stone matrix in enhanced oil recovery. One of the steps of lubrication is wetting of surfaces by lubricant liquids. Because other conditions must also be considered, the use of phosphorus-containing surfactants is beneficial. 

Hall and Steuck polymerized 2 with a variety of Lewis and Bronsted acids or oxonium salts. The best conditions for the polymerization proved to be the use of phosphorus pentafluoride in methylene chloride solution at -78 °C. Yields of methanol-insoluble polymers ranging from 68 to 84% were obtained with inherent viscosities of 0.26—0.33 dl/g. Lower or higher temperatures gave lower yields. Tetra-hydrofuran as solvent at —78 °C gave 68-92% yields of materials having inherent viscosities of 0.12-0.14 dl/g. No incorporation of tetrahydrofuran into the polymer occurred. 

Tetrahydrofurfuryl bromide has been obtained in low yields by the action of hydrobromic acid, or of phosphorus tribromide, on the corresponding alcohol.1 The yield is improved markedly by use of phosphorus tribromide and pyridine.2 3 The bromide has also been prepared by the action of potassium hydroxide on 4,5-dibromopentanol-l.4... 

The deoxygenation of some penicillin and cephalosporin sulphoxides has been accomplished by the use of phosphorus pentasulphide.53 The reactive species responsible for deoxygenation was not identified. A particularly mild method for reducing sulphoxides to sulphides involves the reaction of the sulphoxide with 2-chloro-l,3,2-benzodioxaphosphole at room temperature.536 Yields in excess of 80% were reported. 

The use of phosphorus compounds as flame retardants has been reviewed by Lyons and others (1, 2, 3, 4 5). The mechanism of the action of this element is generally accepted to involve decomposition to produce acids which function as char promoters. Phosphorus compounds are particularly effective flame retardants for polyesters where they function to increase the char yields. 

The first question is to decide between halogen-free and halogen-containing systems. The second concerns the possible use of phosphorus additives. Figure 3.43 schematizes some possible routes in each case. 

The choice of probe molecule for acidity determination is largely dictated by the sensitivity of the nuclei, and the high sensitivity of P nuclei has been exploited to quantify acidity in zeolites. The use of phosphorus containing bases as probe molecules to measure solid acidity circumvents insensitivity problems associated with (1.1% abundance) and N (0.4% abundance) in bases such as ammonia. 

The author hopes that this chapter has convinced the readers of the value of homogeneous catalysis for the synthesis of organophosphorus compounds and for organo-heteroatom compounds in a broader sense. Hydrosilylation and hydroboration are indispensable modern synthetic reactions in this category. The H-P addition reactions herein described joins them as a third member. Although this chapter does not cover, the addition reactions of the S-P and Se-P bonds in thiophosphates [39] and selenophosphates [40] to alkynes also proceed in the presence of transition metal catalysts. In view of the wide use of phosphorus compounds, the new procedures will find practical applications. 

Diazinones may be converted into chlorodiazines by the use of phosphorus oxychloride, just as... 

A more efficient method for converting the oxide (258) to 2-azaquinolizinium bromide is by refluxing it in phosphorus tribromide (Scheme 129) <67JCS(C)2391>. Deoxygenation by use of phosphorus trichloride or tribromide proved effective (7lJCS(C)86l) with a number of 2-azaquinolizinium 2-oxides substituted in positions 1 and 3, although the 1-methyl oxide offered some resistance. 

Other examples of the use of phosphorus-containing reagents for the synthesis of deoxyhalogeno sugars, by way of Arbusov-type reactions, are described in Section 11,5 (see p. 278). 

The reaction of phosphorus tribromide with the alcohol above has been reported by Marvel to give the analogous bromide. The use of phosphorus trichloride did not yield the chloride [80]. 

In our study of the fluorination of coordinated chlorophosphine ligands (23), we started out with tetrakis(trichlorophosphine)nickel-(0), which could previously be converted into tetrakis(trifluorophosphine)nickel-(0) by displacement of the coordinated phosphorus trichloride with excess phosphorus trifluoride in a sealed tube (32). The limitations of this method, requiring the use of phosphorus trifluoride, a low boiling gas, under pressure, and involving the mechanical separation of the fluorophosphine complex from phosphorus trichloride, are obvious, and the yield was low. A straightforward method for the synthesis of this interesting compound was found in the fluorination of the coordinated phosphorus trichloride with potassium fluorosulfinate ... 

The only alkyl group reported as reductively removed is the di-phenylmethyl substituent from N3 in compound 165.153 Deoxygenation of N-oxides can be done thermally (heating in toluene with oxygen transfer to solvent) for compounds of type 166,44 or more commonly by use of phosphorus derivatives, as described for compounds 32, 33,45 166,44 and 167.61 Halogens can be reductively removed from [l,2,3]triazolo-[4,5-6]pyridines 160,146 168,220 and 169,142 and from pentachloro derivative 164, giving dichloro compound 170.208 Removal of thiol groups by reduction... 

A further illustration of the reaction of carbanionic species with o-hydroxybenzaldehydes is provided by the use of phosphorus ylides in coumarin synthesis. Thus, ethoxycarbonyl-methylenetriphenylphosphorane affords simple coumarins via the ester (380 R = H), whilst with o-hydroxyacetophenone a 4-methylcoumarin results (381 R = Me) (77S464), and 4-methylsulfinylmethylcoumarin (381 R = CH2SOMe) is obtained from o-hydroxy-a>-methylsulfinylacetophenone (Scheme 120) (72JHC175). 

Conversion of the phenoxypropanoic acid into the acid chloride enhances the ease of cyclization and the use of phosphorus pentachloride and aluminum chloride provides an example of this technique (51JA4205). The formation of 3-aminochroman-4-one has been achieved in this way starting from 2-amino-3-phenoxypropanoic acid (76TL271). Cyclization of the phenoxyethanoic acid shown in Scheme 234 occurs on reaction with sodium methoxide to give the chroman-3-one (63JCS5322). 

The use of phosphorus compounds has two advantages the reactions are performed in homogeneous mixtures and secondly, phosphorus derivatives are milder dehalogenation agents and, therefore, react with a better regioselectivity compared with most metallic agents, e.g. zinc.112... 

---