Preparation of Phosphorus Compounds

Preparation of Intermediate Compound 2-Methyl-3-o-Tolyl-6-Sulfamyl-7-Chloro-4(3H)-Quinazoiinone Set up a 5-liter 3-necked flask fitted with a stirrer, condenser and a drying tube. To a stirred mixture of 100 g (0.342 mol) of powdered 4-chloro-5-sulfamyl-N-acetylanthranilic acid, 40.2 g (0.376 mol) of o-toluidine and 2.0 liters of dry toluene was added dropwise, over a period of 15 minutes, 21.7 ml (34.1 g) (0.248 mol) of phosphorus trichloride. The mixture was then refluxed for 10 hours. The solid turned somewhat gummy towards the latter part of the first hour. The mixture then became more free flowing as heating was continued. Let stand overnight. The yellow solid was filtered, washed with toluene and dried. The toluene filtrate was discarded. The dried solid was triturated with 1.5 liters of 10% sodium bicarbonate, filtered and the cake washed with water. The filtrate on acidification yielded 11.5 g of the starting acid. The damp product was dissolved in 4,5 liters of 95% ethanol and the solution treated with charcoal and filtered. On cooling filtrate yielded 69.5 g (55.5%) of the title compound, MP 271.5° to 274°C. 

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. 

The preparation of similar precursors suitable for the deposition of metal nitrides is analogous to the preparations of phosphorus and arsenic compounds. The initial reaction of metal trialkyls MR3 (M = A1, Ga, In) with amines (NHR 2) results in the formation of oligomeric amido compounds [R2MNR 2] (n = 2 or 3) which eliminate alkanes on thermolysis. The incorporation of a proton as a substituent on the pnictide bridging ligand has been examined, and many compounds of the type [R2MNHR ]2 have been synthesized. The presence of this proton may facilitate /3-elimination, allowing lower deposition temperatures to be used. 

Although phosphorus trisulfide (P4S6—but see below) and phosphorus pentasulfide (P4S10) have been widely used in the preparation of heterocyclic compounds there is no recent review. Weintraub has given an account of solvent- and temperature-dependent reactions of the pentasulfide, the compound employed in almost all recently reported work.118... 

In situ reaction of the resultant phosphine, converted to its conjugate base, with several types of electrophiles has been investigated for organophosphorus syntheses. While early reports of the use of white phosphorus in basic solution with haloalkanes did not in themselves provide procedures for the efficient preparation of organophosphorus compounds, they pointed the way for the development of more useful techniques. 

The method depended upon the availability of phosphorus oxydichlorofluoride, a compound described by Booth and Dutton,2 who devised an elaborate apparatus for the preparation of the compound in a pure condition for physicochemical measurements. We modified their process to suit the particular needs of this work. The generator which we developed for this step-... 

It should be emphasized that the phosphorus oxydichlorofluoride method for preparing esters of phosphorofluoridic acid cannot compare in speed with the hydrogen phosphite method already described (p. 46). Furthermore, it is not very suitable for very large-scale work. On the other hand, once the apparatus is set up and a supply of POCl2F is obtained, one has a simple, clear-cut, method for producing a large variety of phosphorus compounds, not only esters but amino compounds (p. 87) and mixed compounds (p. 90). In other words, the method is extremely valuable for exploratory purposes and where an unequivocal synthesis is required. 

Reactions with Simple Alkenes and Aromatic Compounds.—A wide range of conditions continues to be used to form phosphorus-carbon bonds between halogeno-phosphines and alkenes or benzene derivatives. A selection of such reactions (Scheme 2) is outlined for the preparation of the compounds (17)—(23).22-26... 

An unsuccessful attempt to repeat this reaction was made by Bird however, he was able to show that dibenzothiophene 5-oxide did, in fact, react with either thionyl chloride or phosphorus oxychloride to yield 2-chlorodibenzothiophene in good yield. Since all methods of nitration of dibenzothiophene yield a mixture of 2-nitrodibenzothio-phene and dibenzothiophene 5-oxide, which have identical melting points, it was concluded that the earlier workers had in fact been working with the sulfoxide and not the nitro compound. The reaction was rationalized as being a deoxygenative halogenation of a heterocyclic 5-oxide akin to the Meisenheimer reaction of A-oxides, which already had precedents in the sulfoxide field. Unfortunately the 2-chlorodibenzothiophene prepared by this route is contaminated with 2,8-dichlorodibenzothiophene which cannot be removed by crystallization. The best method of preparation of this compound is therefore via a Sandmeyer reaction on 2-aminodibenzothiophene. ... 

To investigate such reactions further, various substituted, phosphorus-rich silylphosphanes are needed as starting compounds. The following investigations aim at the preparation of phosphorus functional tri- and tetraphosphanes, in which particular phosphorus atoms with reactive substituents (H, Li, halogen, SiMe3) are built in, while other phosphorus atoms with equally defined positions remain blocked by alkyl groups. 

The reaction between dry phosphine and hydrogen iodide, first described in 1817 by J. J.Houtonde la Billardiere produces phosphonium iodide. The simplest laboratory preparation of this compound is by the hydrolysis of an intimate mixture of diphosphorus tetraiodide and white phosphorus According to X-ray diffraction investigations, phosphonium iodide crystallises in a caesium chloride type lattice 3m,32s). 326) hydrogen atoms... 

Diselenophosphate complexes are prepared from the interaction of metal salts and complexes with appropriate diselenophosphoric acid or its salt. The acids are obtained from the reaction of phosphorus(V) selenide with alcohols 229). The preparation of phosphorus(V) selenide and its reactions with alcohols 229) and amines 22°) have been described and a variety of complexes reported (Table 4). The biological activity of these compounds does not seem to have described but the exercise of extreme caution when handling these materials is recommended. Zingaro and his coworkers 229-232) thoroughly characterized the thermal and spectroscopic properties of a number of compounds. 

Of all the reactions studied, only the synthesis of nitrogen oxides and acetylene in arcs or plasma torches and that of ozone in glow and corona discharges are of major importance. In addition, a few small-scale preparations of inorganic compounds have been developed, e.g. synthesis of hydrazine and of hydrides and halides of silicon, germanium, tin, lead, phosphorus or arsenic 3> ... 

R ac.tL jity umpoiung and 6ynthztic e.quivaJte.ntA are very fruitful concepts in modern organic synthesis, in particular for the multistep preparation of natural compounds. In this area, organo-phosphorus compounds can be useful tools, particularly for reversible umpolung by heteroatom exchange (.1.-4). 

Ethyl dichlorophosphite and methyl dichlorophosphite have been prepared by the reaction of 1 mol of the appropriate alcohol with 1 mol of phosphorus(III) chloride.1 The ethyl compound has also been prepared from triethyl phosphite and phosphorus(III) chloride.2 The method outlined below is essentially the former however, several improvements have been incorporated. Among the difficulties encountered in the preparation of these compounds are the following Side reactions occur between the generated hydrogen chloride and the ester, giving an alkyl chloride and phosphorous acid disproportionation may occur in the case of the ethyl ester, the necessary vacuum distillation causes losses of the relatively low boiling product. 

There are several allotropic forms of elemental phosphorus, the most common being the white, red, and black forms. Red phosphorus, which itself includes several forms, is obtained by heating the white form at 400 °C for several hours. An amorphous red form may also be prepared by subjecting white phosphorus to ultraviolet radiation. In the thermal transformation, several substances function as catalysts (e.g., iodine, sodium, and sulfur). Black phosphorus appears to consist of four different forms. These are obtained by the application of heat and pressure to the white form. The major uses of elemental phosphorus involve the production of phosphoric acid and other chemicals. Red phosphorus is used in making matches, and white phosphorus has had extensive use in making incendiary devices. Several of the important classes of phosphorus compounds will be discussed in later sections. 

On account of the instability of the phosphines and phosphonium salts, the hydrogen valency of phosphorus is more clearly displayed in their alkyl substitution products which also, as is usual, possess a more pronounced basigenic character than the hydrogen compounds themselves. The methods of preparation of these compounds, and their properties, closely resemble those of the alkylamines. 

Phosphorus Pentasulphide or Diphosphorus Pentasulphide or Phosphorus Tetritadecasulphide, P2S6 or P4S10.—The methods which have been already described in connection with the other sulphides have been successfully used in the preparation of this compound from the theoretical proportions of the elements —... 

The phosphates of lime which occur in nature or are produced during the course of manufacture of phosphorus compounds are salts of orthophosphoric acid. The hydrogen is replaced by calcium in stages giving successively mono-, di- and tri-calcium phosphate. Of these the mono-calcium salt alone is freely soluble. The solids deposited on evaporation, or obtained by double decomposition, are generally mixtures of the di-, tri- or more basic compounds, but pure crystalline forms have been prepared, especially of the more acid phosphates. The more basic phosphates are very sparingly soluble, and the solubilities are not definite. The solids are not in equilibrium with solutions of their own composition, but are in process of transformation which is so slow that equilibrium is not attained in most operations. 

Cyclophosph(V)azanes with five-coordinate phosphorus are mostly dimeric, four-membered ring derivatives, [X3PNR]2 (6). Several reviews cover the subject. A simple preparation of these compounds involves the reaction of PCI5 with primary amines (or their hydrochlorides), the so-called Kirsanov reaction. Weakly basic amines form monomeric Cl3P=NR, but with more basic amines (e.g. with R = alkyl), the products are the cyclic dimers. Various anilines give either a monomer or a cychc dimer, depending upon their basicity. ... 

The method has been extended to the preparation of difunctional compounds. Dihalides Including the mixed variety are formed in 90 to 98% yields. Primary unsaturated bromides of the type RCH=CHCH,Br have been formed from the corresponding alcohols by the action of phosphorus tribromide and pyridine at a low temperature without any apparent rearrangement. However, the corresponding secondary-carbinol system, RCHOHCH=CH is very susceptible to allylic isomerization. The formation of a, -acetylenic bromides from acetylenic alcohols and phosphorus tribromide is common (40-70%). An acetylenic-allenic isomerization has been observed, viz.,... 

Alkyl halides, as well as sulfonates, besides being useful for the preparation of derivatives as shown above, are widely utilized for the preparation of phosphorus derivatives such as R-PPhi Hal , precursors for the generation of Wittig reagents. Alkyl halides are also extremely important as intermediates in the preparation of the most valuable derivatives of oxidation level 0, the organometallic compounds. The required reduction step is usually carried out via direct reaction of the alkyl halides with an active metal such as lithium or magnesium. 

Treatment of 7-methylxanthine with phosphoryl chloride and phosphorus pentachloride affords 2,6-dichloro-7-methylpurine (4). The preparation of this compound had previously been reported by Fischer by treatment of theobromine (3,7-dimethylxanthine) with phosphoryl chloride in a sealed tube at 140 °C. 

The effect of phosphorus on PD depends on the catalyst preparation method. The PD of catalysts prepared by impregnation decreases with phosphorus loading, whereas that of catalysis derived from the hydrogel or sol-gel methods tends to increase in some cases. Introduction of phosphorus compounds in the sol-gel procedure may affect the hydrolysis and condensa-... 

Reduction of the phosphorus-carbon bond is generally achieved with the aim of preparing new phosphorus compounds, and not with the object of preparing reduced carbon compounds. It is a striking difference from mercury-carbon bond cleavage, which is usually carried out in order to prepare carbon compounds. 

---