Reactions with Phosphorus Pentachloride

Phosphorus pentachloride, for conversion of pentaacetylgluconic add to add chloride, 41, 80 for oxidation of cycloheptatriene to tropylium fluoborate, 43, 101 with cyanoacetic acid, 41, 5 Phosphorus tribromide, reaction with 1.5-hexadien-3-ol, 41, 50 Phthalic anhydride, reaction with L-phenylalanine to yield N-phthalyl-L-phenylalanine, 40, 82 Phthalic monoperacid, 42, 77 N-Phthalyl-i.-alanine, 40, 84 N-Phthalyl-/3-alanine, 40, 84 N-Phthalylglycine, 40, 84 N-Phthalyl-l-/5-phenylalanine, 40, 82... 

B. From Cyano-compounds and Phosphorus(v) Halides.—Continued reports of the reactions of alkyl cyanides with phosphorus pentachloride appear. With dicyanides the formation of phosphazenes occurs via a series of intermediates whose stability varies with the nature of X ... 

Subsequent reactions with phosphorus pentachloride and with its monophenyl derivative lead to the dimer (Cl3PNMe)2 and A-sulphonylphos-phazenes ... 

Reactions of Phosphoranes.—The reactions of phosphorus pentachloride (101) with simple organic molecules continue to attract attention, notably in the Russian literature. For example, the preparative uses of alkene-addition reactions of (101) have been examined for a-methylstyrene (102), as outlined in Scheme 7.85... 

Phosphorus pentachloride, for conversion of pentaacetylgluconic add to acid chloride, 41, 80 with cyanoacetic add, 41, 5 Phosphorus tribromide, reaction with... 

Hydrolysis of Phosphorus Pentachloride. Introduce a small amount of the prepared phosphorus pentachloride into distilled water. What do you observe Write the equation of the reaction and establish the composition of the products formed when phosphorus pentachloride reacts with water. 

Chlorobenz[d]isothiazole-l, 1-dioxide ( pseudosaccharin chloride ) (6)3,24.25, lee, 25i, 26i, 262 displays the reactivity of a cyclic imidoyl chloride263 resembling very much carboxylic acid halides. In previous sections preparation of 3, 4, 5, 13, 68, 86, 89 from 6 has been mentioned. Derivatives of 6 substituted in the phenyl ring have been described.250 Interestingly, Meadow observed231 that crude 6 and material that contained phosphorus pentachloride reacted with thiols more readily than the pure compound. In the reaction of 6 with aromatic sulfonamides, aluminum chloride had been added for activation.252... 

The reaction with thionyl chloride affords a chlorosulfite, the decomposition of which may generate an alkyl chloride by the S i (substitution, nucleophilic, internal) mechanism (Scheme 2.16). This reaction, w hich may proceed by an ion pair, can lead to the retention of configuration of an asymmetric secondary alcohol in the conversion to the alkyl chloride. This is in contrast to the inversion of configuration found with the reaction with phosphorus pentachloride and with the nucleophilic displacement of a leaving group. 

Both phosphorus trichloride and phosphorus pentachloride react with water in a hydrolysis reaction, a reaction with water in which new element-oxygen bonds are formed and there is no change in oxidation state. An oxoacid and hydrogen chloride gas are formed in the reaction. 

Application of this method to heterocyclic acids permits easy preparation of acid chlorides previously requiring special procedures. Thus 5-methyl-3-isoxazole-carbonyl chloride was initially obtained only by the reaction of the sodium salt of the acid with phosphorus pentachloride" or with thionyl chloride the free acid does not react with thionyl chloride alone. An improved procedure is as follows."... 

Phosphorus pentachloride reacted with anthrone 9a/9b at room temperature to give tetrachlorophosphorane 10) which decomposed on heating with more PCI5 to form 9,10-dichloroanthracene (12) presumably via 11. The analogous reaction of PCI5 with 1-hydroxyanthrone (13) was considerably more complicated, however, and proceeded via (14) to give (15). 

Preparative uses of the reactions of phosphorus pentachloride (78) with simple phosphines have been investigated. Thus tertiary phosphines give mainly the chlorophosphonium salts (79), whilst chlorophosphines give chlorophosphoranes (80 = 1 or 2). An impressive combination of n.m.r. and C1 n.q.r. spectroscopy has revealed that the phosphoranes (80) are molecular in the solid state, and that the phosphoranes (81) and (82) are ionic in the solid state. ... 

The reactions of phosphorus pentachloride (78) with electron-rich alkenes continue to be prominent in the Russian literature, and a few selected examples are given in Schemes 7 and 8. In the reaction of (78) with 2-methylpropene, the formation of... 

A number of reactions of phosphorus pentachloride (78) with carbonyl compounds have been reported. a-Hydroxycarboxylic acids, such as malic and tartaric acids, react with (78) to give phosphorodichloridates with general part-structure (110). The heterocyclic hydrazide (111) is converted into the cyanide (112), and hence into the isomer (113), by treatment with (78) in refluxing benzene. ... 

The reaction of phosphorus pentachloride (81) with acetaldehyde under mild conditions is believed to yield a 1 2 complex, which on treatment with... 

The reactions of phosphorus pentachloride (81) with olelins continue to be studied, notably by Russian groups. These reactions generally result in formation of a complex, the nature of which is not always clear, followed by decomposition of the complex either thermally or by the action of a chemical such as sulphur dioxide. For example, the vinyl ether (94) reacts with (81) in... 

---