By means of P-H compounds

9-Anthrylphosphonic add 167 Anthracene (53.6 g, 0.3 mole), diethyl phosphite (170 ml, 1.33 moles), and di-/er/-butyl peroxide (30.1 ml, 0.168 mole) are heated for 4 h at 150°, whereafter much (120 ml) of the diethyl phosphite is recovered by distillation in a vacuum. The residue is treated with water (200 ml), collected, washed with water, and, for hydrolysis, heated under reflux for 72 h with a mixture of ethanol (500 ml) and concentrated hydrochloric acid (150 ml). The resulting solution is evaporated and the solid residue is heated with 5% aqueous potassium hydroxide (500 ml). Filtration and acidification then precipitate a yellow crude product (38.6 g), m.p. 279-282°, which is washed with water. For purification this product (6.5 g) is stirred with charcoal in a solution of sodium acetate (10 g) in water (100 ml) for 0.5 h at 70°. Filtration and acidification precipitate the white acid which, after drying at 120° in a vacuum, has m.p. 282-283° (dec.) (6.2 g). 

A different method was worked out for radic al substitution by cyclohexane.169 Irradiation of this hydrocarbon together with a dialkyl phosphite, phosphonous 

The chloride ABP(0)C1 formed in the absence of cyclohexane is an unimportant by-product. Use of chlorine can be avoided if it is replaced by the chloride ABP(0)C1, although then short-wavelength light (deuterium lamp, X 200 m[x) is necessary. 

Phosphorus(v) oxide reacts at 275-325° with aromatic hydrocarbons such as benzene, toluene, and naphthalene, and also with chlorobenzene, giving phosphonic anhydrides which are preferably worked up by hydrolysis to the phosphonic acids.170 Phosphorus(v) sulfides react at appreciably lower temperatures, yielding dithiophosphonic anhydrides (9) the 

Cyclohexene reacts in the same way as aromatic compounds with phosphorus ) sulfide.108 

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