472 472 485 485 592 587 Table 1. Properties of compounds (3al-(3d), ( 4 a ) . and ( 4 b ) . 4.37 4.37 4.34 4.34 4.27 4.11 Received, March 23rd, 1964 [ Z 703/535 IE]A solution 0.02 mole of N-ethyl-2-chlorobenzothiazolium fluoroborate ( I ) , RI = CzHs, R 2 = H, and 0.01 mole of tris-(hydroxymethy1)phosphine (2) in 10 ml of N,N-dimethylformamide (DMF) was treated at 0 "C under nitrogen with 0.03 mole of diisopropylethylamine dissolved in 10 ml of DMFand yielded orange-red crystals of ( 3 6 ) , with elimination of formaldehyde.We obtained analogous compounds from variously substituted 2-chlorobenzothiazolium salts and 2-chloroquinolinium salts; it appears therefore that phosphacyanines (3) R2 R2 or ( 4 ) (i.e. analogues of the azacyanines) have been formed (yields: 40-50 7:). Some of their properties are listed inTable 1 . Compound H H OCH3 OCH, H CH3 225-230 214-220 208-220 215-123 126 (decomp.) 178-185Oxidation of (3a) -(Sd), (4u), and (46) by alkaline hydrogen peroxide affords 2-benzothiazolones or 2-quinolones, together with phosphoric acid, in quantitative yields.The NMR-spectra are compatible with the cyanine structure; the chemical shift of the phosphorus resonance (-26.05 pprn), however, is unexpectedly large and without parallel [*I.The excellent agreement of the electron spectra with those of the analogous aza-and rnethinecyanines supports the constitution proposed.The observation that 4-cyano-2,6-diphenylphenol ( I ) can be dehydrogenated to a stable, green phenoxyl radical [ I ] prompted us to prepare further arylcyanophenols. 2-Cyano-4,6-diphenylphenol (2) was obtained from 2,4-diphenylanisole by bromination, conversion into the corresponding organolithium compound, carboxylation, preparation of the amide, dehydration, and demethylation with pyridine/HCl [2]. Compound (2) can be dehydrogenated to a red, stable phenoxyl radical. 2,6-Dicyano-4-phenylphenol (3) was prepared from 4hydroxydiphenyl by condensation with formaldehyde to give 2,6-bishydroxymethyl-4-phenylphenol, methylation, oxidation to the dicarboxylic acid, conversion into the diarnide, dehydration, and demethylation. Phenol (3) is oxidized with lead tetraacetate in glacial acetic acid to give a blue radical which has not yet been closely investigated. Finally, we have prepared 2,4,64ricyanophenol (4) by conversion of methoxytrimesic acid into the triamide, dehydration, and demethylation. Like picric acid, (4) is a strong acid (pKc = 1.0 at 20°C and ionic strength p -0.02); it has not yet been oxidized. b H OH C: d35 C N OH 6 H The half-wave potentials were measured polarographically i n acetonitrile/water (9: I ) containing 0.01 M N(CH3)40H and N(CH3)dCI with a rotating graphite electrode and a silver! 384
