Frank, Arlen W. published the artcileSynthesis of diarylphosphine oxides by the Friedel-Crafts method, Category: catalysis-chemistry, the publication is Journal of Organic Chemistry (1959), 966-8, database is CAplus.
The reaction of mesitylene (I), durene (II), and Me5C6H (III) with PCl3 and AlCl3 under conditions normally employed for the synthesis of primary RPCl2 (IV) gave instead (after hydrolysis) good yields of R2P(O)H (V), with small amounts of R2P(O)OH (VI) as byproducts. The aromatic hydrocarbon [I, II, III or PhEt (VII)] (0.3 mole) refluxed 4 hrs. with stirring and exclusion of moisture with 1.2 moles PCl3 and 0.4 mole AlCl3, the heat source removed and 0.4 mole POCl8 added at a rate sufficient to maintain reflux, the mixture heated 30 min. and the cooled mixture diluted with 300 ml. petr. ether, the liquid decanted through a sintered glass filter and the gummy complex washed twice with 100 ml. petr. ether, the petr. ether and low boiling liquid evaporated, and the residue distilled in vacuo through a 20 cm. Vigreux column gave only 52% IV (R = EtC6H4) (VIII), b0.8 70-82¡ã. No IV were obtained under these conditions from I, II, or III. VIII (0.1 mole) hydrolyzed with alc.-H2O according to Kosolapoff and Powell (CA 45, 2891h) gave an oily mixture, separated by conversion to the Na salts and taking the product up in Me2CO, separating the insoluble Na salt, and reconverting to give 35% RPH(O)OH (IX) (R = p-EtC6H4), m. 67-8¡ã (C6H6). The remainder of the oily mixture consisted of 52% oily IX (R = o- and m-EtC6H4), yielding Na salts soluble in Me2CO. The residue containing the AlCl3-POCl3 complex added in small portions to 1 l. H2O with exothermic reaction and evolution of HCl and petr. ether vapors, the liquid decanted and extracted 3 times with 100 ml. C6H6, the gummy residue triturated with C6H6 and the combined C6H6 solutions washed with H2O, the HCl-free solution extracted with dilute NaOH and washed with H2O, filtered, and evaporated gave V (R = 2,4,6-Me3C6H2) (X), V (R = 2,3,5,6-Me4C6H) (XI), m. 150¡ã (decomposition) (C6H6), and V (R = Me5C6) (XII), m. 240¡ã (decomposition) (C6H6), in 59, 43, and 27% yields, resp. VII gave no phosphine oxide. Acidification of the NaOH extract with dilute HCl and extraction with C6H6 gave VI (R = EtC6H4), forming a pale blue crystalline Cu salt, VI (R = 2,4,6-Me3C6H2), m. 167-8¡ã (C6H6), VI (R = 2,3,5,6-Me4C6H) (XIII), m. 234-5¡ã (C6H6), VI (R = Me5C), frothing on drying in vacuo, in 36, 5, 4, and 4% yields, resp. V were oxidized to establish their relationship with VI. Following failures with alk. H2O2 and alk. KMnO4, 1 mmole XI was slurried with 0.40 g. NaOH and 2 mmoles K3Fe(CN)6 in 50 ml. H2O and the mixture stirred 2 hrs. with heating to 80-90¡ã, the cooled solution filtered and acidified with HCl, extracted 3 times with C6H6 and the C6H6 solution extracted twice with H2O, the aqueous extract filtered, and evaporated to dryness to give quant. the corresponding VI. X required 30 min. for complete oxidation but XII was only 14% oxidized in 14 hrs., the stability of V toward oxidizing agents increasing markedly with increasing ring substitution. The chem. evidence and the method of isolation supported the tetracovalent form for V and the infrared spectra clearly showed the presence of bands assigned to Pú´H and to P ¡ú O and the absence of the Pú´OH band present in XIII (compound, ¦Í of Pú´H, P ¡ú O, and Pú´OH in cm.-1 given): X, 2335, 1175-1189, -; XI, 2380, 1160-1190, -; XII, 2340, 1170, -; XIII, -, 1160-1175, 2500-2780.
Journal of Organic Chemistry published new progress about 23897-16-7. 23897-16-7 belongs to catalysis-chemistry, auxiliary class Aryl phosphine ligand,Mono-phosphine Ligands, name is Dimesitylphosphine oxide, and the molecular formula is C18H23OP, Category: catalysis-chemistry.
Referemce:
https://courses.lumenlearning.com/boundless-chemistry/chapter/catalysis/,
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