Phloroacetophenone

The bulky orange-yellow precipitate of the ketimine hydrochloride is separated by decanting the ether and washed twice with 20-cc. portions of dry ether. The solid is transferred to a 2-1. round-bottomed flask with r 1. of hot water. The flask is provided with a reflux condenser, and the yellow solution is boiled vigorously over a wire gauze for two hours. A small quantity (3-4 g.) of decolorizing carbon (Norite) is added, the 

After standing overnight the colorless or pale yellow needles of phloroacetophenone are filtered with suction and dried in an oven at 120° (Note 3). The yield is 20-23.5 S- (74—87 per cent of the theoretical amount) of a product which melts at 217-2190 (corr.). This product is quite pure and may be used directly for many purposes. It may be recrystallized from thirty-five times its weight of hot water, with a loss of about 5 per cent. The recrystallized material melts at 218-219° (corr.). 

A wide-mouthed entry tube for hydrogen chloride is necessary to avoid clogging due to separation of the solid ketimine hydrochloride. 

All the reagents must be dried carefully. Ordinary phloroglucinol contains two molecules of water of hydration, which is removed by drying overnight at 120°. The acetonitrile and ether used were freshly distilled from phosphorus pentoxide. 

Phloroacetophenone crystallizes from aqueous solutions with one molecule of water of hydration.1 The oven-dried crystals take up water readily on exposure to the air. Phloroacetophenone gives a wine-red color with ferric chloride in contrast to the violet color given by phloroglucinol.2 

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Phenyl iso-thiocyanate, 642,643 Phenylthioureas, 422, 655 Phenylurea, 644, 645 Phenylurethanos, 264 Phloroacetophenone, 727, 736 Phosgene, 185 Phosphoric acid, 189, 284 Phosphorus, detection of, 1043 Phosphorus, red, purification of, 193 Phosphorus oxychloride, 367 Phosphorus pentabromide, 489, 492 Phosphorus pentachloride, 799, 822, 974 Phosphorus pentoxide, handling of, 407 Phosphorus tribromide, 189, 492 Phosphorus trichloride, 367 Phosphorus trisulphide," 836 Phthalamide, 983 Phthalein test, 681 ... 

Resacetophenone and phloroacetophenone can be prepared from resorcinol and phloroglucinol, respectively, and acetonitrile in good yield (0. S., XV., 70). 

Reverse-phase chromatography has been widely used for the determination of NHDC. Two main types of mobile phase have been used, methanol/water and acetonitrile/water. Schwarzenbach (95) separated NHDC from impurities such as phloroacetophenone-4 -/3-neohesperidoside,... 

Phenolic ketones may be prepared by the Hoesch acylation reaction, which may be regarded as an extension of the Gattermann aldehyde synthesis (Section 6.10.1, p. 990). The procedure involves reaction of a nitrile with a phenol (or phenolic ether) in the presence of zinc chloride and hydrogen chloride best results are usually obtained with polyhydric phenols or their ethers, as for example in the preparation of phloroacetophenone (Expt 6.125). The formation of phenolic ketones by means of the Fries rearrangement of phenolic esters with aluminium chloride is discussed on p. 976. 

The Hoesch reaction is the most satisfactory method for preparing phloroacetophenone.3 The procedure described above is that of Robinson and Venkataraman.4 Phloroacetophenone has been obtained also by the action of acetyl chloride on phloroglucinol in the presence of aluminum chloride.2... 

Ether cleavage (I, 30 3, 7 8). Another example when phloroacetophenone trimethyl ether (I) is heated with aluminum chloride at 110°, it is converted into the dimethyl ether (2). Likewise, the 5-methoxyl group in a polymethoxyflavonc under-... 

The first method began with phloroacetophenone-4-methyl ether (50), which was prepared by an established route137), and by a newer method wherein phloro-acetophenone (51) was acylated with two equivalents of acetic anhydride to afford a mixture of the 2,4 and the 2,6-diacetoxyphloroacetophenones. The separated 2,6-isomer was methylated and subsequently hydrolyzed to the methyl ether (50). Monobenzylation of (50) afforded benzyl ether (52), which underwent facile Wittig reaction with carbethoxymethylenetriphenylphosphorane to give the 4-methyl-coumarin (49). 

Phenylurazole, 381 Phloroacetophenone dimethyl ether, 13 Phloroacetophenone trimethyl ether, 13 Phosgene, 26,94,157 Phosgene Immonium Chloride, 135 Phosphonitrilic chloride, 386-387 Phosphoric acid, 234, 235, 241, 302, 387 Phosphorus pentachloride, 388-389,401, 455,505... 

Hoesch reaction. Phloroacetophenone is prepared as follows. A mixture of phloroglucinol, acetonitrile, finely powdered zinc chloride, and anhydrous ether is... 

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