Diphenyl acetal

Place 125 ml. of glacial acetic acid, 7 -5 g. of purifled red phosphorus (Section II,50,d) and 2 5 g. of iodine in a 500 ml, round-bottomed flask fitted with a reflux condenser. Allow the mixture to stand for 15-20 minutes with occasional shaking until aU the iodine has reacted, then add 2 5 ml. of water and 50 g, of benzilic acid (Section IV,127). Boil the mixture under reflux for 3 hours, and filter the hot mixture at the pump through a sintered glass funnel to remove the excess of red phosphorus. Pour the hot filtrate into a cold, weU-stirred solution of 12 g. of sodium bisulphite in 500 ml, of water the latter should be acid to litmus, pro duced, if necessary, by passing sulphur dioxide through the solution. This procedure removes the excess of iodine and precipitates the diphenyl-acetic acid as a fine white or pale yellow powder. Filter the solid with suction and dry in the air upon filter paper. The yield is 45 g., m.p. 

S,S -Dipropyl Acetals and Ketals RR C(SC3H7)2 S,S -Dibutyl Acetals and Ketals RR C(SC4H9)2 S,S -Dipentyl Acetals and Ketals RR C(SC5H i, )2 S,S -Diphenyl Acetals and Ketals RR C(SC6H )2 S,S -Dibenzyl Acetals and Ketals RR C(SCH2C6H5)2... 

Diketones 1 can be converted into the salt of an a-hydroxy carboxylic acid upon treatment with alkali hydroxide after acidic workup the free a-hydroxy carboxylic acid 2 is obtained. A well-known example is the rearrangement of benzil (R, R = phenyl) into benzilic acid (2-hydroxy-2,2-diphenyl acetic acid). The substituents should not bear hydrogens a to the carbonyl group, in order to avoid competitive reactions, e.g. the aldol reaction. 

PROPENOIC ACID, 3-NITRO-, ETHYL ESTER, (E)- [5941-50-4], 56,65 2-PROPEN-l-OL, 55,1 2-BROMO-3,3-DIPHENYL-, ACETATE [14310-15-71,56, 32... 

Diphenylacetyl chloride has been obtained from diphenyl-acetic acid with phosphorus pentachloride, phosphorus oxychloride and phosphorus pentachloride, and thionyl chloride. It has also been prepared by treatment of diphenylketene with hydrogen chloride. The methods of preparation of diphenylketene have been reviewed in an earlier procedure given in this series. To those cited in the earlier procedure should be added the debromination of a-bromodiphenylacetyl bromide with triphenylphosphine. The procedure above is a modification of that described by Staudinger. ... 

Butyl lithium, 2.5 M solution, in hexanes was purchased from Aldrich Chemical Company, Inc. Butyllithium was titrated with diphenyl acetic acid before each use. 

Butyllithium in hexane was purchased from MetalIgeselIschaft AG, Frankfurt, Germany and standardized by titration with diphenyl acetic acid. ... 

Synthesis (Kleemann et al. 1999, Janssen (Janssen), 1973 Janssen et al. (Janssen), 1973, Stokbroekx et al., 1973, Niemegeers et al., 1974) ) Treatment of 2-oxo-3,3-diphenyl-tetrahydrofuran, synthesized by treatment of diphenyl-acetic acid ethyl ester with ethylene oxide, with HBr(gas) yields bromo derivative i, which is then converted into butyryl chloride derivative ii by means of thionyl chloride in refluxing chloroform. Reaction of derivative ii with dimethylamine in toluene affords dimethyl (tetrahydro-3,3-diphenyl-2-furylidene)ammonium bromide, which is then condensed with 4-(4-chlorophenyl)-4-piperidinol by means of Na2C03 and Kl in refluxing 4-methyl-2-pentanone to provide loperamide. 

Before use, the commercial 1.6 M solution of butylllthium in hexane was titrated acldimetrically using diphenyl acetic acid as an indicator. ... 

S,S -Diphenyl acetals and ketals, to protect carbonyl groups, 198... 

The enantioselective reaction mechanism can be explained by considering the photochemical aspects and also the molecular arrangements (Scheme 36 and Fig. 7). Hydroacridine radical species 155 and 156, which satisfy both such conditions, should be preferably produced with their higher stability. Next, decarboxylation of 154 gives the diphenylmethyl radical 150. In the chiral crystal lattice of M-150 DPA, the molecular pairs of acridine and diphenyl acetic acid stack with... 

HYDROXYL GROUPS t-Butylchlorodi-methylsilane. f-Butyldimethylsilyl perchlorate. f-Butyl chloromethyl ether. Chloromethyl methyl sulfide. 9-Chloro-9-phenylxanthene. 2-Chlorotetrahydro-furane. d-Methoxyethoxymethyl chloride. 2-Tetrahydrothicnyl diphenyl-acetate. Tris(p-bromophenyl)ammonium-yl hexachloroantimonate. 

Thallium diphenyl acetate is obtained by treating the oxide with boiling glacial acetic acid, the evaporated solution depositing fine, transparent needles, M.pt. 262° C. The salt is completely soluble in hot pyridine, chloroform, toluene, ethyl acetate, or alcohol, moderately soluble in carbon tetrachloride or water, slightly soluble in ether or acetone, and insoluble in light petroleum. 

Lead diphenyl dithiocyanate.—This salt is readily obtained by mixing together aqueous solutions of lead diphenyl acetate and ammonium thiocyanate. It is a white powder, insoluble in water and the usual organic solvents, and is decomposed by silver nitrate, silver thiocyanate being deposited. The salt decomposes at its melting-point. 

Intramolecular photoinduced electron transfer in (58) leads to decarboxylation to give hydroxylactams in good yield (Griesbeck et al.), and irradiation of either the dextro or /eavo-rotatory crystals from the self-assembly of acridine and diphenyl acetic acid molecules, is reported to induce a decarboxylating condensation to give (+) or (—)-(59) with ees in the 35% region (Koshima et al,). The formation of ketones from the photolysis of nitrites is a low-yield process in... 

Standard conditions for these reactions were chosen on the basis of preliminary test reactions from which several generalizations were derived (a) reactions occur more rapidly in MeOH than EtOH and with triethyl phosphite than with trimethyl phosphite (b) where the solvent alcohol is not identical with the alcohol from which the P(III) ester is derived, partial ester exchange results in a mixed P(V) ester and (c) reactions in phenol are cleaner and result in higher yields with only minor or no contamination by products from ester exchange. It has been demonstrated that when phenol is used as the proton source, crotonaldehyde undergoes hydrophosphonylation, even at 0°C, to selectively furnish the phosphonate as its diphenyl acetal. The yield of phosphonylated crotonaldehyde diphenyl acetal in phenol at lOO C was 82% against 59% of diethyl acetal in refluxing EtOH for the same time. ... 

In a different series, Abood and Biel (I) found that the tertiary amine ZV-methyl-3-piperidyl diphenyl acetate was an anticholinergic agent which was essentially devoid of psychopharmacologic activity. Removal of the N-methyl group produced a compound with potent CNS stimulant and muscle-relaxant properties ... 

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