Acetone, acetyl 1-phenyl

The a proton of a substituted cyclopropane is also rendered acidic if the substituent is attached to the ring by C-P bonds. A few reports have appeared on a-substitution in such compounds.(Cyclopropyl)triphenylphosphonium bromide was converted to a (1-ethoxy-carbonylcyclopropyl)triphenylphosphonium salt 18 in 80% yield by sequential treatment with lithium diisopropylamide and ethyl chloroformate. Furthermore, some diethyl cyclopropyl-phosphonates were converted, in some cases in excellent yield, to diethyl (1-hydroxymethyl-cyclopropyl)phosphonates by treatment with lithium diisopropylamide followed by addition of an aldehyde." Thus, typically, diethyl 2-hexylcyclopropylphosphonate gave diethyl 2-hexyl-l-[hydroxy(phenyl)methyl] cyclopropylphosphonate (19b) in 90% yield on reaction with benzaldehyde. ° Other electrophiles such as acetone, acetyl chloride, acetic anhydride, and ethyl acetate, were not sufficiently reactive to undergo addition to the anion. 

Photolysis of acetone forms methyl radicals, isolated as dimethyl-mercury, and acetyl radicals isolated as diacetyl. Photolysis of benzo-phenone forms phenyl radicals which remove a tellurium mirror to give diphenyltellurium. 

The method described is that of Hampton, Harris, and Hauser6 and is an improvement over the benzyne method, which gives poor yields.6,7 This /J-diketone has been prepared by Claisen condensation of ethyl phenylacetate with acetone,8 but the yield is poorer and the product has been shown by gas chromatography to be impure.6 The j8-diketone has also been prepared by the hydrolysis of 4-methoxy-5-phenyl-3-penten-2-one and by hydrolysis and decarboxylation of ethyl a-acetyl-/3-oxo-y-phenylbutyrate10 but these compounds are more difficult to obtain than the starting materials used in the present synthesis. 

In polar solvents such as chloroform, dichloromethane, acetone, and acetonitrile, the fluorescence quantum yields of 97a-d decrease by varying degrees (see Table 19). Moreover, in the case of the phenyl and acetyl derivatives 97c and 97d, the rather drastic decrease of the structured fluorescence from the locally excited anthracene is associated with the appearance of a structureless, red-shifted emission which is attributable to an intramolecular exciplex. For 97d, in which the electron acceptor properties of the aromatic carbonyl moiety are enhanced by p-acetyl substitution, exciplex emission is dominant even in toluene solution (see Figure 22). 

Deprotection of the disaccharide 2 was accomplished by cleaving off the phenyl groups by hydrogenolysis over platinum and the acetyl groups by treatment of the methanolic solution with ammonia. After removal of excess ammonia, the monoammonium salt of the unprotected disaccharide 2 was isolated by precipitation with acetone. The yield was 55, [aj +21 ° 0 255 ... 

Configurational proofs for 86,90,88, and 91 were obtained by n.m.r. analysis of 92 and 93, and 94 and 95. Compounds 92 and 93 were obtained from 86 and 90, respectively, by successive treatment as follows partial hydrolysis with acid, periodate oxidation, acid hydrolysis, acetonation, and acetylation. Compounds 94 and 95 were similarly prepared from 88 and 91, respectively. The main argument in favor of the structures assigned was that, in 94 and 95, the acetoxy-methyl group is shielded by the phenyl substituent and resonates... 

The photochemistry of more complex and highly substituted alkenic partners has been studied. In 1978, Hartmann and coworkers reported the photocycloaddition of 4-oxazolin-2-one with acetone, used as a photosensitizer in the reaction of 4-oxazolin-2-one with alkenyl and alkynyl partners, to form oxe-tane (44). Recently, Scharf has described the photochemistry of 3-acetyl-2,3-dihydio-2,2-dimcthyloxa-zole (45). Irradiation of (45) in the presence of acetophenone produced the oxetane (46) with the phenyl group endo (17%), in addition to 21% of a ring-opened derivative. The stereoselectivity is in agreement with the high exo carboxyl selectivity observed in the photocycloaddition of methyl phe-nylglyoxylate with 2,2-dimethyl-1,3-dioxole to produce oxetane (47). 

Helfcrich and GriebeP devised a general method for the preparation of phenyl lactosides by treating the potassium phenoxidc with hcpta-0-acetyl-a-lactosyl bromide in acetone. 

Several 4-substituted 3-methyl-3,4-dihydroquinazolines were obtained by addition of nucleophilic bases across the 3,4 double bond of the 3-methyl-quinazolinium cation, and carbon nucleophiles (e.g., acetyl acetone) added across the 3-4 double bond of 3-phenyl-2-oxo(or thio)-(lH)-quinazolinium salts in much the same way. ... 

QH, CH(CH3)2 ch2-c6h5 K K K CN CO-NH-COOC2lI5 CH=CH-CN —< )—no2 co-ch3 Cl Cl Br Cl Cl Aceton/(H5C2)3N Ethanol/(H5C2)3N Ethanol/(H5C2)3N Aceton/(H5C2)3N Ethanol/(H5C2)3N Ruckfl. Ruckfl. Ruckfl. Ruckfl. Ruckfl. 0,5 0,52 1,5 3 2,25 4-Amino-5-cyan-2-propylthio-... 4-Amino-5-(ethoxycarbonyt-aminocarbonyl)-2-isopropylthio-... 4-Amino-2-benzylthio-5-(2-cyan-ethenyl)-... 4- Aminv-2-benzytthio-5-(4-nitro-phenyl)-... 5- Acetyl-4-amino-2-benzylthio-... 79 55 46 48 80 111,5 114-118 156 140 116 737 733. 764 725 881 758... 

Fig. 11.5 Positions of the HOMO and LUMO levels for various Ir-dyes, compared to some charge-transporting materials frequently used in OLEDs [27], Here, niBr stands for N-2,6-dibro-mophenyl-1,8-naphthali-mide, Irppy for lr(ppy)3, Btlr for bis(2-phenyl-benzothiozolato-n,C2)iri-d i u m (acetyl-acetonate), Btp(lr) for btp2lr(acac), Alq3 for Aluminium(lll)-tris(8-hydroxyquinoline), NPD for 4,4 -bis(N-(l-napthyl)-N-phenylamino)-biphenyl and CBP for 4,4 -N,N -dicarbazolebi-phenyl.

In hquid state, the percentage of enol forms in acetylacetone and benzoyl acetone is 80% and 89%, respectively. The enol form of benzoyl acetone gets further stabilization, besides the intramolecular hydrogen bonding shown above for acetyl acetone, due to conjugation of the carbon-carbon double bond with the phenyl group (Scheme 3.49). 

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