1- Phenyl-l-pentanone

NMR spectra of 1-phenyl-l-pentanone. (a) Normal spectrum, (b) DEPT spectrum recorded using a pulse sequence in which CH3 and CH carbons appear as positive peaks, CH2 carbons as negative peaks, and... 

A mixture of 7.3 parts l-chloro-4,4-di-(4-fluorophenyl)-butane, 5.1 parts l-phenyl-4-oxo-l,3,8-triaza-spiro(4,5)-decane, 4 parts sodium carbonate, a few crystals of potassium iodide in 200 parts 4-methyl-2-pentanone is stirred and refluxed for 60 hours. After cooling the reaction mixture is treated with water. The organic layer is separated, dried, filtered and evaporated. The solid residue is recrystallized from 80 parts 4-methyl-2-pentanone, yielding l-phenyl-4-oxo-8-[4,4-di-(4-fluorophenyl)-] butyl-1,3,8-triaza-spiro(4,5)decane, melting point 187.5° to 190°C. 

This method, an adaptation of a previously described procedure,2- 8-4 has been used with a variety of amino acids and anhydrides to give the following products 1-phenyl-1-propionamidO-2-butanone (75%) 6 acetamidoacetylacetone (60%) 6 N-methyl-acetamidoacetone 6 l-phenyl-2-acetamido-3-butanone (79%) 7 l-phenyl-2-propionamido-3-pentanone (41%) 7 l-phenyl-2-butyr-amido-3-hexanone (27%) 7 a-benzamidopropiophenone (42%) 7 a-benzamido-/3-phenylpropiophenone (44%) 7 1 -phenyl-1 -aceta-midoacetone (72-90%) 8-91-phenyl-1-benzamidoacetone (65%) 8 l-phenyl-2-benzamido-3-butanone (78%) 8 3-benzamido-2-buta-none (65-88%) 8 and 3-acetamido-5-methyl-2-hexanone (73%).10... 

To a solution of 1.77 g 2-nitro-5-phenyl-3-pentanone (8.53 mmol) in 5 mL MeOH was added 10 mL MeOH solution of 1.65 g (p-tolylsulfony l)hydrazine (8.9 mmol) the mixture was stirred for 10 h, then water was added to precipitate 2-nitro-5-phenyl-3-pentanone (p-tolylsulfonyl)hydrazone, which was purified by recrystallization from MeOH/water, in a yield of 90%, m.p. 104-105°C. 

Aq. hydrazine added dropwise with stirring below 55° to a mixture of 4-methyl-4-nitro-3-phenyl-l-(3-pyridyl)-l-pentanone and Raney-Ni, stirring continued 2 hrs. 5,5-dimethyl-4-phenyl-2- (3-pyridyl) -Zl -pyrroline 1-oxide. Y 70-75%. F. e. s. M. G. Kloetzel et al.. Am. Soc. 83, 1128 (1961). 

Melhyl-1.3-diphenyI-pentanon-(l), a-Methyl- -phenyl-T erophenon 7 1 248,... 

The mechanism of photo-oxidative degradation of polystyrene was also investigated using low molecular compounds such as benzene 3-phenyl-pentane [1356] 2-phenylbutane [1360, 1361] 1,3-diphenylpropane-l-one [719, 725] 1,3-diphenylpropane 1,3-diphenylbutane 2,4-diphenylpentane [1293] cumene cumene hydroperoxide [759] acetophenone hexanoic acid 3-heptanone y-valerolactone 2-phenyl-2-propanol [1250, 1397] benzal-dehyde benzoic acid l-3-diphenyl-propanone-3 l,3-diphenyl-buten-2,3-on-l (dypnone) l,3-diphenylpropen-2,3-on-l (chalcone) l-phenyl-butanedion-2,3 l-diphenylpropanedion-1,2 l-phenyl-butanedion-1,3 phenylacetic aldehyde l,5-diphenyl-pentanone-3 4-phenyl-butanone-2 [1250]. 

A soln. of 4-hydroxy-4-methyl-5-phenyl-2-pentanone in 48%-HBr-glacial acetic acid heated 2 hrs. on a steam bath 1,3-dimethylnaphthalene. Y 87-90%. -The above mixture of HBr and acetic acid (Bradsher s reagent) gave higher yields than other acids. F. e. s. P. Ganonne, P. Holm, and L. G. Leitch, Gan. J. Ghem. 45, 2151 (1967). 

In exploring various synthetic methods for the preparation of 1,2-oxaphospholene 2-oxides we investigated the reaction of diacetone alcohol (4-hydroxy-4-methyl-2-pentanone) with methyl and phenylphosphonous dichloride, which was reported (1) to proceed as shown in eq (1) to give 2,3,3,5-tetramethyl-l,2-oxaphos-phol-4-ene 2-oxide or the corresponding 2-phenyl derivative. 

The higher rate of HC1 elimination of 4-chloro-l-phenyl-1-butanone with respect to 5-chloro-2-pentanone by a factor of 9.9 confirmed the participation of the C=0 group. The 7r-electron delocalization of the benzene ring increases the basicity and nucleophilicity of the carbonylic oxygen and led to greater stabilization of the transition state through assistance to the C—Cl bond cleavage in the transition state (equation 80). 

SYNTHESIS OF (2R,3S)-2,3-DIHYDROXY- l-(2-METHOXY-PHENYL)-5-PHENYL-1 -PENTANONE BY THE FIRST GENERATION Et2Zn/LINKED-B INOL = 2/1 COMPLEX... 

Pentyl-(3)-l-[3-phenyl-pentyl-(3)]-hydrazin (R1 = R2 = C2H5)11 51,5 g (0,209 Mol) frisch destilliertes Pentanon-(3)-[3-phenyl-pentyl-(3)]-hydrazon werden in Athanol iiber 2 g Platin(TV)-oxid bei 2073-4 bar hydriert. Nach Beendigung der Wasserstoff-Aufnahme (—24 Stdn.) wird filtriert, i. Vak. unter Stickstoff einge-dampft und unter Stickstoff iiber cine Spiralsaulc dcstillicrt Ausbcute 44,5 g (81% d.Th.) Kp o 110° no — 1,5012. 

Dimethylpropanoic acid is the best additive11. Thus, hydrogenation of 1-phenylethanone with the Raney nickel/tartaric acid/sodium bromide/2,2-dimethylpropanoic acid system gave (5>)-l-phenylethanol in 63%ee. 2-Butanone was reduced to (,V)-2-butanol in 49% ee, while the optical inductions in the hydrogenation of 2-alkanones, ranging from 2-pentanone to 2-hene-icosanone, were between 58 and 66% ee. 4-Phenyl-2-butanone was reduced to (S)-4-phenyl-2-butanol in 58% ee, while the best result was achieved with 3,3-dimethyl-2-butanone yielding (S)-3,3-dimethyl-2-butanol in 74% cc11. 

R = C6Hj 5-(hydroxyethy )-3-phenyl-4,5-dihydro-l,2-oxuzole 2 R = 2-furyl 1 -(2-fury l)-3,4-dihydroxy-1 -pentanone... 

ANNELATION f-Butyl-7-iodotiglate. l-Chloro-3-pentanone. 1-Fluorovinyl methyl ketone. 1-Lithiocyclopropyl phenyl sulfide. Methyl a-trimethylsilylvinyl ketone. 

B.iv. Nitrile Enolates. Nitrile enolates are formed by reaction of a nitrile with LDA or another suitable base. Both alkylation 30 and condensation reactions with aldehydes 3 or ketones are known. 32 in addition to alkyl halides and carbonyl derivatives, condensation can occur with another nitrile. The base-catalyzed condensation of two nitriles to give a cyano-ketone, via an intermediate cyano enolate, is known as the Thorpe reaction. 33.109e Reaction of butanenitrile with sodium ethoxide gave a nitrile enolate, which reacted with a second molecule of butanenitrile at the electrophilic cyano carbon to give 206. Hydrolysis gave an intermediate imine-nitrile (207), which is in equilibrium with the enamine form (208, sec. 9.6.A). Hydrolysis led to the final product of the Thorpe reaction, an a-cyano ketone, 209. 33 Mixed condensations are possible when LDA and kinetic conditions are used to generate the a-lithionitrile (a mixed Thorpe reaction). When pentanenitrile was treated with LDA and condensed with benzonitrile, 2-cyano-l-phenyl-1-pentanone was the isolated product after acid hydrolysis. Nitrile enolates can also be alkylated with a variety of alkyl halides. 34... 

Thus, a short-range strategy for the synthesis of 4-hydroxy-l-phenyl-pentanone-2 (I) will lead to the two carbonyl compounds methyl benzyl ketone and acetaldehyde as synthesis precursors (Figure 1). Having reached this conclusion it is absolutely necessary to consider whether those two precursors will react by the anticipated aldol condensation to the target compound (I). A closer inspection based on insight into chemical reactivity has to decide that this reaction will not proceed unequivocally to the desired product (I). Rather, a mixture of compounds will be obtained including the... 

At 140 °C, with Pco = 40 Kg/cm, a substrate/catalyst ratio of 20, for 16 h, a complete conversion was observed and the 1-pyrroline was obtained with 91 % selectivity (4-methyl-4-nirto-l-phenyl-1-pentanone as substrate). Substituted phenanthrolines and 2,2 -bipyridine were less effective as cocatalysts. Other ligands performed poorly in this reductive heterocyclisation. 

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