1-phenyl-l-butanone

Z)-4-chloro-3-methyl-l-phenyl-I-butanone oxime yield 41%... 

Problem 17.5 (a) Show the tautomers of each of the following compounds, which are written as the more stable form (1) CH,CHO, (2) C.HjCOCHj, (3) CHjNO, (4) Me.C NOH, and (5) CH,CH=NCHj. (b) Which two enols are in equilibrium with (i) 2-butanone, and (ii) l-phenyl-2-butanone Which is more stable ... 

The product from the reaction of l-phenyl-2-butanone with LDA and methyl iodide shows a quartet (1 H), a quartet (2 H), a doublet (3 H), and a triplet (3 H) in the alkyl region of its H-NMR spectrum. Show the structure of this product and explain the regiochemistry of the reaction. 

In the same domain of heterocyclic synthesis, much effort has been devoted to understanding the selectivities in the synthesis of indoles starting from phenylhydrazine and ketones, i.e. the Fischer indole synthesis. With phenyl-hydrazine, l-phenyl-2-butanone and zeolite H-Beta, the slimmer product 2-phenyl-3-methylindole dominates over the more bulky isomer (13) ... 

H. van Bekkum et al. (72) studied a number of catalysts in the Fischer synthesis starting from l-phenyl-2-butanone 40 (with R, = Ph, R2 = CH3) and phenylhydrazine. The isomeric products are the bulky 2-ethyl-3-phenylindole 45 (with R, = Ph, R2 = CH3) and the linear 2-benzyl-3-methylindole 46 (with R, = Ph, R2 = CH3). Catalysis of the inolization of 40 by soluble as well as solid (e.g. Amberlyst 15) catalysts typically yielded a mixture of the two isomers in a bulky/linear ratio of about 75/25. Zeolite BEA reverses this bulky/linear ratio giving 75% of the linear isomer 46, a result interpreted in terms of restricted transition-state selectivity. Although in zeolite BEA the intraporous formation of 45 is largely suppressed, it is in fact probably not completely inhibited. 

The selective Fischer synthesis of 2-benzyl-3-methylindole from l-phenyl-2-butanone and phenylhydrazine and catalyzed by zeolite BEA can be considered as an interesting example of restricted transition state selectivity. 

Warfarin (= l-(4 -I Ivdroxv- V-cout narinvh-1 -phenyl-3-butanone] (coumarin)... 

Ketones-. 3-Hexanone (50), 2-hexanone (49), 3-undecanone (7S), l-phenyl-2-butanone (72), 5-methyl-3-heptanone (59) ... 

Compounds include alcohols, acids, esters, carbonyls, ketones, and other hydrocarbons. However, a particular ketone l-(4-hydroxy phenyl)-3-butanone has an odor very much like raspberry [7,30]. This particiilar ketone, i.e., raspberry ketone, is sold under trade names Frambinon (Dragoco) and Oxyphe-nylon (IFF). In Hawai, the acetate of raspberry ketone is used under the trade name of Cue-Lure CAS No. [3572-06-3] to attract the harmhil melon-fly, Dacus Curcurbitae. 

In attempts to disentangle the different factors contributing to regioselectivity, the systematic studies of Rigutto [19] were extended by Kunkeler et al. [23]. In addition to l-phenyl-2-butanone these workers also employed 1-phenyl-2-propa-none (Rj = Ph, R2 = H in Scheme 1) and 3-heptanone (Rj = Et, R2 = n-Bu in Scheme 1) as substrates, the latter as a non-methyl ketone with no phenyl group, thus obviating the possibility of complications as a result of conjugation in the transition state [2]. 

Experiments were first conducted with acetic and polyphosphoric acids, and with several concentrations of H2SO4. As expected for a methyl ketone, with 1-phenyl-2-propanone phenylhydrazone use of PPA catalyst resulted in a large variation in isomer ratio (see Table 1). With 3-heptanone the variations resulting from use of different acids were much smaller. Of several active zeolite catalysts tested, H-beta was found to be the most selective heterogeneous catalyst for the synthesis of the linear isomer from 3-heptanone and l-phenyl-2-butanone phenylhydrazones whereas, in contrast, H-Na-Y gave about equal amounts of both isomers. 

Butylbenzene n. a. 1-Butylphenols n. a. 1-Phenyl-l-butanol, 1-phenyl-3-butanol, 1-phenyl-l-butanone, 1-phenyl-3-butanone 30... 

Thionyl diloride added below 0 to dimethylformamide, the resulting soln. mixed with l-amino-l-phenyl-2-butanone hydrochloride, and heated 1.5-2 hrs. at 60-90° on a water bath after the initial exothermic reaction has ceased 4-hydroxy-5-methyl-3-phenylisothiazole. Y 78%. F. e., also with sulfur monodiloride, s. T. Naito et al., Bull. Chem. Soc. Japan 41, 959, 965 (1968). 

Zeolites can promote the cyclisation of ketone phenylhydrazones [43]. The phenylhydrazones of acetone and cyclohexanone cyclise in good yields to methylindole and tetrahydrocarbazole, respectively, in the presence of CaX zeolite. Zeolite beta is a highly selective catalyst for the synthesis of 2-benzyl-3-methylindole from phenylhydrazine and l-phenyl-2-butanone (e.g. equation 4.5) [44]. Clays have been reported to promote the ring closure of phenylhydrazones in a similar way [45]. Montmorillonite clay catalyses the ring closure of iV-benzylidene anilines with vinyl ethers to yield tetrahydroquinolines and azetidine derivatives [46]. 

PPDC catalyzes in vivo the condensation of phenylpyruvic acid 77 and acetaldehyde 28 for the synthesis of 3-(R)-hydroxy-l-phenyl-2-butanone 78 (Scheme 28.33). This enzyme is the least studied of the decarboxylases however, its uncommon substrate scope makes this enzyme a... 

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... 

Phenyl-l,3-butanedione, b63 4-Phenyl-2-butanone, b77a Phenyl cellosolve, p72 Phenyl chloride, c47 Phenylcyclohexane, c376... 

One approach that avoids the release of potent electrophiles into the general cellular milieu is use of the quiescent affinity label.1131 These evolved from the classic (non-quiescent ) affinity labels such as L-l-chloro-3-tosylamido-4-phenyl-2-butanone (Fig. 7a)... 

Exercise 17-3 Explain why the d or l enantiomer of a chiral ketone such as 4-phenyl-3-methyl-2-butanone racemizes in the presence of dilute acid or dilute base. 

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