Ketone, l-

Dibenzyl ketone (l,3-diphenyl-2-propanone) [102-04-5] M 210.3, m 34.0 . Fractionally crystd from its melt, then crystd from pet ether. Stored in the dark. 

The 3,4-dihydrodiol of BcP was synthesized from 4-oxo-l,2,3,4-tetrahydro-BcP (15) by Method I (66). The ketone L was itself prepared from 4-oxo-l,2,3,4-tetrahydrophenanthrene via a multistep sequence entailing Reformatsky reaction with methyl bromocrotonate, dehydration of the resulting alcohol, isomerization to the aryl-butyric acid, and cyclization of its acid chloride with SnCl - Full... 

Nitrone cycloaddition reactions with alkynes have been widely used for the synthesis of imidazolidine nitroxides (736) and (737), containing chelating enam-ino ketone groups (821). Different heterocyclic systems were obtained, such as 3-(2-oxygenated alkyl)piperazin-2-ones (738) (822), also compounds containing the isoxazolo[3,2-i]indole ring system (739) (823) and a new class of ene-hydroxylamino ketones- (l )-2-( 1-hydroxy-4,4,5,5-tetraalkylimidazolidin-2-ylidene)ethanones (740) (824) (Fig. 2.46). 

Reduction of cyclic ketones.l These complexes selectively reduce cyclic ketones to the less stable alcohol. The most stereoselective reagent is that in which the R group is /-butyl this complex is comparable to lithium trisiamylborohydride in stereoselectivity. 

Rajasekar.J. and Naidu, P.R. Speedof sound of 1.3-dichlorobenzene + methyl ethyl ketone + l-alkanolsat303.15 K,/ Chem. Eng. Data, 41(l) 373-375. 1996. 

Most of the reduced thiazole derivatives were obtained from the reaction between l -Cys or its esters with aldehydes or ketones. L-Cystine reacts with formaldehyde at room temperature to give 4(f ) -thiazolidinecarboxylic acid 32 without racemization [36JBC(114)341 37JA200 78JMC1070]. 

Typical examples are listed in Table 2.1. A few oxidations are effected by RuO but in general it is too powerful an oxidant for this purpose. The system RuCyaq. NaCl-CCy Pt anode oxidised benzyl alcohol to benzaldehyde and benzoic acid and p-anisaldehyde to p-anisic acid [24], and a wide range of primary alcohols and aldehydes were converted to carboxylic acids, secondary alcohols to ketones, l, -diols to lactones and keto acids from RuOj/aq. NaCl pH 4/Na(H3PO )/Pt electrodes (Tables 2.1-2.4). The system [RuO ] "/aq. K3(S303)/Adogen /CH3Cl3 oxidised benzyhc alcohols to aldehydes [30]. The oxidation catalyst TPAP (( Pr N)[RuO ]) (cf. 1.3.4) is extremely useful as an oxidant of primary alcohols to aldehydes and secondary alcohols to ketones without... 

Keton l-Amino-3-oxo-l-alken Reagenz [%] P-Amino-keton [%] ... 

The "impact compound that provides the primary stimulus for fruit character in the raspberry is the ketone, l-(p-hydroxphenyl)-3-butanone 11). Other important flavour contributors are cw-3-hexen-l-ol, a - and p - ionones, and a - irone (72, 13). In R. arcticus the characteristic aroma is considered to be from mesifiirane (70). It has, however, been reported that steam distillates of raspberries can be assessed for aroma content using a colorimetric procedure and 80% of aroma is accounted for by geraniol, nerol, linalool, a - terpineol and die ionones (13). 

Interestingly, Lewis acid catalyzed rearrangement of 6-methyltricyclo[8.2.0.0, 6]dodecan-9-one gave the spiroannulated triquinane ketone (l/ , 5/ )-l-methylspiro[bicyclo[3.3.0]octane-2,lf-cyclopentane]-6-one as the major product (70%).85... 

Solvato complexes of platinum(II) of the type fraws-[PtY(solvent)L2]+ (Y = hydride, alkyl, or aryl solvent = alcohol or ketone L = tertiary phosphine or arsine) have been known since 1961.1 They are obtained by halogen abstraction from the corresponding halo complexes tran.s-[PtXYL2] in the presence of the desired solvent.2 The methanol complex is also rapidly and quantitatively formed when trans-[PtH(N03)(PEt3)2] is dissolved in this solvent.2... 

Hydrozirconation of alkyne 14, followed by cuprate addition, was then used to install the Cl3 20 side chain of 15. Reduction of the ketone (L-selectride) followed by hydrogen fluoride cleavage provides the F-series derivatives 16, while direct cleavage of 15 gave the E-series compounds 17. 

The final step in a synthesis of modhephene (3) involved addition of a methyl group to the hindered ketone l.J The ketone does not react, however, with... 

The amino acid chloromethyi ketone (l.Ommol) was dissolved in DMF (4-7mL mmol-1) and Nal (1.1 mmol) was added. The mixture was stirred for 15 min. The peptide ester salt (1.1 mmol) in DMF (2-5 mL mmol 1) was added, followed by NaHC03 (2.1 mmol), and the reaction left to stir for 12-18 h at rt. The soln was then diluted with EtOAc (50-70 mL) and washed with H20. The aqueous layer was extracted (x 2) with EtOAc and the combined extracts were washed with H20 and brine before drying (Na2S04). The resulting (oxomethyleneamino) peptide was of good purity silica gel chromatography, carried out to remove trace impurities, may contribute to epimerization at the chiral center a to the ketone carbonyl. 

Bromomethyl ketones.l Reaction of (dibromomethyl)lithium (1) with esters and then with BuLi (excess) generates the enolate (a) of a bromomethyl ketone. Quenching with acidic ethanol gives the bromomethyl ketone (2) in 70-85% yield. Quenching with A O generates bromo enol acetates. 

Asymmetric hromination of ketals of alkyl aryl ketones,l a-Bromination of the ketals of alkyl aryl ketones obtained with the dimethyl esters of (2R,3R)- or (2S,3S)-tartaric acid is highly diastereoselective. Hydrolysis of the products provides optically active 2-bromo ketones. 

BH3r-BuNH2, TiO, JOC 59 705 (1994) (/J-alkoxy ketone, /l-keto ester)... 

Silyl-l,3-dienes undergo anodic methoxylation in methanol to give 1,4-addition products with an allylsilane structure as intermediates. Therefore, they are further oxidized to give l,l,4-trimethoxy-2-butene derivatives as the final products. The products are easily hydrolyzed to provide the corresponding y-methoxy-a, /t-unsaUirated aldehydes. Since 1-trimethylsilyl-l,3-dienes are readily prepared by the reaction of the anion of l,3-bis(trimethylsilyl)propene with aldehydes or ketones, l,3-bis(trhnethylsilyl)propene offers a, /i-formylvinyl anion equivalent for the reaction with carbonyl compounds (equation 15)16. 

UV spectra of a-(l,2-dithiol-3-ylidene)aldehydes or ketones [l-oxa-6,6a>S,IV-dithiapentalenes (111), X = 0] have been less systematically studied than those of 111 (X = S). Some of these data are given in Table VI. 

Haller-Bauer reaction.1 A study of the base-induced cleavage of the optically active tertiary a-phenyl ketone (l)2 shows that cleavage proceeds with retention with metal amides in benzene and alkoxides in an alcohol or benzene, but with... 

GLC can be used to monitor the disappearance of the acetylenic ketone. l-0ctyn-3-one is eluted just after a-pinene from a SE-30 6 ft column at 80°C. The checkers followed the disappearance of ketone by TLC (15% ethyl acetate in hexane). 

---