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Facile transformation

A study that shows that a chemical that has bioaccumulated or is widespread in the environment and is capable of easily breaking down into one or more chemicals associated with known risks is reportable. The text of the 2003 Guidance does not require that a chemical be widespread in the environment or that it has bioaccumulated before facile transformation to a chemical with known risks is reportable. Logically, if the chemical were not in the environment the fact of facile transformation would not be related to an environmental effect, however. [Pg.254]


Treatment of 7r-allylpalladium chloride with CO in EtOH affords ethyl 3-butenoate (321)[284]., 3, y-Unsaturated esters, obtained by the carbonylation of TT-allylpalladium complexes, are reactive compounds for 7r-allyl complex formation and undergo further facile transformation via 7r-allylpalladium complex formation. For example, ethyl 3-butenoate (321) is easily converted into 1-carboethoxy-TT-allylpalladium chloride (322) by the treatment with Na PdCL in ethanol. Then the repeated carbonylation of the complex 322 gives ethyl 2-... [Pg.64]

The intervention of mesoionic intermediates is suggested by the facile transformation of steroidal dienones, and by a number of acid-catalyzed nonphotolytic reactions which either parallel the photoisomerizations or correlate photoproducts from reactions in protic and aprotic solvents. The isomerization (175) -> (176) -l- (177) has also beeen achieved in the dark by acetic and formic acid catalysis and clearly involves the conjugate acid of the proposed mesoionic intermediate (199) in the dark reaction. Further,... [Pg.332]

The mechanism for the transformation of 5 to 4 was not addressed. However, it seems plausible that samarium diiodide accomplishes a reduction of the carbon-chlorine bond to give a transient, resonance-stabilized carbon radical which then adds to a Smni-activated ketone carbonyl or combines with a ketyl radical. Although some intramolecular samarium(n)-promoted Barbier reactions do appear to proceed through the intermediacy of an organo-samarium intermediate (i.e. a Smm carbanion),10 ibis probable that a -elimination pathway would lead to a rapid destruction of intermediate 5 if such a species were formed in this reaction. Nevertheless, the facile transformation of intermediate 5 to 4, attended by the formation of the strained four-membered ring of paeoniflorigenin, constitutes a very elegant example of an intramolecular samarium-mediated Barbier reaction. [Pg.638]

A similar intramolecular nucleophilic capture of an allylic sulfenate generated thermally from the corresponding sulfoxide was also reported for the facile transformation of the azetidinone 61 into a new 3-acetylthio-2-thiacephem ring system 62 (equation 29)127. [Pg.733]

Sletzinger, M., Lin, T., Reamer, R.A., Shinkai, 1. (1980) A Facile Transformation of BicycUc Keto Esters to Bisprotected ( )-8-Epithienamycin Via Enol Activation. Tetrahedron Letters, 21, 4221M224. [Pg.198]

Attitude to Metalation and to the Facile Transformation into / CFPs Nanocomposites... [Pg.203]

The regioselective ring opening of the silyl epoxides is facilitated by the stabilizing effect that silicon has on a positive charge in the -position. This facile transformation permits vinylsilanes to serve as the equivalent of carbonyl groups in multistep synthesis.149... [Pg.1114]

In recent years, the emphasis of research has been directed more and more toward utilizing nitro compounds as reactive intermediates in organic synthesis. The activating effect of the nitro group is exploited in carrying out many organic reactions, and its facile transformation into various functional groups has broadened the importance of nitro compounds in the synthesis of complex molecules. [Pg.380]

H. Kotsuki, T. Shimanouchi, R. Ohshima, and S. Fujiwara, Solvent-free organic reactions on silica gel supports. Facile transformation of epoxides to /i-halohy-drins with lithium halides, Tetrahedron, 54 (1998) 2709-2722. [Pg.86]

Exchange of the butyl vinyl ether for 2-hydroxyethyl vinyl ether enabled the facile transformation of vinyl triflates or bromides into protected a,/i-unsaturated methyl ketones (Eq. 11.14) [27]. One interesting aspect of this reaction is that a masked methyl ketone can easily be introduced into a structure even in the presence of other free ketone groups. [Pg.387]

Various heteroarylenenamines were starting materials in the synthesis of pyridine derivatives. For example, 3-dimethylaminomethylenoxyindole derivatives (168) were used in the preparation of a-carbolines (95MC226). Indolylenamines (169) undergo a facile transformation into y-carbolines... [Pg.319]

An important current stimulus to studies of metal carbonyl chemistry revolves around the need to develop new and efficient procedures for the facile transformation of CO into hydrocarbons and organic chemicals, and to understand the ways in which existing catalyzed reactions occur. Such conversions, which are discussed more fully under the section on CO reduction, are of key importance in utilizing coal more effectively in the nation s energy program. [Pg.84]

The salient feature of le as a chiral phase-transfer catalyst is its ability to catalyze the asymmetric alkylation of glycine methyl and ethyl ester derivatives 4 and 5 with excellent enantioselectivities. Since methyl and ethyl esters are certainly more susceptible towards nucleophilic additions than tert-butyl ester, the synthetic advantage of this process is clear, and highlighted by the facile transformation of the alkylation products (Scheme 5.3) [8],... [Pg.74]

The synthetic utility of this cascade reaction was underscored by the facile transformation of crotyl tiglate into 1,3-diol 137 (Scheme 7.39).82 Silver-catalyzed silylene transfer to crotyl tiglate produced silalactone 136 nearly quantitatively as a 97 3 mixture of diastereomers. Diol 137 was generated from silalactone after reduction of the lactone moiety with lithium aluminum hydride followed by oxidation of the C-Si bond 65>66 81... [Pg.209]

The ruthenium cluster Ru3(CO)12 and the RuCl2(CO)2(PPh3)2 system with ethyl or methyl iodide and additionally with diethyl amine as cocatalyst(s) have shown high catalytic activity in facile transformation of cyclic and acyclic amides to amines via hydrosilylation with many trisubstituted silanes (Eq. 94) [149],... [Pg.233]

The /V-phenylselenophthalimide (NPSP)-tributylphosphine (Bu3P) system is also a useful reagent for the facile transformation of carboxylic acids into seleno esters, and of alcohols into alkyl phenyl selenides (including some carbohydrate derivatives).102 The utility of iV-phenylselenophthalimide (N-PSP) as a selenylating agent has been reviewed by Nicolaou and co-workers.103... [Pg.184]

The dialdehyde 236, dissolved in water, immediately and exclusively formed a dihydrate, which gave the spiro-fused oxazocine 147b in a moderately facile transformation (/1/2 2h at 23°C) that likely proceeded through the bridged hydrate 237 as a transient intermediate (Scheme 50) <2000T9885>. [Pg.218]

Since 2002 a European consortium has dealt with the transfer of a pilot-scale Halo-clean rotary kiln system to technical scale (Figure 20.2). By scaling up the pilot-scale unit with a throughput of about 40 kg/h, a technical scale with a feed of up to 3000 t/a will be realized. The Haloclean process, combined with its post-treatment facilities transforms electronic scrap into three typical fractions, residues containing metals, precious metals, carbon, glass and inerts, as well as phenolic-based oils and HBr [11, 51, 56-59]. [Pg.559]

As an electrochemical reaction, Torii and co-workers demonstrated that the facile transformation of alkenes into allylic alcohols and ethers proceeded in the presence of a catalytic amount (10 mol%) of diphenyl diselenide (Scheme 15) [18]. Most of terminal co double bonds of isoprenoids undergo regioselective oxyselenenylation-deselenenylation to give frans-allylic alcohols in aqueous acetonitrile and methyl ethers in methanol. The addition of SOI salts improves chemical yields since SOI salts prevent the conversion of phenylselenenic acid (PhSeOH) into the inert phenylseleninic acid (PhSe02H) by both disproportionation and electro-oxidation. This method was also applied to intramolecular reaction to form -lactone in high yield. [Pg.246]

The oxidation of sulfides to sulfoxides is a facile transformation for which many reagents have been employed in the literature. These include hydrogen peroxide, ozone, nitric acid, chromic acid or tert-butylhypochlorite. Here, meto-chloroperbenzoic acid is used to oxidize a-phenylthio ketone 14, and successive elimination of the resulting a-phenylsulfinyl ketone 15 by heating at reflux in benzene provides the or,ji3-unsaturated ketone 16. Because of their thermal instability sulfoxides easily undergo elimination. The mechanism is explained by Cram as stereospecific cw-elimination. ... [Pg.61]

In 1913, Kishner observed in one instance that under standard Wolff-Kishner reduction conditions, 2-hydroxy-2,6-dimethyloctan-3-one underwent eliminative reduction upon treatment with hydrazine hydrate and base at elevated temperatures to afford 2,6-dimethyloctan-2-ene (Scheme 7). This same reaction was later found to occur in the case of a-methoxy ketones and has since been referred to as the Kishner eliminative reduction. The reaction entails initial formation of the hydrazone and elimination of the a-substituent to afford the intermediate alkenyldiazene, which subsequently collapses to the desired alkene. Given the facile transformation of ketones into a-halo ketones, these conditions have been used to introduce alkenes regioselectively in the 2a-halocholestan-3-one series as shown in Scheme 8. Yields of 2-cholestene parallel the resistance of the a-halogen to undergo competitive elimination reactions. [Pg.926]

Raphael et al made use of this facile transformation for the synthesis of the allene acetate (12), hydrolyzed by mild acid treatment to the j8-unsaturated aldehyde. [Pg.1381]

A major advantage of the macrocyclic dienones obtained from building blocks described herein is the extensive potential for facile transformations that can... [Pg.229]

Open-shell cobalt(III) imido complex [Co=NAd(TptBu,Me)] is a stable representative of a broader class of multiply bonded terminal [Co=X(Tpx)j species (for example, X = NR) the existence of [Co=NAd(Tp Bu Me)] suggests that other isoelectronic embodiments (X = O, S, PR, CR2) may also be accessible and possess some — albeit fleeting — stability. Nevertheless, the facile transformation of [Co=NAd(Tp Bu,Me)] by a C-H activation into the complex III in Fig. 3.14 demonstrates the inherent reactivity of these compounds.93... [Pg.295]


See other pages where Facile transformation is mentioned: [Pg.140]    [Pg.377]    [Pg.534]    [Pg.174]    [Pg.140]    [Pg.340]    [Pg.156]    [Pg.451]    [Pg.61]    [Pg.702]    [Pg.372]    [Pg.114]    [Pg.1767]    [Pg.6567]    [Pg.140]    [Pg.741]    [Pg.71]    [Pg.56]    [Pg.87]    [Pg.765]    [Pg.41]    [Pg.153]   
See also in sourсe #XX -- [ Pg.254 , Pg.755 ]




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