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N-propionyl

Chiral 2-oxazolidones are useful recyclable auxiliaries for carboxylic acids in highly enantioselective aldol type reactions via the boron enolates derived from N-propionyl-2-oxazolidones (D.A. Evans, 1981). Two reagents exhibiting opposite enantioselectivity ate prepared from (S)-valinol and from (lS,2R)-norephedrine by cyclization with COClj or diethyl carbonate and subsequent lithiation and acylation with propionyl chloride at — 78°C. En-olization with dibutylboryl triflate forms the (Z)-enolates (>99% Z) which react with aldehydes at low temperature. The pure (2S,3R) and (2R,3S) acids or methyl esters are isolated in a 70% yield after mild solvolysis. [Pg.61]

One of the simplest ways to prepare a chitin gel is to treat chitosan acetate salt solution with carbodiimide to restore acetamido groups. Thermally not reversible gels are obtained by AT-acylation of chitosans N-acetyl-, N-propionyl- and N-butyryl-chitosan gels are prepared using 10% aqueous acefic, propionic and bufyric acid as solvents for treatment with appropriate acyl anhydride. Both N- and 0-acylation are found, but the gelation also occurs by selective AT-acylation in the presence of organic solvents. [Pg.180]

The N-propionyl-5,5-dimethyl-4-methylene-l,3-oxazolidin-2-one, the ruthenium catalyst and methanol (10 mL) were placed in the autoclave under nitrogen atmosphere. [Pg.189]

Conversion of 2 to the highly crystalline oxazolidinone 3 with phosgene has been described by Thornton who has employed this substance as a chiral auxiliary in asymmetric aldol reactions of its N-propionyl derivative. Kelly has also used an oxazoline derived from 3 as a chiral auxiliary in asymmetric alkylation of a glycolate enolate. Oxazolidinone 3 has also been prepared from 2 with diethyl carbonate in the presence of potassium carbonate. The conversion of 2 to the oxazolidinone 3 is accomplished using triphosgene in this procedure because of the high toxicity of phosgene. [Pg.216]

Sd Hu 082 Pyrrole, N-metbyl Sd Pyrrole, N-metbyl-2-acetyl Sd Pyrrole, N-N-pentyl Sd Pyrrole, N-propionyl Sd Pyrrole Sd (roasted) ... [Pg.161]

Pathway of Methyl propionate Formation from the Alkaline Degradation of N-Propionyl-N-nitrosourea proposed by Kirmse (28)... [Pg.70]

Some species of cellular slime molds use other chemical attractants (acrasins). For example, D. minutum secretes an analog of folic acid1 and cells of Polysphondylium violaceum are attracted by the ethyl ester of N-propionyl-y-L-glutamyl-L-ornithine-8-lactam.s... [Pg.557]

The life cycle of Dictyostelium discoideum is described briefly in Box 11-C. About 105 individual amebas aggregate to form a moving "slug" in response to the chemoattractant cAMP. Some other species of Dictyostelium are attracted to a folic acid derivative or to the ethyl ester of N-propionyl-y-L-glutamyl-L-omithine-5-lactam 226... [Pg.1892]

The N-benzoyl methyl ester of Gly has been analysed on QF-1 [242] and N-benzyl-oxycarbonyl methyl and ethyl esters and N-palmitoyl ethyl esters of Leu on SE-30 [243]. N-Propionyl isoamyl derivatives of fourteen amino acids were prepared by allowing isoamyl esters to react with propionyl chloride and were also analysed on QF-1 and applied to the analysis of amino acids in bacterial cultures [244]. [Pg.136]

Ghosh et al. reported that the chiral oxazolidinone 87, derived from (1S,2R)-cis-l-amino-2-indanol (86), underwent a highly diastereoselective. vyn-aldol reaction with a variety of aldehydes30 (Scheme 2.1cc). Reaction of the indanolamine 86 with disuccinyl carbonate in acetonitrile gave the oxazolidinone 87, which was deprotonated with -BuLi and reacted with propionyl chloride to provide the N-propionyl derivative 88. Reaction of 88 with n-BioBOTf and... [Pg.75]

There are many other questions that need to be addressed. For example What are the kinetics of the inhibition Do the different inhibitors bind at the same site What are the molecular requirements for inhibition What are the differences between susceptible and tolerant ACCases and so on. ACCase purified 40 to 100 fold may not be sufficiently pure to answer many of these questions. For example, an extract purified on a Sephacryl S-300 column can have a specific activity up to 400 nmol/min/mg. We have observed that this preparation can catalyze the carboxylation of other short chained acyl CoA s in addition to acetyl CoA (Table VI). Both haloxyfop and tralkoxydim inhibit the carboxylation reaction regardless of whether n-propionyl CoA or acetyl CoA are substrates either individually or together (Table VII). At present, we are unsure whether n-propionyl CoA can be used as a substrate for ACCase or whether a n-propionyl CoA carboxylase is present in the preparation and the herbicides also inhibit that enzyme. [Pg.266]

Table VII. Effect of Haloxyfop and Tralkoxydim on the Carboxylation of Acetyl CoA and n-Propionyl CoA... Table VII. Effect of Haloxyfop and Tralkoxydim on the Carboxylation of Acetyl CoA and n-Propionyl CoA...
Like 2-amino-2-deoxy-D-glucose, 2-acetamido-l-(L-aspart-4-oyl)-2-deoxy-jS-D-glucopyranosylamine was a noninhibitor of both hemagglutination128 and precipitation.498 These data suggest that an uncharged amide group (for example, N-acetyl or N-propionyl group)... [Pg.218]

As above (eq 1), a major drawback of this reagent is the lack of a readily available enantiomer. There are many alternative methods for the enantioselective propionate aldol reaction. The most versatile chirally modified propionate enolates or equivalents are N-propionyl-2-oxazolidinones, a-siloxy ketones, boron enolates with chiral ligands, as well as tin enolates. Especially rewarding are new chiral Lewis acids for the asymmetric Mukaiyama reaction of 0-silyl ketene acetals. Most of these reactions afford s yw-aldols good methods for the anri-isomers have only become available recently. ... [Pg.190]


See other pages where N-propionyl is mentioned: [Pg.322]    [Pg.1312]    [Pg.175]    [Pg.189]    [Pg.189]    [Pg.78]    [Pg.137]    [Pg.248]    [Pg.343]    [Pg.19]    [Pg.129]    [Pg.1892]    [Pg.322]    [Pg.151]    [Pg.48]    [Pg.458]    [Pg.2883]    [Pg.286]    [Pg.286]    [Pg.188]    [Pg.188]    [Pg.83]    [Pg.266]    [Pg.268]    [Pg.268]    [Pg.288]    [Pg.471]    [Pg.487]   


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HA inhibitors 5-N-propionyl-Neu

Propionylation

Synthesis of (R)-N-propionyl-4,5,5-trimethyl-l, 3-oxazolidin-2-one

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