3‐Oxazolines

Gaines, Jack R.; Hansen, Gary R.

doi:10.1002/jhet.5570010209

Cited by 13 publications

(5 citation statements)

References 4 publications

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“…The reaction of a-mercapto ketones with aldoximes leads to the formation of thiazoles and water [481. The postulated in: termediate 3-hydroxy-A4-thiazoline (20) has not been isolated. The last two reactions are new thiazole syntheses.…”

Section: Syntheses With A-mercapto Ketonesmentioning

confidence: 99%

Syntheses with ketones, sulfur, and ammonia or amines at room temperature

Asinger

Offermanns

1967

Angew. Chem. Int. Ed. Engl.

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A large number oj' preparatively interesting compounds have become readily available by the simultaneous action of sulfur and amnror?ia or amines on ketones. Direct syntheses of A3-thiazolines, d3-irnidazoline-5-thiones, 5,6-dihydro-4H-1,4-thiazines, and the 1,2,3,4,5,6-hexathiocane system from ketones, sulfur, and ammonia or amines, and further possibilities for rfze synthesis of these heterocyclic systems have been proposed. Other heterocycles containing N or N and S (thiazoles, thiophenes, thiazolidines, tetrahydro-thiazol0[2,3-~]-1,4-thiazines, thiomorpholines, 4-arniizo-2H-imidazoles, etc.) are readily obtainable by further reactions of these compounds. Hydrolysis of the A3-thiazolines yieIds a-mercapto ketones, which are the starting materials for other syntheses. Most of the syntheses described proceed ut room temperature and at noririni pressure.

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Section: Syntheses With A-mercapto Ketonesmentioning

confidence: 99%

Syntheses with ketones, sulfur, and ammonia or amines at room temperature

Asinger

Offermanns

1967

Angew. Chem. Int. Ed. Engl.

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“…Origin of Compounds. The following compounds are of commercial origin and their purity was checked by 'H-or I3C-NMR prior to the I5N-NMR measurements: Fluka AG, 1-6, 17, 18,32,35,39,62,65. EGA Chemie, I , 8, 26, 33, 53.…”

Section: Three-bond N H-coupling Constantsmentioning

confidence: 99%

“…The isothiazoles 42 and 43 are commercially available, while 44 was synthesized [13b]. The syntheses and characterization of the following compounds are described under the respective references; prior to the I5N-NMR measurements the samples were checked by 'Hor I3C-NMR: 20 [32], 25, 31 [33], 30 1341, 45, 46 [351, 47 [XI, 48-59 [37], 60 [38], 61 [39], 63 1401, 64 [41],66,67 1421.…”

Section: Three-bond N H-coupling Constantsmentioning

confidence: 99%

¹⁵N‐NMR Spectra of Azoles with Two Heteroatoms

Chen

Philipsborn

Nagarajan³

1983

Helvetica Chimica Acta

105

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SummaryThe 15N-NMR spectra of azoles, with natural isotope abundance, have been measured under different experimental conditions, and chemical shifts are reported for imidazoles, pyrazoles, oxazoles, isoxazoles, thiazoles, and isothiazoles. General trends of substituent effects in this heterocyclic series are discussed based on the data of 67 substituted azoles, dihydro-and tetrahydroazoles. "N, 'H spin-coupling constants have been determined from spectra obtained by ['HI 4 I5N polarizationtransfer experiments, i.e. an application of INEPT and DEPT pulse sequences. Two-bond and three-bond coupling constants are fully assigned and are discussed in terms of the specific pathways in azoles. The potential of structural applications of the new data is illustrated for isomeric nitro-imidazoles and highly-substituted pyrazoles, and in the case of ring-chain tautomerism of 2-substituted tetrahydrooxazoles.

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“…In the Maillard reaction, α-amino carbonyls are considered precursors of not only pyrazines and/or piperazines but also of other unsaturated heterocyclic compounds, such as oxazolines [17][18][19]30,50 , oxazoles 29,30,50,51 , imidazoles [28][29][30][31]50 , imidazolines 50,52 , or pyrroles 29,30,51,53 (see Scheme 6). Nevertheless, under the reaction conditions of the reductive amination, oxazolines are unstable and react with the amination agent and hydrogen to form two molecules of corresponding α-amino alcohols 10 .…”

Section: Side Productsmentioning

confidence: 99%

“…Non-catalytic reaction of acetol with ammonia α-Hydroxy ketones react easily with ammonia even at moderate reaction conditions and without catalyst to corresponding substituted 3-oxazolines or 3,4-dihydro-2H-pyrrolenine-3,4-diols 10,[17][18][19] . The non-catalytic reaction of acetol with ammonia that leads to 2,4-dimethyl-2-(hydroxy methyl)-3-oxazoline is shown in Scheme 2 19 .…”

Section: Introductionmentioning

confidence: 99%

Reductive Amination of 1-Hydroxy-2-propanone Over Nickel and Copper Catalysts

Trégner¹

2018

Chem.Biochem.Eng.Q.

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The one-step reductive amination of 1-hydroxy-2-propanone (acetol) with ammonia to 2-aminopropanol (2-APOL) over commercial nickel and copper catalysts has been studied in the continuous fixed-bed reactor at the temperature from 130 to 220 °C and different molar ratios of reactants. It was found that the optimal molar ratios of H 2 /acetol and H 2 /NH 3 regarding the selectivity of 2-APOL were 25 and 1, respectively. The highest selectivity of approx. 45 % to desired 2-APOL at total conversion of acetol was achieved in the presence of the nickel catalyst. Major by-products of amination were cis and trans isomers of 2,5-and 2,6-dimethylpiperazines. Mechanism of the formation of these and other detected and/or potential by-products is discussed. So far, unpublished mass spectra of identified by-products, such as N-substituted dimethylpiperazines or various aminoalcohols, are reported in this paper.

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3‐Oxazolines

Abstract: α‐Hydroxy‐α‐methyl ketones react with ammonia and aromatic aldehydes in the presence of calcium chloride and ammonium chloride to yield 2‐aryl‐3‐oxazolines.

Cited by 13 publications

References 4 publications

Syntheses with ketones, sulfur, and ammonia or amines at room temperature

Syntheses with ketones, sulfur, and ammonia or amines at room temperature

¹⁵N‐NMR Spectra of Azoles with Two Heteroatoms

Reductive Amination of 1-Hydroxy-2-propanone Over Nickel and Copper Catalysts

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3‐Oxazolines

Abstract: α‐Hydroxy‐α‐methyl ketones react with ammonia and aromatic aldehydes in the presence of calcium chloride and ammonium chloride to yield 2‐aryl‐3‐oxazolines.

Cited by 13 publications

References 4 publications

Syntheses with ketones, sulfur, and ammonia or amines at room temperature

Syntheses with ketones, sulfur, and ammonia or amines at room temperature

15N‐NMR Spectra of Azoles with Two Heteroatoms

Reductive Amination of 1-Hydroxy-2-propanone Over Nickel and Copper Catalysts

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¹⁵N‐NMR Spectra of Azoles with Two Heteroatoms