The Action of N-Bromosuccinimide on β-Phenyl-α,β-unsaturated Ketones. II. The Bromination of Benzyl Styryl Ketone

Southwick, Philip L.; Pursglove, L. A.; Numerof, Paul

doi:10.1021/ja01160a049

Cited by 12 publications

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“…The spectra of the 2-and 4styrylpyridines (stilbazoles), it may be mentioned, are also similar to the spectrum of irans-stilbene (9). All of the 4-styrylthiazoles described here are probably of the írans-configuration; degradations of the parent halo ketones la and Ic have yielded frans-cinnamic acid (1,10). Since there is a strong band at 292 µ in the spectrum of 2-methyl-4-styrylthiazole (lib), whereas the principal maxima in styrene ( 244 µ; log c 4.23) (11) or /3-methylstyrene (X 246 m/u; log e 4.25) (11) and in 2-methylthiazole (X 244 m/u; log e 4.34) are at much shorter wave lengths, it is clear that in compound lib there is effective conjugation between the styryl group and the thiazole ring.…”

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confidence: 76%

“…Three halogenated ketones, one derived from benzalacetone and two derived from benzyl styryl ketone, were used in the synthesis of the 4-styrylthiazoles (II). The conversion of benzalacetone into iodomethyl styryl ketone (la) and of benzyl styryl ketone into 1 -bromo-1,4-diphenyl-3-buten-2-one (lb) have been described previously (1). The third halo ketone, 1-iodo-l ,4-diphenyl-3-buten-2one (Ic), was prepared by treatment of a direct bromination product of benzyl styryl ketone, 1,3,4-tribromo-l, 4-diphenyl-2-butanone, with excess sodium iodide in acetone solution.…”

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confidence: 99%

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4-Styrylthiazoles. Syntheses and Relationships Among Ultraviolet Absorption Spectra

Southwick¹,

Sapper²

1954

J. Org. Chem.

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the type I (1). These halo ketones have been found to react with thioamides and related compounds, apparently without complication due to the conjugated unsaturation, to yield the 4-styrylthiazoles (II). The latter compounds may be regarded as analogs of stilbene derivatives. Stilbene derivatives and such stilbene analogs as styryl derivatives of pyridine, benzoquinoline, benzothiazole, and acridine have been studied as growth inhibitors and carcinogenic agents (2); the styrylthiazoles described here may be of interest in the same connection. Numerous 2-styrylthiazoles are known, but 4or 5-styrylthiazoles, in which the carbon to carbon double bond of the thiazole ring is conjugated directly with the styryl group, have apparently not been reported previously. A report of the preparation of 5-styrylthiazole (3) was later found to be in error (4).The ultraviolet absorption spectra of these compounds, most of which show two or more strong bands, afford an opportunity to compare effects produced by a variety of substituent groups (phenyl, methyl, amino, hydroxyl, mercapto) with effects due to corresponding groups in derivatives of aromatic hydrocarbons. It has been found that spectral effects in this 4-styrylthiazole series can often be predicted remarkably well from relationships which have been found to hold among derivatives of quite a different family of compounds, the polynuclear aromatic hydrocarbons, which have been chosen for comparison here

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confidence: 76%

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confidence: 99%

4-Styrylthiazoles. Syntheses and Relationships Among Ultraviolet Absorption Spectra

Southwick¹,

Sapper²

1954

J. Org. Chem.

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“…IR (NaCl, ν max , cm –1 ): 1640, 1573, 1438, 1270, 1072, 990, 874, 803, 764, 704. Mp: 57 °C (lit . mp 56.5–58.5 °C).…”

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confidence: 99%

“…30 Following the general procedure, starting from (2E)-N-methoxy-N-methyl-3-phenylacrylamide (1e) (0.27 g, 1.43 mmol), CH 2 Br 2 (990 mg, 0.40 mL, 5.7 mmol), and MeLi-LiBr (2.85 mL, 4.28 mmol) in THF, αbromoketone 3b was obtained in 89% yield (0.29 g) as a pale yellow solid. 1 (3E)-1-Iodo-4-phenyl-3-buten-2-one (3c): 31 Following the general procedure, starting from (2E)-N-methoxy-N-methyl-3-phenylacrylamide (1e) (0.27 g, 1.43 mmol), CH 2 I 2 (1.53 g, 0.46 mL, 5.7 mmol), and MeLi-LiBr (2.85 mL, 4.28 mmol) in THF, α-iodoketone 3c was obtained in 92% yield (0.36 g) as a pale yellow solid. 1 32 To a solution of ethyl cinnamate (176 mg, 1.0 mmol) in THF (3 mL) cooled at −78 °C was added chloroiodomethane (317 mg, 1.8 mmol, 0.13 mL) and, after 2 min, MeLi−LiBr ethereal solution (1.5 M, 1.8 mmol, 1.20 mL).…”

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Synthesis of α,β-Unsaturated α′-Haloketones through the Chemoselective Addition of Halomethyllithiums to Weinreb Amides

2013

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A straightforward synthesis of variously functionalized α,β-unsaturated α'-haloketones has been achieved through the chemoselective addition of halomethyllithium carbenoids to Weinreb amides at -78 °C. A comparative study employing the corresponding esters under the same reaction conditions pointed out that the instability of the tetrahedral intermediate formed from the latter is responsible for the observed formation of carbinols instead of the desired haloketones.

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The Aldol Condensation

Nielsen

Houlihan²

2011

Organic Reactions

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The aldol condensation takes its name from aldol (3‐hydroxybutanal) a name introduced by Wurtz who first prepared the beta‐hydroxy aldehyde from acetaldehdye in 1872. The aldol condensation includes reactions producing beta‐hydroxy aldehydes or beta‐hydroxy ketones by self condensations or mixed condensations of aldehydes and ketones as well as reactions leading to alpha, beta‐unsaturated aldehydes or alpha,beta‐unsaturated ketones formed by dehydration of intermediate beta‐aldols or beta‐ketals. The Claisen‐Schmidt condensation is most often taken to be the condensation of an aromatic aldehyde or ketone usually in the presence of a basic catalyst. The term aldol condensation has also been applied to many other condensations involving the reaction of an aldehyde or ketone. These condenations are discussed. The present review includes examples that are solely condensation reactions of aldehydes and ketones.

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The Action of N-Bromosuccinimide on β-Phenyl-α,β-unsaturated Ketones. II. The Bromination of Benzyl Styryl Ketone

Cited by 12 publications

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4-Styrylthiazoles. Syntheses and Relationships Among Ultraviolet Absorption Spectra

4-Styrylthiazoles. Syntheses and Relationships Among Ultraviolet Absorption Spectra

Synthesis of α,β-Unsaturated α′-Haloketones through the Chemoselective Addition of Halomethyllithiums to Weinreb Amides

The Aldol Condensation

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