- Method for synthesizing alpha-fluorinated ketone through hydrazone aliphatic chain monoketone
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The invention belongs to the technical field of organic synthesis, and provides a method for synthesizing alpha-ketone fluoride through hydrazone aliphatic chain monoketone, which comprises the following steps of: reacting aliphatic chain monoketone with hydrazine hydrate to obtain hydrazone, and reacting hydrazone with a compound represented by formula 2 under a heating condition to complete hydrazone defluorination. The fluorinated product is widely applied to medicines, the reaction conditions are mild, and the process is simple.
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Paragraph 0071-0073
(2021/02/06)
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- 1-Haloalkyl Aryl Sulfoxides as Useful Agents in Synthesis of α-Halo Ketones: A New Synthesis of α-Halo Ketones, α-Halo α,β-Unsaturated Ketones, and α-Halo Cross Dienones from Aldehydes
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α-Halo α-sulfinyl ketones were synthesized in two steps from 1-haloalkyl aryl sulfoxides and aldehydes in high yields.Desulfinylation of the α-halo α-sulfinyl ketones was performed with ethylmagnesium bromide in ether at low temperature to afford α-halo ketones via magnesium enolates in high yields.The magnesium enolate intermediates were trapped with various electrophiles such as deuterium oxide, ethyl chloroformate, and chlorotrimethylsilane.Trapping of the magnesium enolate intermediate with carbonyl compounds afforded a new type of the directed aldol reaction.Desulfi nylation of the sulfinyl group of the α-halo α-sulfinyl ketones under thermal conditions gave α-halo α,β-unsatureted ketones or α-halo cross dienones.
- Satoh, Tsuyoshi,Itoh, Norifumi,Onda, Ken-ichi,Kitoh, Yasushi,Yamakawa, Koji
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p. 2800 - 2806
(2007/10/02)
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- ETHYLMAGNESIUM BROMIDE MEDIATED DESULFINYLATION OF α-HALO-β-KETOSULFOXIDES GIVING α-HALOKETONES, AND TRAPPING OF THE MAGNESIUM ENOLATE INTERMEDIATE
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Treatment of α-halo-β-ketosulfoxides with EtMgBr gives α-haloketones in high yields after protonation of the magnesium enolates.Trapping of the magnesium enolates with various electrophiles is also carried out.
- Satoh, Tsuyoshi,Onda, Ken-ichi,Itoh, Norifumi,Yamakawa, Koji
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p. 5599 - 5600
(2007/10/02)
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- Photoreactivity of α-Fluorinated Phenyl Alkyl Ketones
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The photoreactivities of the mono-, di-, and tri-α-fluorinated acetophenones have been compared to that of acetophenone itself.All four ketones have similar triplet excitation energies; the three fluorinated ketones have reduction potentials 0.5-0.7 eV lower than that of acetophenone.Triplet reactivity toward alkylbenzenes keeps increasing with fluorine substitution, Since the rate-determining step becomes charge-transfer complexation as the ketone reduction potential decreases.The primary/tertiary C-H selectivity toward p-cymene increases with the number of fluorines.Triplet reactivity toward cyclopentane also is increased by fluorination but peaks at two fluorines, since the lowest triplet switches from n,?* to ?,?* with two or three fluorines and ?,?*triplets are unreactive in simple hydrogen atom abstraction.In contrast, α-fluorination of valerophenone does not significantly increase the rate of triplet γ-hydrogen abstraction.The inductive effect on reactivity apparently is offset by a conformational effect.Th α-fluorinated phenones give predominantly cyclobuthanols instead of Norrish type II elimination. α-fluoroacetophenone forms predominantly acetophenone and HF when irradiated with 2-propanol, in what appears a short chain process involving electron transfer to ketone followed by fluoride ion loss.Finally, the radical coupling products in these reactions are formed in varying yields, depending on solvent and additives.It is suggested that radical solvation can affect radical coupling rates sufficiently to prevent statistical ratios of cross-coupling and homo-coupling.
- Wagner, Peter J.,Thomas, Michael J.,Puchalski, Allen E.
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p. 7739 - 7744
(2007/10/02)
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- REGIOSPECIFIC SYNTHESIS OF α-KETOACETALS BY REARRANGEMENT OF α-BROMO-α-FLUOROKETONES
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α-Ketoacetals, derived from alkylaryl-α-diones and with acetalized benzoyl moiety, were synthesized by alkoxide induced rearrangement of α-bromo-α-fluoroalkylarylketones.
- Kimpe, Norbert De,Verhe, Roland,Buyck, Laurent De,Schamp, N.
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p. 2257 - 2260
(2007/10/02)
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