N-demethylation method for amide and application thereof
A demethylation and amide technology, applied in the field of amide N-demethylation, can solve problems such as few methods for amide N-demethylation, and achieve easy operation, low cost and mild reaction conditions. Effect
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[0017] A typical embodiment of the present invention provides a method for N-demethylation of amides. The raw material amides are heated to 40-120°C under the action of N-fluorobisbenzenesulfonamide and divalent copper salt, Reaction to obtain demethylated amides;
[0018] The chemical structural formula of raw material amide is
[0019] The chemical structure of demethylated amides is
[0020] Among them, R 1 selected from aryl, alkyl, alkenyl, R 2 selected from aryl, alkyl, alkenyl.
[0021] N-fluorobisbenzenesulfonamide is a kind of oxidizing agent, yet found through experiment, when adopting hydrogen peroxide (H 2 o 2 ) and other oxidants cannot achieve the N-demethylation of amides.
[0022] In one or more examples of this embodiment, the molar ratio of raw material amide to N-fluorobisbenzenesulfonamide is 1:1-3. It is found through experiments that, compared with other proportions, the N-demethylation effect of the amides of this proportion is better. When t...
Embodiment 1
[0035] In a dry pressure vessel with a magnetic stirring bar, 0.4 mmol of N-methyl-N-phenylmethacrylamide (1a), 0.6 mmol of NFSI, and 0.04 mmol of copper acetylacetonate were successively added. Measure and add 1.2 mmol (49 μL) of methanol with a pipette gun, and then add 1 mL of acetonitrile with a syringe. in N 2 Under the atmosphere, the temperature of the oil bath was adjusted to 80° C., and the reaction was stirred for 24 h. After the completion of the reaction was determined by thin-plate chromatography, the concentrated reaction mixture was separated with a silica gel column using a mixture of petroleum ether and ethyl acetate as the mobile phase to obtain the demethylated amide (2a).
[0036]
[0037] 2a
[0038] N-phenylmethacrylamide:
[0039] 1 H NMR (400MHz, CDCl 3 )δ7.56(d, J=8.0Hz, 3H), 7.33(t, J=8.0Hz, 2H), 7.12(t, J=7.2Hz, 1H), 5.79(s, 1H), 5.45(s, 1H), 2.06(s, 3H).
[0040] 13 C NMR (100MHz, CDCl 3 )δ166.6, 140.9, 137.8, 128.9, 124.4, 120.0, 119.7,...
Embodiment 2
[0043] In a dry pressure vessel with a magnetic stirring bar, 0.4 mmol of N-methyl-N-phenylmethacrylamide, 1.2 mmol of NFSI, and 0.04 mmol of copper acetylacetonate were successively added. Measure and add 1.2 mmol (49 μL) of methanol with a pipette gun, and then add 1 mL of acetonitrile with a syringe. in N 2 Under the atmosphere, the temperature of the oil bath was adjusted to 80° C., and the reaction was stirred for 24 h. After the completion of the reaction was determined by thin plate chromatography, the filtrate was concentrated and the reaction mixture was separated with a silica gel column using a mixture of petroleum ether and ethyl acetate as the mobile phase to obtain demethylated amide.
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