Green method for preparing N-sulfimide compound

Abstract

The invention discloses a green method for preparing an N-sulfimide compound, and belongs to the technical field of green chemical synthesis. According to the method, aromatic alcohol and 4-toluene sulfonamide are taken as substrates, a low-toxicity and environment-friendly solvent is taken as a reaction medium, and the N-sulfimide compound is prepared. The N-sulfimide compound is obtained through one-step reaction, the reaction is more direct and simpler, substrate limitation is small, time is short, meanwhile, a green solvent is selected, and secondary pollution is avoided.

Description

Technical Field

[0001] The invention belongs to the technical field of green chemical synthesis, and particularly relates to a green method for preparing N-sulfonyl imide compounds. Background Art

[0002] Imines containing electron-withdrawing groups, such as N-sulfonylimines, are very important organic intermediates and chemical raw materials, widely used in industries such as pesticides, pharmaceuticals, dyes, and plastics. N-sulfonylimines are stable and easily isolated electron-deficient imines, and therefore have attracted increasing attention in recent decades. N-sulfonylimines are widely used in Diels-Alder reactions, Ene reactions, addition reactions, and free radical reactions. They are also precursors for the preparation of many practical organic compounds, such as optically active 2-imidazolines, aziridines, and the chiral oxidant N-sulfonyloxaziridine. They can also be used to synthesize Davis aziridines for various oxidation reactions.

[0003] Due to their unique role in organic synthesis, N-sulfonylimines have attracted widespread attention for their preparation. Generally speaking, direct synthesis using carbonyl compounds and sulfonamides is the simplest approach, but this requires the use of a dehydrating agent or dehydration equipment. Due to the weak nucleophilicity of N-sulfonylimines, Lewis acids are often used to enhance the reactivity of the carbonyl group, or acetals are used instead of aldehydes.

[0004] In recent years, clean production, environmental friendliness and atom economy have been advocated. Therefore, it is very meaningful to further improve the method of synthesizing N-sulfonylimine and establish a convenient, effective and green method. Summary of the Invention

[0005] Dimethyl carbonate, an organic compound with the chemical formula C3H6O3, is a low-toxic, environmentally friendly, and widely used chemical raw material, serving as an important organic synthesis intermediate. To address at least some of the aforementioned issues, the present invention discloses a green method for preparing N-sulfonylimide compounds. Compared to existing preparation methods, the present invention offers a more direct and clean reaction with minimal substrate limitations. Iodine and dimethyl carbonate are used as the catalyst and solvent, respectively, in the reaction system to avoid the use of contaminating organic solvents, thereby achieving green chemistry.

[0006] The invention discloses a green method for preparing N-sulfonyl imide compounds. The method uses aromatic alcohol and 4-toluenesulfonamide as substrates and a low-toxic and environmentally friendly solvent as a reaction medium to prepare the N-sulfonyl imide compounds.

[0007] In some embodiments of the present invention, the solvent is dimethyl carbonate.

[0008] In some embodiments of the present invention, the reaction system further includes a catalyst.

[0009] In some embodiments of the present invention, the catalyst is elemental iodine.

[0010] In some embodiments of the present invention, the aromatic alcohol is at least one of 4-nitrobenzyl alcohol, 4-methylbenzyl alcohol, 4-chlorobenzyl alcohol and furylbenzyl alcohol.

[0011] In some embodiments of the present invention, the molar ratio of the aromatic alcohol to 4-toluenesulfonamide is (1-2): (1-2).

[0012] In some embodiments of the present invention, the catalyst is 1-3 equivalents of elemental iodine.

[0013] In some embodiments of the present invention, the reaction temperature is 90-110°C.

[0014] In some embodiments of the present invention, after the reaction is completed, the organic phase is washed with water several times, separated, dried using a rotary evaporator, dried in vacuo, and purified by column chromatography.

[0015] In some embodiments of the present invention, a mixture of EtOAc and petroleum ether is used as the eluent.

[0016] In some embodiments of the present invention, a mixture of EtOA:petroleum ether (1:10, v / v) is used as the eluent.

[0017] In some embodiments of the present invention, the reaction is carried out by using aromatic alcohol and 4-toluenesulfonamide as substrates, iodine as a catalyst and oxidant, and dimethyl carbonate as a solvent, in an oxygen atmosphere at 100° C. to obtain N-sulfonylimide compounds, wherein the reaction formula is:

[0018]

[0019] Wherein: Formula 1 represents an aromatic alcohol, Formula 2 represents 4-toluenesulfonamide, and Formula 3 represents an N-sulfonimide compound;

[0020] Wherein, the aromatic alcohol is selected from one of 4-nitrobenzyl alcohol, 4-methylbenzyl alcohol, 4-chlorobenzyl alcohol and furylbenzyl alcohol;

[0021] Wherein, the catalyst and oxidant are both iodine, and the amount used is 2 equivalents;

[0022] Wherein, the solvent is dimethyl carbonate;

[0023] Wherein, the molar ratio of the aromatic alcohol 1 and 4-toluenesulfonamide 2 is 1:1;

[0024] The separation and purification method is as follows: after the reaction is completed, the organic phase is washed with water several times, separated, dried by rotary evaporator, dried by vacuum evaporator, and purified by column using EtOA: petroleum ether (1:10) as eluent to obtain the corresponding product 3.

[0025] Beneficial effects of the present invention:

[0026] The present invention realizes the one-pot reaction of 4-toluenesulfonamide and aromatic alcohol to synthesize N-sulfonyl imide compounds more directly and concisely. The reaction is more direct and concise. Aromatic alcohol is used as substrate, green iodine is used as catalytic oxidant, and dimethyl carbonate is used as solvent, which better realizes its potential green chemical value. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is the structural formula of N-(4-nitro-benzylidene)-4-methyl-benzenesulfonamide;

[0028] Figure 2 N-(4-nitro-benzylidene)-4-methyl-benzenesulfonamide prepared in Example 1 1 H NMR spectrum;

[0029] Figure 3 is the structural formula of N-(benzylidene)-4-methyl-benzenesulfonamide;

[0030] Figure 4 N-(benzylidene)-4-methyl-benzenesulfonamide prepared in Example 2 1 H NMR spectrum;

[0031] Figure 5 is the structural formula of N-(4-methyl-benzylidene)-4-methyl-benzenesulfonamide;

[0032] Figure 6 N-(4-methyl-benzylidene)-4-methyl-benzenesulfonamide prepared in Example 3 1 H NMR spectrum;

[0033] Figure 7 is the structural formula of N-(4-chloro-benzylidene)-4-methyl-benzenesulfonamide;

[0034] Figure 8 For Example N-(4-chloro-benzylidene)-4-methyl-benzenesulfonamide 1 H NMR spectrum;

[0035] Figure 9 is the structural formula of N-furan-2-methylene-4-methyl-benzenesulfonamide;

[0036] Figure 10N-furan-2-methylene-4-methyl-benzenesulfonamide prepared in Example 5 1 H NMR spectrum. DETAILED DESCRIPTION

[0037] The following describes the embodiments of the present invention through specific examples. Those skilled in the art will readily understand the other advantages and benefits of the present invention from the disclosure herein. The present invention may also be implemented or applied through various other specific embodiments, and the details in this specification may be modified or altered based on different viewpoints and applications without departing from the spirit of the present invention.

[0038] In the oxygen atmosphere described in the following examples, that is, in ordinary air, oxygen or inert gas was not increased, decreased, or controlled.

[0039] Example 1 Preparation of N-(4-nitro-benzylidene)-4-methyl-benzenesulfonamide

[0040] N-(4-nitro-benzylidene)-4-methyl-benzenesulfonamide, its structural formula is as follows Figure 1 shown.

[0041] Preparation: To a 50 mL three-necked flask, add 20 mL of dimethyl carbonate, 1 mmol of 4-nitrobenzyl alcohol, and 2 mmol of iodine. Heat to 100°C under an oxygen atmosphere for 3 h, then add 1 mmol of 4-toluenesulfonamide. Follow the reaction by thin-layer chromatography. After the reaction is complete, wash the mixture several times with water, separate the organic phase, and dry it on a rotary evaporator. After vacuum drying, purify it by column chromatography using EtOAc:petroleum ether (1:10) as the eluent to obtain N-(4-nitro-benzylidene)-4-methyl-benzenesulfonamide as a white solid with an MP of 204-205°C.

[0042] 1 H NMR (500MHz, CDCl3): δ=2.38 (s, 3H), 7.35 (d, 2H, J=8Hz), 7.44 (d, 2H, J=8Hz), 7.82 (d, 2H, J=8Hz), 8.00 (d, 2H, J=8Hz), 9.13 (s, 1H).

[0043] Example 2 Preparation of N-(benzylidene)-4-methyl-benzenesulfonamide

[0044] N-(benzylidene)-4-methyl-benzenesulfonamide, its structural formula Figure 2 shown.

[0045] Preparation: To a 50 mL three-necked flask, add 20 mL of dimethyl carbonate, 1 mmol of benzyl alcohol, and 2 mmol of iodine. Heat to 100°C under an oxygen atmosphere for 3 h, then add 1 mmol of 4-toluenesulfonamide. Follow the reaction by thin-layer chromatography. After the reaction is complete, wash the mixture several times with water, separate the organic phase, and dry it on a rotary evaporator. After vacuum drying, purify it by column chromatography using EtOAc:petroleum ether (1:10) as the eluent to obtain N-(benzylidene)-4-methyl-benzenesulfonamide as a white solid with an MP of 113-114°C.

[0046] 1 H NMR (500MHz, CDCl3): δ=2.38 (s, 3H), 7.34 (d, 1H, J=9Hz), 7.45 (d, 2H, J=8Hz), 7.55 (m, 2H), 7.83 (d, 2H, J=8Hz), 8.00 (d, 2H, J=8Hz), 9.13 (s, 1H).

[0047] Example 3 Preparation of N-(4-methyl-benzylidene)-4-methyl-benzenesulfonamide

[0048] N-(4-methyl-benzylidene)-4-methyl-benzenesulfonamide, its structural formula is as follows Figure 3 shown.

[0049] Preparation: To a 50 mL three-necked flask, add 20 mL of dimethyl carbonate, 1 mmol of 4-methylbenzyl alcohol, and 2 mmol of iodine. Heat to 100°C under an oxygen atmosphere for 3 h, then add 1 mmol of 4-toluenesulfonamide. Follow the reaction by thin-layer chromatography. After the reaction is complete, wash the mixture several times with water, separate the organic phase, and dry it on a rotary evaporator. After vacuum drying, purify it by column chromatography using EtOAc:petroleum ether (1:10) as the eluent to obtain N-(4-methyl-benzylidene)-4-methyl-benzenesulfonamide as a white solid with an MP of 130-131°C.

[0050] 1 H NMR (500MHz, CDCl3): δ=2.38 (s, 3H), 3.90 (s, 3H), 7.34 (d, 2H, J=8Hz), 7.69 (d, 2H, J=8Hz), 7.83 (d, 2H, J=8Hz), 8.00 (d, 2H, J=8Hz), 9.01 (s, 1H).

[0051] Example 4 Preparation of N-(4-chloro-benzylidene)-4-methyl-benzenesulfonamide

[0052] N-(4-chloro-benzylidene)-4-methyl-benzenesulfonamide, its structural formula is as follows Figure 4 shown.

[0053] Preparation: To a 50 mL three-necked flask, add 20 mL of dimethyl carbonate, 1 mmol of 4-chlorobenzyl alcohol, and 2 mmol of iodine. Heat to 100°C under an oxygen atmosphere for 3 h, then add 1 mmol of 4-toluenesulfonamide. Follow the reaction by thin-layer chromatography. After the reaction is complete, wash the mixture several times with water, separate the organic phase, and dry it on a rotary evaporator. After vacuum drying, purify it by column chromatography using EtOAc:petroleum ether (1:10) as the eluent to obtain N-(4-chloro-benzylidene)-4-methyl-benzenesulfonamide as a white solid with an MP of 180-182°C.

[0054] 1 H NMR (500MHz, CDCl3): δ=2.38 (s, 3H), 7.34 (d, 2H, J=9Hz), 7.45 (d, 2H, J=8Hz), 7.82 (d, 2H, J=8Hz), 7.96 (d, 2H, J=8Hz), 9.13 (s, 1H).

[0055] Example 5 Preparation of N-furan-2-methylene-4-methyl-benzenesulfonamide

[0056] N-furan-2-methylene-4-methyl-benzenesulfonamide, its structural formula is as follows Figure 5 shown.

[0057] Preparation: To a 50 mL three-necked flask, add 20 mL of dimethyl carbonate, 1 mmol of furanylmethanol, and 2 mmol of iodine. Heat to 100°C under an oxygen atmosphere for 3 h, then add 1 mmol of 4-toluenesulfonamide. Follow the reaction by thin-layer chromatography. After the reaction is complete, wash the mixture several times with water, separate the organic phase, dry it on a rotary evaporator, and then purify it by column chromatography using EtOAc:petroleum ether (1:10) as the eluent to obtain N-furan-2-methylene-4-methyl-benzenesulfonamide as a white solid with an MP of 99-101°C.

[0058] 1 H NMR (500MHz, CDCl3): δ=2.38 (s, 3H), 7.34 (d, 1H, J=8Hz), 7.45 (d, 2H, J=8Hz), 7.82 (d, 2H, J=8Hz), 8.00 (d, 2H, J=8Hz), 9.25 (s, 1H).

[0059] The preferred specific implementation modes and embodiments of the present invention are described in detail above, but the present invention is not limited to the above implementation modes and embodiments. Various changes can be made within the scope of knowledge possessed by those skilled in the art without departing from the concept of the present invention.

Claims

1. A green method for preparing N-sulfonyl imide compounds, characterized in that: N-sulfonylimide compounds are prepared using aromatic alcohols and 4-toluenesulfonamide as substrates and low-toxic, environmentally friendly solvents as reaction media.

2. The method according to claim 1, characterized in that The solvent is dimethyl carbonate.

3. The method according to claim 1 or 2, characterized in that The reaction system also includes a catalyst.

4. The method according to any one of claims 1 to 3, characterized in that: The catalyst is elemental iodine.

5. The method according to any one of claims 1 to 4, characterized in that: The aromatic alcohol is at least one of 4-nitrobenzyl alcohol, 4-methylbenzyl alcohol, 4-chlorobenzyl alcohol and furylbenzyl alcohol.

6. The method according to any one of claims 1 to 5, characterized in that: The molar ratio of the aromatic alcohol to 4-toluenesulfonamide is (1-2): (1-2).

7. The method according to any one of claims 1 to 6, characterized in that: The catalyst is 1-3 equivalents of elemental iodine.

8. The method according to any one of claims 1 to 7, characterized in that: The reaction temperature is 90-110°C.

9. The method according to any one of claims 1 to 8, characterized in that: After the reaction is completed, the organic phase is separated after washing with water several times, dried by rotary evaporator, vacuum dried, and purified by column.

10. The method according to any one of claims 1 to 9, characterized in that: A mixture of EtOAc and petroleum ether was used as the eluent.

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