Добрый день!
Уважаемые коллеги, подскажите, кто знает, где подсмотреть методики селективного восстановления нитроазоаренов до аминоазоаренов соответсвенно?
+++Селективное восстановление нитроазоаренов
+++Селективное восстановление нитроазоаренов
Последний раз редактировалось bai Вс июн 27, 2021 3:43 pm, всего редактировалось 2 раза.
Re: Селективное восстанрвление нитроазоаренов
по моему это фигвам , пару месяцев назад интересовался по диагонали, не нашел методик, в итоге пошли другим путем -были альтернативы вставить амин в алифатическую цепочку через N-Boc protected , но если бы пробовал ,наверное начал бы с Na2S*9H2O
он химик, он ботаник-князь Федор , мой племянник
Re: Селективное восстанрвление нитроазоаренов
Ну да, во многих книжках написано, что сульфид работает именно так, но ни методик, ни ссылок нет
Re: Селективное восстанрвление нитроазоаренов
а фенола в системе там нигде нет ? 
он химик, он ботаник-князь Федор , мой племянник
Re: Селективное восстанрвление нитроазоаренов
А что такое аминоазоарен ?
Если это аминопроизводное азоарена или диарилтриазен, то непонятно, откуда возьмется третий азот.
Если это аминопроизводное азоарена или диарилтриазен, то непонятно, откуда возьмется третий азот.
Re: Селективное восстанрвление нитроазоаренов
аминопроизводное азоарена, которое было получено восстановлением нитрогруппы в соответствующем нитроазоарене
Re: Селективное восстанрвление нитроазоаренов
Chemistry of Materials (2014), 26, (17), 5089-5096 :
Synthesis of 3-(phenyldiazenyl)aniline. In a 250 mL roundbottom flask equipped with a stir bar, 0.5 g of 1-(3-nitrophenyl)-2-
phenyldiazene (2.2 mmol, 1 equiv) was added followed by 3.97 g of Na2S·9H2O (16.5 mmol, 7.5 equiv). The blend was dissolved in 54 mL
of dioxane, 14 mL of ethanol and 3.5 mL of water and set to reflux at 90 °C for 4 h. The product was purified by adding the solution to a
separatory funnel with 100 mL of ethyl acetate and 300 mL of water. The red organic phase was washed twice with 200 mL of water and
then once with 100 mL of brine. The organic phase was dried with MgSO4, filtered, and evaporated. The crude product was purified by silica column chromatography using a gradient of 0−50% ethyl acetate in hexanes. Red solid. Yield: 0.289 g, 67%.
1 H NMR (300 MHz, chloroform-d) δ, ppm: 7.87−8.02 (m, 2 H),
7.47−7.58 (m, 3 H), 7.41 (dt, J = 7.90, 1.17 Hz, 1 H), 7.33 (t, J = 7.75 Hz, 1 H), 7.20−7.28 (m, 1 H), 6.81 (ddd, J = 7.75, 2.34, 1.02 Hz, 1
H), 3.79 (br. s., 2 H).
13C NMR (300 MHz, chloroform-d) δ, ppm: 153.8, 152.7, 147.3, 130.9, 129.9, 129.1, 122.8, 117.9, 115.0, 107.4.
HR-MS (ESI, 4 kV) m/z: [M + H]+ calcd for C12H12N3, 198.1026;
found, 198.1023.
Еще:
J. Am. Chem. Soc. 2013 v135 #26 p9777-9784
Synthesis of 3,5-dichloro-4-[(2,6-dichloro-4-aminophenyl)diazenyl]aniline (16): To a solution of 15 (0.12 g, 0.31 mmol) in a mixture of dioxane/EtOH/H2O (8 mL:2 mL:0.5 mL) was added Na2S (0.073 g, 0.93 mmol) and the reaction mixture was heated at 90°C for 24h. Since
reaction did not complete as judged by TLC analysis, an additional Na2S (0.11 g, 1.41 mmol) was added and it was stirred at 90°C for further 5h. After cooling, the reaction was concentrated by rotary evaporation and extracted with ethyl acetate. The organic layer was washed with brine.
The combined organic layers were dried over Na2SO4, filtered and concentrated in vacuo. Purification by silica gel column chromatography gave 16 (0.046 g; 42 %) as a dark red solid.
1H NMR (400 MHz, CDCl3): δ ppm 6.52 (br, NH), 6.69 (s, 4H);
13C NMR (400 MHz, CDCl3): δ ppm 115.4, 128.4, 144.9, 149.7;
ESI-HRMS: m/z calc’d for C12H8Cl4N4: 348.95813 [M+H]+ ; found: 348.95840.
Physical Chemistry Chemical Physics (2016), 18, (22), 14795-14804
3-(Phenylazo)azobenzene: Nitrosobenzene (1.14 g, 10.4 mmol, 1.20 eq.) was added to a solution of 3-
nitroaniline (1.20 g, 8.63 mmol, 1.00 eq.) in 50 ml AcOH and was then stirred at rt overnight. The reaction
mixture was concentrated under reduced pressure and the residue was purified by column chromatography
(SiO2, cyclohexane/ethyl acetate 50:1) to obtain the 3- nitroazobenzene as an orange solid (1.60 g). It was used
without further purification for the next step. A solution of sodium hydrosulfide hydrate (1.09 g, 68%, 13.2
mmol) in 7 ml water was added to a solution of the crude 3-nitroazobenzene (1.00 g) in 35 ml ethanol. The
reaction mixture was stirred for 1 h at rt. Then, 60 ml water were added to precipitate yellow crystals. The
yellow solid was filtered off, washed with additional water and dried under vacuum to afford the crude 3-
aminoazobenzene (588 mg). It was used without further purification for the next step.
4-(Phenylazo)azobenzene: Nitrosobenzene (1.14 g, 10.4 mmol, 1.20 eq.) was added to a solution of 4-
nitroaniline (1.20 g, 8.63 mmol, 1.00 eq.) in 50 ml AcOH and was then stirred at rt for 3 days. The reaction
mixture was concentrated under reduced pressure and the residue was purified by column chromatography
(SiO2, cyclohexane/ethyl aceate 12:1) to obtain the 4- nitroazobenzene as a red solid (0.949 g). It was used
without further purification for the next step. A solution of sodium hydrosulfide hydrate (0.956 g, 68%,
11.6 mmol) in 6 ml water was added to a solution of the crude 4-nitroazobenzene (0.878 g) in 31 ml ethanol. The
reaction mixture was stirred for 3 h at rt. Then, 60 ml water were added to precipitate light orange crystals.
The solid was filtered off, washed with additional water and dried under vacuum to afford the crude 4-
aminoazobenzene (598 mg). It was used without further purification.
Synthesis of 3-(phenyldiazenyl)aniline. In a 250 mL roundbottom flask equipped with a stir bar, 0.5 g of 1-(3-nitrophenyl)-2-
phenyldiazene (2.2 mmol, 1 equiv) was added followed by 3.97 g of Na2S·9H2O (16.5 mmol, 7.5 equiv). The blend was dissolved in 54 mL
of dioxane, 14 mL of ethanol and 3.5 mL of water and set to reflux at 90 °C for 4 h. The product was purified by adding the solution to a
separatory funnel with 100 mL of ethyl acetate and 300 mL of water. The red organic phase was washed twice with 200 mL of water and
then once with 100 mL of brine. The organic phase was dried with MgSO4, filtered, and evaporated. The crude product was purified by silica column chromatography using a gradient of 0−50% ethyl acetate in hexanes. Red solid. Yield: 0.289 g, 67%.
1 H NMR (300 MHz, chloroform-d) δ, ppm: 7.87−8.02 (m, 2 H),
7.47−7.58 (m, 3 H), 7.41 (dt, J = 7.90, 1.17 Hz, 1 H), 7.33 (t, J = 7.75 Hz, 1 H), 7.20−7.28 (m, 1 H), 6.81 (ddd, J = 7.75, 2.34, 1.02 Hz, 1
H), 3.79 (br. s., 2 H).
13C NMR (300 MHz, chloroform-d) δ, ppm: 153.8, 152.7, 147.3, 130.9, 129.9, 129.1, 122.8, 117.9, 115.0, 107.4.
HR-MS (ESI, 4 kV) m/z: [M + H]+ calcd for C12H12N3, 198.1026;
found, 198.1023.
Еще:
J. Am. Chem. Soc. 2013 v135 #26 p9777-9784
Synthesis of 3,5-dichloro-4-[(2,6-dichloro-4-aminophenyl)diazenyl]aniline (16): To a solution of 15 (0.12 g, 0.31 mmol) in a mixture of dioxane/EtOH/H2O (8 mL:2 mL:0.5 mL) was added Na2S (0.073 g, 0.93 mmol) and the reaction mixture was heated at 90°C for 24h. Since
reaction did not complete as judged by TLC analysis, an additional Na2S (0.11 g, 1.41 mmol) was added and it was stirred at 90°C for further 5h. After cooling, the reaction was concentrated by rotary evaporation and extracted with ethyl acetate. The organic layer was washed with brine.
The combined organic layers were dried over Na2SO4, filtered and concentrated in vacuo. Purification by silica gel column chromatography gave 16 (0.046 g; 42 %) as a dark red solid.
1H NMR (400 MHz, CDCl3): δ ppm 6.52 (br, NH), 6.69 (s, 4H);
13C NMR (400 MHz, CDCl3): δ ppm 115.4, 128.4, 144.9, 149.7;
ESI-HRMS: m/z calc’d for C12H8Cl4N4: 348.95813 [M+H]+ ; found: 348.95840.
Physical Chemistry Chemical Physics (2016), 18, (22), 14795-14804
3-(Phenylazo)azobenzene: Nitrosobenzene (1.14 g, 10.4 mmol, 1.20 eq.) was added to a solution of 3-
nitroaniline (1.20 g, 8.63 mmol, 1.00 eq.) in 50 ml AcOH and was then stirred at rt overnight. The reaction
mixture was concentrated under reduced pressure and the residue was purified by column chromatography
(SiO2, cyclohexane/ethyl acetate 50:1) to obtain the 3- nitroazobenzene as an orange solid (1.60 g). It was used
without further purification for the next step. A solution of sodium hydrosulfide hydrate (1.09 g, 68%, 13.2
mmol) in 7 ml water was added to a solution of the crude 3-nitroazobenzene (1.00 g) in 35 ml ethanol. The
reaction mixture was stirred for 1 h at rt. Then, 60 ml water were added to precipitate yellow crystals. The
yellow solid was filtered off, washed with additional water and dried under vacuum to afford the crude 3-
aminoazobenzene (588 mg). It was used without further purification for the next step.
4-(Phenylazo)azobenzene: Nitrosobenzene (1.14 g, 10.4 mmol, 1.20 eq.) was added to a solution of 4-
nitroaniline (1.20 g, 8.63 mmol, 1.00 eq.) in 50 ml AcOH and was then stirred at rt for 3 days. The reaction
mixture was concentrated under reduced pressure and the residue was purified by column chromatography
(SiO2, cyclohexane/ethyl aceate 12:1) to obtain the 4- nitroazobenzene as a red solid (0.949 g). It was used
without further purification for the next step. A solution of sodium hydrosulfide hydrate (0.956 g, 68%,
11.6 mmol) in 6 ml water was added to a solution of the crude 4-nitroazobenzene (0.878 g) in 31 ml ethanol. The
reaction mixture was stirred for 3 h at rt. Then, 60 ml water were added to precipitate light orange crystals.
The solid was filtered off, washed with additional water and dried under vacuum to afford the crude 4-
aminoazobenzene (598 mg). It was used without further purification.
Re: Селективное восстановление нитроазоаренов
aber большое спасибо!!!
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