50% |
With sodium ethanolate; In ethanol; for 2h;Reflux; |
NaOEt (0.9 g, 13 mmol) was added to EtOH (10 mL) solution which include 3-hydroxy-3-methyl-2-butanone (9 g, 88 mmol) and malonitrile (12 g, 181 mmol) and then stirred for 1 h. After that,30 mL EtOH was added and the mixture was then refluxed for 1 h,which was then cooled in refrigerator. The solid precipitate was filtered and washed with minimal amount of cold EtOH, affording the compound 1 as off-white crystalline solid (8.8 g, 44 mmol, 50.0%). 1H NMR(400 MHz, DMSO-d6) delta (ppm): 2.37 (s, 3H), 1.60 (s, 6H). MS (ESI-TOF): calculated for C11H8N3O-, [M-H]-, m/z, 198.07, found: 198.42. |
48.4% |
With sodium ethanolate; In ethanol; at 20℃; for 12h;Inert atmosphere; |
Following literature reported procedure synthesis of fluorophore 1 and 2 was carried out in two steps starting from readily available compounds A and B.2 Briefly, 3-hydroxy-3-methyl-2-butanone (A, 9.0 g, 88 mmol) and malononitrile (B, 12.0 g, 181 mmol) were added to a stirred solution of sodium ethoxide in ethyl alcohol under nitrogen atmosphere. The resulting solution was stirred for 12 h at room temperature. Solvent was removed under high vacuum and the residue was purified by recrystallization from ethyl alcohol to give an off-white crystalline solid 2-(3-cyano-4,5,5-trimethylfuran-2(5H)-ylidene)malononitrile (C). Yield (8.5 g, 48.4%). |
44% |
With sodium ethanolate; In ethanol;Inert atmosphere; Reflux; |
Probe 1 was synthesized in two steps starting from readily available compound (4-formylphenyl)boronic acid.2 To a stirred solution of sodium ethoxide (0.9 g, 13 mmol) in dry ethanol 3-hydroxy-3-methyl-2-butanone (A, 9.0 g, 88 mmol) and malononitrile (B, 12.0 g, 181 mmol) were added under nitrogen atmosphere. The mixture was refluxed overnight under N2 atmosphere. Completion of the reaction was monitored by TLC. After completion of the reaction, excess solvent was removed under rotary evaporator. The residue was purified by recrystallization from ethanol to give an off-white crystalline solid 2-(3-cyano-4,5,5-trimethylfuran-2(5H)-ylidene)malononitrile (C). Yield (7.5 g, 44%). The product was dried under high vacuum and used in the next step. |
38% |
With sodium ethanolate; In ethanol; for 2h;Inert atmosphere; Reflux; |
Probe 1 was synthesized in two steps starting from readily available compound 3-(4-hydroxy-3,5-dimethoxyphenyl)acrylaldehyde.3,4 First, 3-hydroxy-3-methyl-2-butanone (A, 9.0 g, 88 mmol) and malononitrile (B, 12.0 g, 181 mmol) were added to a stirred solution of sodium ethoxide (0.9 g, 13 mmol) in ethanol under nitrogen atmosphere. The mixture was refluxed for 2 h under inert atmosphere. Excess solvent was removed under rotary evaporator. The residue was purified by recrystallization from ethyl alcohol to give an off-white crystalline solid 2-(3-cyano-4,5,5-trimethylfuran-2(5H)-ylidene)malononitrile (C). Yield (6.5 g, 38%). In the second step, 3-(4-hydroxy-3,5-dimethoxyphenyl)acrylaldehyde (D, 0.5 g, 2.42 mmol), 2-(3-cyano-4,5,5-trimethylfuran-2(5H)-ylidene)malononitrile (C, 0.531 g, 2.66 mmol) and ammonium acetate (0.205 g, 2.66 mmol) were dissolved in 20 mL dry THF/Ethanol (4:1; v/v) mixture under N2 atmosphere. The resulting solution was allowed to stir for 30 minutes at room temperature. After this time, 10 mL more solvent mixture was added and the solution was refluxed for 2 hours in dark condition under inert atmosphere. The mixture was allowed to cool at room temperature, and the excess solvent was evaporated under reduced pressure. The crude product was purified by silica gel column chromatography (40% hexane/ethyl acetate) to give the desired product (0.185 g, yield 20%). IR (cm-1, 3325, 2924, 2847, 2216, 2182, 1594, 1562, 1524, 1501, 1455, 1429, 1308, 1108). 1H NMR (400 MHz, DMSO-d6) delta 9.67 (s, 1H), 7.83 (d, 1H, J = 16 Hz), 7.33-7.22 (broad, 2H), 7.06-6.94 (t, 2H; J = 16 Hz), 6.68-6.64 (d, 1H, J = 15.2 Hz), 3.82 (s, 6H), 1.76 (s, 6H). 13C NMR (100.6 MHz, DMSO-d6) delta 177.9, 176.2, 149.7, 148.8, 142.0, 125.5, 113.5, 112.8, 112.7, 111.7, 108.5, 106.7, 99.5, 96.9, 56.8, 53.6, 25.9. Anal. calcd. for C22H19N3O4: C, 67.86; H, 4.92; N, 10.79. Found: C, 64.22; H, 5.35; N, 10.8. |
35% |
With sodium ethanolate; at 25℃; for 20h; |
A mixture of 1.50 g (0.065 mol)The metal sodium was dissolved in 190 mL of absolute ethanol,6.7 mL (0.064 mol) of compound 6 obtained in step 6) and 8.50 g (0.13 mol) of malononitrile were added;Stirred at room temperature for 20 hours,Steamed to remove ethanol,The residue was added with about 50 mL of water,With 6M hydrochloric acid to adjust the pH value of 4-5,Precipitate a large amount of tan oil;After sufficient washing with water,And then recrystallized twice with ethanol,After drying, 4.50 g of a pale yellow solid was obtained as compound 7,Yield: 35%. |
35% |
With sodium; In ethanol; at 20℃; for 20h; |
Dissolve 1.5 g (0.065 mol) of sodium metal in 190 ml of absolute ethanol,6.7 ml (0.064 mol) of compound 6 obtained in step S50 and 8.5 g (0.13 mol) of malononitrile were added,Then stirred at room temperature for 20 h,Ethanol was removed by rotary evaporation, the crude product obtained after the rotary evaporation was added with 50 ml of water,Then 6 mol / 1 hydrochloric acid solution to adjust the pH value of 4 ~ 5,A large amount of tan oil was precipitated; the oil was washed thoroughly with water and then recrystallized twice from ethanol,This gave 4.5 g of a pale yellow solid as compound 7 in 35% yield. |
35% |
With ethanol; sodium; at 20℃; for 20h; |
Dissolve 1.5 g (0.065 mol) sodium metal in 190 ml absolute ethanol and add 6.7 ml (0.064 mol) step 6) Obtained compound 6 and 8.5 g (0.13 mol) of malononitrile; stir at room temperature for 20 hours, rotovap to remove ethanol, add about 50 mL of water to the residue, adjust the pH to 4 to 5 with 6 M hydrochloric acid, and precipitate a large amount of tan oil. After washing well with water, it was recrystallized twice with ethanol and dried to give 4.5 g of pale yellow solid as compound 7 in a yield of 35%. |
35% |
With sodium; In ethanol; at 25℃; for 20h; |
1.5 g, 0.065 mol of sodium metal, was dissolved in 190 ml of absolute ethanol.6.7 ml, ie 0.064 mol, of compound 6 obtained in step 7) and 8.5 g, ie 0.13 mol of malononitrile, are added.Then stirred at room temperature for 20 h,The ethanol was removed by rotary evaporation, and 50 ml of water was added to the crude product obtained by rotary evaporation.Then, using a 6 mol/l hydrochloric acid solution to adjust the pH to 4 to 5, a large amount of brownish oil was precipitated;After thoroughly washing the oil with water, it was recrystallized twice with ethanol and then dried.4.5 g of a pale yellow solid was obtained as compound 8 in a yield of 35%. |
31.8% |
With magnesium ethylate; In ethanol; at 60℃; for 10h; |
A mixture of 3-hydroxy-3-methyl-2-butonone (5) (1.5 g, 14.7 mmol), malonontrile(6) (2.91 g, 44 mmol), magnesiumethoxide (2.02 g, 17.6 mmol) and absolute ethanol (20 mL) was stirred at 60 oCfor 10 h. Then the solvent was evaporated, and the residue was collected andwashed with 20 mL water. Then, the residue was recrystallized from ethanol togive product 7 as a yellow solid.Yield: 930 mg (31.8%). 1H NMR (CDCl3, 500 MHz): delta 2.37(s, 3H), 1.64 (s, 6H). |
|
With ethanol; sodium;Reflux; |
Acceptor 2-(3-cyano-4,5,5-trimethylfuran-2(5H)-ylidene)malononitrile (TCF) was synthesized according to a method published in the literature [13] with slight modification. In a 100 mL round-bottomed flask, a solution of sodium ethoxide was prepared by adding sodium (0.09g, 3.91mmol) to ethanol (60mL). To this solution 3- hydroxy-3-methyl-2-butanone (3.32mL, 30 mmol) and malononitrile (4.00g, 60 mmol) were added. The resulting mixture refluxed overnight. After concentration in vacuo, the residue was washed with diluted aqueous HCl. The crude precipitate was filtered and recrystallized from ethanol and gave the desired product, yield: 314g (95%, yellow solid). 2.37g (78%). C11H9N3O (199.209): calcd. C 66.32, H 4.55, N 21.09; found C 65.96, H 4.54, N 20.95.1H NMR (CDCl3, 400.1MHz, 20C): ||=1.63 (s, 6H), 2.36 (s, 3H), ppm. 13C NMR (CDCl3, 100.62MHz, 20C): ||=14.30, 24.49, 58.65, 99.84, 104.94, 109.06, 110.48, 111.12, 175.28, 182.61ppm. |
|
With pyridine; acetic acid; at 25℃; for 24h; |
Take 306 mg of 3-0H-3-CH3-2 butanone represented by Formula 7 in pyridine,Add 2-3 drops of acetic acid,Then 396 mg of malononitrile represented by Formula 8 was added,The molar ratio of 1: 2, in a 25 C oil bath for 24h,Then suction filtration,Get pure product 4 |
|
With sodium ethanolate; In ethanol; for 2h;Inert atmosphere; Reflux; |
(1) Using 10 ml of ethanol as the reaction solvent, carefully add 504 mg of sodium ethoxide to ethanol. Then, add 15 g of compound and 6.72 g of malononitrile in turn, with the molar ratio between 1:2 and 1:4, protected by nitrogen. Stirred 1h has reached a uniform purpose. Then, 30 ml of ethanol was added and the mixture was heated under reflux for 1 hour. After the reaction was completed, the reaction mixture was cooled. The pH of the reaction system was adjusted to 4-5 with 6M concentrated hydrochloric acid, and a large amount of solid was formed under cooling. The compound 2 was obtained by suction filtration and washing. The structure of compound 2 was characterized by NMR and ordinary mass spectrometry. |
|
With pyridine; acetic acid; at 25℃; for 24h; |
3-OH-3-CH3-2 butanone represented by formula 6 306 mg dissolved in pyridine, plus 2-3 drops of acetic acidFurther, 396 mg of malononitrile represented by Formula 7 was added, and the molar ratio of the two was 1:2, and the reaction was carried out in an oil bath at 25 C for 24 hours.Then suction filtration to obtain pure product 8 |
|
|
Add 5mmol, 1.00g 3-hydroxy-3-methylbutan-2-one to absolute ethanol, add 5mmol, 0.33g malononitrile, stir for 20 minutes under ice bath, add 5mmol, 0.34 g sodium ethoxide, moved to room temperature and stirred for 2 hours. After the reaction was completed, the solid was filtered and washed with anhydrous ethanol to obtain a gray-green solid; |