* All experimental methods are cited from the reference, please refer to the original source for details. We do not guarantee the accuracy of the content in the reference.
General procedure: To a stirred solution of 7 (0.5mmol, 1 equiv) and α-diazo-β-ketosulfone 2 (143mg, 0.6mmol, 1.2 equiv) in dry EtOH (5mL) was added NaOEt (51mg, 0.75mmol, 1.5 equiv) at 0°C and the resulting mixture was stirred at the same temperature until the reaction was complete (monitored by TLC). Then the reaction mixture was concentrated in vacuo and the crude residue was directly subjected to silica gel column chromatography (pet ether/ethyl acetate: 8/2) to afford pure 3, 5 or 8.
Stage #1: With <i>L</i>-proline In dimethyl sulfoxide at 20℃; Stage #2: at 80℃;
General procedure: To a solution of L-proline (30 molpercent) in dry DMSO, substituted benzaldehyde (1 eq.) was added. The reaction mixture was stirred for 8-10 min at room temperature, and then ethyl acetoacetate (1.2 eq.) was added at the same temperature and reaction mixture was stirred at 80 °C for 6-8 h. After completion of the reaction, ethyl acetate was added (10 mL), the mixture was stirred for a few minutes, and quenched with cold water. The organic and aqueous layers were separated, and the aqueous layer was extracted with ethyl acetate (3 x 20 mL), washed with brine, and dried over anhydrous sodium sulfate. After removal of the solvent under reduced pressure, the crude product was purified by column chromatography on silica gel (60-120 mesh) using 5percent ethyl acetate in hexane.
84%
With piperidine; acetic acid In toluene at 20℃; for 19 h; Molecular sieve
Step 4: Synthesis of 2-benzylidene acetoacetate [Show Image]; Benzaldehyde (10.6 g,100 mmol), ethyl acetoactate (16.9 g, 130 mmol), acetic acid (1 ml) and piperidine (1.2 ml) were taken in dry toluene (20 ml) with Molecular sieve (4 g, 4 A) and stirred at room temperature for 19 h under LC-MS control, whereby the reaction went to completion. The reaction mixture was diluted with 20 ml cyclohexane, washed successively with water, 2M sodium hydroxide (aq), 1M hydrochloric acid (aq) and brine and then dried over magnesium sulfate. The solvent was then evaporated and the residue dried under high vacuum yielding a light yellow oil (18.3 g, 84percent).
Reference：
[1] Chemistry - A European Journal, 2017, vol. 23, # 21, p. 4962 - 4966
[2] Dalton Transactions, 2014, vol. 43, # 9, p. 3691 - 3697
[3] Journal of the Chemical Society, Perkin Transactions 1, 1980, p. 2645 - 2656
[4] Kinetics and Catalysis, 2011, vol. 52, # 4, p. 536 - 539
[5] Research on Chemical Intermediates, 2012, vol. 38, # 1, p. 25 - 35
[6] Tetrahedron Letters, 2018, vol. 59, # 24, p. 2347 - 2351
[7] European Journal of Organic Chemistry, 2006, # 16, p. 3767 - 3770
[8] Synthetic Communications, 2010, vol. 40, # 24, p. 3710 - 3715
[9] Patent: EP2266984, 2010, A1, . Location in patent: Page/Page column 22
[10] Organic Letters, 2014, vol. 16, # 15, p. 4048 - 4051
[11] Chemistry of Heterocyclic Compounds, 2005, vol. 41, # 3, p. 362 - 373
[12] Synthetic Communications, 2004, vol. 34, # 16, p. 2965 - 2971
[13] Synthetic Communications, 1996, vol. 26, # 16, p. 3025 - 3028
[14] Chemistry - A European Journal, 2012, vol. 18, # 28, p. 8659 - 8672
[15] Journal of the Chemical Society, Perkin Transactions 1: Organic and Bio-Organic Chemistry (1972-1999), 1989, p. 105 - 107
[16] Journal of the Chemical Society, Perkin Transactions 1: Organic and Bio-Organic Chemistry (1972-1999), 1989, p. 105 - 107
[17] New Journal of Chemistry, 2011, vol. 35, # 9, p. 1861 - 1866
[18] Catalysis Communications, 2010, vol. 11, # 7, p. 601 - 605
[19] European Journal of Organic Chemistry, 2013, # 28, p. 6379 - 6388
[20] Bulletin of the Chemical Society of Japan, 1989, vol. 62, # 12, p. 4072 - 4074
[21] Journal of Materials Chemistry A, 2014, vol. 2, # 45, p. 19360 - 19375
[22] Tetrahedron Letters, 1992, vol. 33, # 49, p. 7535 - 7538
[23] Chemistry of Materials, 2018, vol. 30, # 5, p. 1686 - 1694
[24] Green Chemistry, 2012, vol. 14, # 3, p. 840 - 846
[25] Justus Liebigs Annalen der Chemie, 1900, vol. 313, p. 167
[26] Chemische Berichte, 1896, vol. 29, p. 172[27] Chemische Berichte, 1898, vol. 31, p. 730,Anm. 4
[28] Justus Liebigs Annalen der Chemie, 1883, vol. 218, p. 175
[29] Justus Liebigs Annalen der Chemie, 1900, vol. 313, p. 167
[30] Justus Liebigs Annalen der Chemie, 1894, vol. 281, p. 63
[31] Tetrahedron Letters, 1988, vol. 29, # 18, p. 2261 - 2264
[32] Liebigs Annalen der Chemie, 1990, # 9, p. 841 - 846
[33] Tetrahedron Letters, 1988, vol. 29, # 49, p. 6437 - 6440
[34] Bulletin of the Academy of Sciences of the USSR, Division of Chemical Science (English Translation), 1985, vol. 34, # 2, p. 453[35] Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, 1985, # 2, p. 495 - 496
[36] Chemical and Pharmaceutical Bulletin, 1992, vol. 40, # 6, p. 1452 - 1461
[37] Indian Journal of Chemistry, Section B: Organic Chemistry Including Medicinal Chemistry, 1991, vol. 30, # 12, p. 1089 - 1094
[38] Angewandte Chemie - International Edition, 2004, vol. 43, # 5, p. 621 - 624
[39] Journal of Catalysis, 2007, vol. 246, # 1, p. 136 - 146
[40] Organic and Biomolecular Chemistry, 2004, vol. 2, # 8, p. 1213 - 1216
[41] Chemistry - A European Journal, 2010, vol. 16, # 4, p. 1221 - 1231
[42] Russian Journal of Organic Chemistry, 2010, vol. 46, # 4, p. 594 - 596
[43] Tetrahedron Letters, 2010, vol. 51, # 37, p. 4877 - 4881
[44] Patent: EP2266985, 2010, A1, . Location in patent: Page/Page column 20
[45] Chemical Communications, 2011, vol. 47, # 21, p. 6150 - 6152
[46] Tetrahedron Letters, 2011, vol. 52, # 28, p. 3605 - 3609
[47] Applied Catalysis A: General, 2011, vol. 398, # 1-2, p. 73 - 81
[48] Organic Letters, 2012, vol. 14, # 13, p. 3506 - 3509
[49] Journal of Medicinal Chemistry, 2012, vol. 55, # 13, p. 6149 - 6161
[50] Chemistry - A European Journal, 2012, vol. 18, # 40, p. 12773 - 12782
[51] Applied Catalysis A: General, 2012, vol. 445-446, p. 128 - 132
[52] Catalysis Science and Technology, 2013, vol. 3, # 2, p. 500 - 507
[53] Catalysis Letters, 2013, vol. 143, # 6, p. 563 - 571
[54] Catalysis Today, 2013, vol. 204, p. 140 - 147
[55] Chemical Science, 2014, vol. 5, # 2, p. 677 - 684
[56] Dalton Transactions, 2014, vol. 43, # 9, p. 3730 - 3738
[57] Australian Journal of Chemistry, 2013, vol. 66, # 8, p. 913 - 920
[58] Chemical Communications, 2014, vol. 50, # 64, p. 8900 - 8903
[59] RSC Advances, 2013, vol. 3, # 25, p. 9854 - 9864
[60] Chemical Science, 2014, vol. 5, # 11, p. 4517 - 4524
[61] Angewandte Chemie - International Edition, 2015, vol. 54, # 13, p. 4055 - 4059[62] Angew. Chem., 2015, vol. 127, # 13, p. 4127 - 4131,5
[63] Chemistry - A European Journal, 2014, vol. 20, # 40, p. 12808 - 12816
[64] Journal of Heterocyclic Chemistry, 2015, vol. 52, # 4, p. 1026 - 1031
[65] RSC Advances, 2016, vol. 6, # 103, p. 101171 - 101177
[66] Organic Letters, 2017, vol. 19, # 7, p. 1850 - 1853
[67] Tetrahedron Letters, 2017, vol. 58, # 8, p. 748 - 754
[68] Heterocycles, 2017, vol. 94, # 11, p. 2054 - 2064
[69] Advanced Synthesis and Catalysis, 2018, vol. 360, # 4, p. 808 - 813
[70] Inorganic Chemistry, 2018, vol. 57, # 4, p. 1774 - 1786
[71] Catalysis Letters, 2018, vol. 148, # 8, p. 2263 - 2273
[72] Research on Chemical Intermediates, 2018, vol. 44, # 9, p. 5635 - 5652
General procedure: To a stirred solution of 7 (0.5mmol, 1 equiv) and alpha-diazo-beta-ketosulfone 2 (143mg, 0.6mmol, 1.2 equiv) in dry EtOH (5mL) was added NaOEt (51mg, 0.75mmol, 1.5 equiv) at 0C and the resulting mixture was stirred at the same temperature until the reaction was complete (monitored by TLC). Then the reaction mixture was concentrated in vacuo and the crude residue was directly subjected to silica gel column chromatography (pet ether/ethyl acetate: 8/2) to afford pure 3, 5 or 8.
ethyl 7,8-dihydroxy-2-methyl-4-phenyl-4H-chromene-3-carboxylate[ No CAS ]
Yield
Reaction Conditions
Operation in experiment
75%
With trifluoroacetic acid In nitromethane at 120℃; for 5h;
2. General procedure for the synthesis of substituted benzopyran derivatives 5(a-u)
General procedure: To a stirred solution of substituted phenols (1 eq.) and substituted ethyl benzylidiene oxobutanoate derivatives (1.2 eq.) in nitromethane, TFA (1.0 eq.) was added drop wise at room temperature. The reaction mixture was refluxed at 120 °C for 4-7 hrs. After completion of reaction, excess nitromethane was removed from reaction under reduced pressure. Residue obtained was extracted with chloroform and water, organic layers were collected collected, washed with brine and dried over sodium sulfate. After removal of solvent under reduced pressure, crude product was purified by column chromatography on silica gel (230-400 mesh) using 20% ethyl acetate in hexane as eluent.
Chemistry
Pharmaceutical Intermediates
Inhibitors/Agonists
Material Science
For Research Only
110K+ Compounds
Competitive Price
1-2 Day Shipping
