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Synlett
Volumn , Issue 12, 2007, Pages 1897-1900
Baker-venkataraman rearrangement under microwave irradiation: A new strategy for the synthesis of 3-aroyl-5-hydroxyflavones
Author keywords

3 aroyl 5 hydroxyflavones; Antioxidant activity; Baker Venkataraman rearrangement; Microwave irradiation
Indexed keywords

2',4',6' TRIBENZOYLOXYACETOPHENONE DERIVATIVE; 2',6' DIAROYLOXYACETOPHENONE DERIVATIVE; 3 (3,4 DIHYDROXYBENZOYL) 3',4',5,7 TETRAHYDROXYFLAVONE; 3 AROYL 5 HYDROXYFLAVONE DERIVATIVE; 3',4' DIBENZYLOXY 3 (3,4 DIHYDROXYBENZOYL) 5 HYDROXYFLAVONE; 3',4' DIBENZYLOXY 5 HYDROXYFLAVONE; FLAVONE DERIVATIVE; PRIMULETIN; UNCLASSIFIED DRUG;
EID: 34547681720     PISSN: 09365214     EISSN: None     Source Type: Journal    
DOI: 10.1055/s-2007-984525     Document Type: Article
Times cited : (22)
References (24)
  • 13
    • 34547652051 scopus 로고    scopus 로고
    • Optimised Experimental Procedure A mixture of the 2′,6′-dihydroxyacetophenone (2a, 0.92 g, 6.05 mmol, the appropriate benzoic acid (13.31 mmol, 4-pyrrolidinopyridine (197 mg, 1.33 mmol, and N,N-dicyclohexylcarbodiimide (2.75 g, 13.33 mmol) in CH 2Cl2 (50 mL) was stirred at r.t. for 12 h. The obtained dicyclohexylurea was filtered off and washed with CH2Cl2 (2 x 25 mL, The filtrate was evaporated to dryness and the residue recrystallised in from EtOH to provide the 2′,6′- diaroyloxyacetophenones 3a-c (3a, 83, 3b, 78, 3c, 80, A mixture of the 2′,4′,6′-trihydroxyacetophenone (2b, 0.86 g, 5.11 mmol, the appropriate benzoic acid (16.88 mmol, 4-pyrrolidinopyridine (250 mg, 1.69 mmol, and N,N- dicyclohexylcarbodiimide (3.48 g, 16.87 mmol) in CH2Cl2 (100 mL) was stirred at r.t. for 20 h. The obtained dicyclohexylur
    • 2 (2 x 30 mL). The filtrate was evaporated to dryness and the residue recrystallised in from EtOH to provide the 2′,4′,6′-triaroyloxyacetophenones 4a-c (4a, 80%; 4b, 85%; 4c, 79%).
  • 14
    • 34547679342 scopus 로고    scopus 로고
    • Physical Data of 2′,4′,6′-Tribenzoyloxyacetophenone (4a) 1H NMR (300.13 MHz, CDCl3, δ, 2.51 (s, 3 H, 2-CH3, 7.25 (s, 2 H, H-3′,5′, 7.52 (dd, 6 H, J, 7.6, 6.4 Hz, H-3,5 of 2′,4′,6′-OCOC 6H5, 7.66 (t, 3 H, J, 7.6 Hz, H-4 of 2′,4′,6′-OCOC6H5, 8.15-8.20 (m, 6 H, H-2,6 of 2′,4′,6′-OCOC6H5) ppm. 13C NMR (75.47 MHz, CDCl3, δ, 31.4 (2-CH 3, 114.6 (C-3′,5′, 125.8 (C-1′, 128.4 (C-1 of 2′,6′-OCOC6H5, 128.6 (C-1 of 4′-OCOC6H5, 128.7 (C-3,5 of 4′-OCOC6H5, 128.8 (C-3,5 of 2′,6′-OCOC6H5, 130.25 (C-2,6 of 4′-OCOC6H5, 130.31 C-2,6 of 2′,6
    • +.
  • 15
    • 34547688687 scopus 로고    scopus 로고
    • Physical Data of 3′,4′-Dibenzyloxy-5-hydroxyflavone (5d) 1H NMR (300.13 MHz, CDCl3, δ, 5.25 and 5.26 (2 s, 2 x 2 H, 3′,4′-OCH2C6H 5, 6.57 (s, 1 H, H-3, 6.80 (dd, 1 H, J, 8.3, 0.7 Hz, H-6, 6.94 (dd, 1 H, J, 8.3, 0.7 Hz, H-8, 7.02 (d, 1 H, J, 8.5 Hz, H-5′, 7.31-744 (m, 6 H, H-3,4,5 of 3′,4′-OCH 2C6H5, 7.45 (br s, 1 H, H-2′, 745-7.51 (m, 5 H, H-6′ and H-2,6 of 3′,4′-OCH 2C6H5, 7.52 (t, 1 H, J, 8.3 Hz, H-7, 12.64 (s, 1 H, 5-OH) ppm. 13C NMR (75.47 MHz, CDCl 3, δ, 70.9 (3′-OCH2C 6H5, 71.5 (4′-OCH2C 6H5, 104.8 (C-3, 106.9 (C-8, 110.7 (C-10, 111.3 (C-6, 112. 8 (C-2′, 114.0 (C-5′, 120.7 C-6...
    • 5: 450.1467; found: 450.1472.
  • 21
    • 34547696700 scopus 로고    scopus 로고
    • Optimised Experimental Procedure A mixture of the appropriate 2′,6′-diaroyloxyacetophenone 3a-c and 4a-c (0.5 mmol) with anhyd K2CO3 (152 mg, 1.1 mmol) in anhyd pyridine (6 mL, was poured in a two-necked glassware apparatus equipped with a magnetic stirring bar, fibre-optic temperature control and reflux condenser, and was then irradiated in an Ethos SYNTH microwave (Milestone Inc, at constant power of 400 W for 10 min. After that period the reaction mixture was poured into a mixture of ice and water and the pH was adjusted to 3-4 with diluted HCl. The obtained solid was filtered off and recrystallised from EtOH to provide the 3-aroyl-5-hydroxyflavones 5a-c and 6a-c; in several cases a purification by column chromatography was necessary, using CHCl3 as eluent 5a, 70, 5b, 69, 5c, 72, 6a, 72, 6b, 68, 6c, 73
    • 3 as eluent (5a, 70%; 5b, 69%; 5c, 72%; 6a, 72%; 6b, 68%; 6c, 73%).
  • 22
    • 34547659568 scopus 로고    scopus 로고
    • Optimised Experimental Procedure BBr3 (1.5 mol per benzyloxy group) was added to a solution of the appropriate 3-aroyl-5- hydroxyflavone 5c and 6c (0.3 mmol) in anhyd CH2Cl 2 (25 mL) at low temperature, 70°C, After the addition was complete, the cooling system was removed and the reaction mixture was stirred at r.t. for 24 h. Then, H2O (50 mL) was added and the resulting reaction mixture was stirred at r.t. for 2-3 h. The obtained solid was filtered off and washed several times with H2O and CH2Cl 2; the expected 3-aroylflavones 7a,b were obtained in good yields (7a, 62, 7b, 58, Physical Data of 3-(3,4-Dihydroxybenzoyl)-3′,4′,5,7-tetrahydroxyflavone (7b) 1H NMR (300.13 MHz, DMSO-d6, δ, 6.25 (d, 1 H, J, 1.9 Hz, H-6, 6.48 (d, 1 H, J, 1.9 Hz, H-8, 6.73 d, 1 H, J, 8.4 Hz, H-5′
    • +.
  • 23
    • 34547653363 scopus 로고    scopus 로고
    • Physical Data of 3′,4′-Dibenzyloxy-3-(3,4- dibenzyloxybenzoyl)-5-hydroxyflavone(5c) 1H NMR (300.13 MHz, CDCl3, δ, 4.89 (s, 2 H, 3′-OCH2C 6H5, 5.16 (s, 2 H, 4′-OCH2C 6H5, 5.14 (s, 2 H, 3″-OCH2C 6H5, 5.21 (s, 2 H, 4″-OCH2C 6H5, 6.83 (dd, 1 H, J, 8.4, 0.7 Hz, H-6, 6.85 (d, 1 H, J, 8.6 Hz, H-5′, 6.88 (d, 1 H, J, 8.5 Hz, H-5″, 6.96 (dd, 1 H, J, 8.4, 0.7 Hz, H-8, 7.16 (d, 1 H, J, 2.2 Hz, H-2′, 7.22 (dd, 1 H, J, 8.6, 2.2 Hz, H-6′, 7.23-743 (m, 20 H, H-2,3,4,5,6 of 3′,4′,3″,4″-OCH 2C6H5, 7.47 (dd, 1 H, J, 8.5, 2.0 Hz, H-6″, 7.59 (t, 1 H, J, 8.4 Hz, H-7, 7.59 d, 1 H, J, 2.0 Hz, H-2″
    • +.
  • 24
    • 34547666364 scopus 로고    scopus 로고
    • The structural characterisation of 3-aroyl-5-hydroxyflavones 5a,b is according to the literature (ref. 7).
    • The structural characterisation of 3-aroyl-5-hydroxyflavones 5a,b is according to the literature (ref. 7).

* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.