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Volumn , Issue 2, 2007, Pages 313-317

Lawesson's reagent and microwaves: A new efficient access to benzoxazoles and benzothiazoles from carboxylic acids under solvent-free conditions

Author keywords

Benzothiazoles; Benzoxazoles; Lawesson's reagent; Microwaves; Thiobenzoic acid

Indexed keywords

2 PHENYLBENZOTHIAZOLE; 2 PHENYLBENZOXAZOLE; 2,4 BIS(4 METHOXYPHENYL) 1,3,2,4 DITHIADIPHOSPHETANE 2,4 DISULFIDE; BENZOIC ACID DERIVATIVE; BENZOTHIAZOLE DERIVATIVE; BENZOXAZOLE DERIVATIVE; CARBOXYLIC ACID; DISULFIDE; THIOBENZOIC ACID; UNCLASSIFIED DRUG;

EID: 33847036694     PISSN: 09365214     EISSN: None     Source Type: Journal    
DOI: 10.1055/s-2007-967994     Document Type: Article
Times cited : (114)

References (64)
  • 17
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    • Loupy, A, Ed, Wiley-VCH: Weinheim
    • (a) Microwaves in Organic Synthesis; Loupy, A., Ed.; Wiley-VCH: Weinheim, 2002.
    • (2002) Microwaves in Organic Synthesis
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    • Chem. Abstr. 2004, 141, 295952.
    • Chem. Abstr. 2004, 141, 295952.
  • 42
    • 33847060405 scopus 로고    scopus 로고
    • Lawesson reagent is used as purchased from Fluka (98% purity). Reactions must be carried out in an efficient fume hood.
    • Lawesson reagent is used as purchased from Fluka (98% purity). Reactions must be carried out in an efficient fume hood.
  • 43
    • 33847050571 scopus 로고    scopus 로고
    • General Procedure for the Synthesis of Benzoxazoles 4 or Benzothiazoles 5, Synthesis of 3-Methylbenzoxazole (4f, A mixture of 3-methylbenzoic acid (6f, 136 mg, 1 mmol, 2-aminophenol (109 mg, 1 mmol) and Lawesson's reagent (141 mg, 0.35 mmol) was irradiated in an open vessel with microwaves in a monomode oven (Discover CEM, 300W and temperature control set at 190°C measured with an IR sensor) for 4 min. The crude was dissolved in CH2Cl2 (30 mL) and washed with 10% aq NaOH (2 x 20 mL, dried (Na2SO4) and evaporated to give pure (as per NMR) 2-(3-methylphenyl)benzoxazole (4f, further purification by flash chromatography gave 188 mg (90, as a white solid. Mp 82-83°C (EtOH, lit.44 81-82°C. 1H NMR (300 MHz, CDCl3, δ, 8.09 (s, 1 H, ArH, 8.05 (d, 1 H, ArH, J, 7.6 Hz, 7.79-7.76 (m, 1 H, ArH, 7.58-7.55 (m, 1 H, ArH, 7.40 t, 1 H, ArH, J, 7.6 Hz, 7.35-7
    • +], 180 (7).
  • 54
    • 33847074137 scopus 로고    scopus 로고
    • Data of Previously Undescribed Compounds. 2-(2,3-Dimethoxyphenyl) benzoxazole (4c, mp 75-76°C (hexane, 1H NMR (300 MHz, CDCl3, δ, 7.83-7.77 (m, 1 H, ArH, 7.69 (dd, 1 H, ArH, J, 7.9, 1.5 Hz, 7.60-7.53 (m, 1 H, ArH, 7.35-7.29 (m, 2 H, ArH, 7.14 (t, 1 H, ArH, J, 8.0 Hz, 7.03 (dd, 1 H, ArH, J, 8.2, 1.4 Hz, 3.99 (s, 3 H, OCH3, 3.87 (s, 3 H, OCH3, 13C NMR (75 MHz, CDCl3, δ, 161.7, 154.0, 150.9, 149.0, 142.2, 125.3, 124.6, 124.5, 122.6, 122.0, 120.4, 115.6, 110.8, 61.7, 56.3. MS (EI, m/z, 255 (100, M, 240 (18, 226 (56, 212 (10, 197 (13, 169 (2, Anal. Calcd for C15H13NO3: C, 70.58; H, 5.13; N, 5.49. Found: C, 70.41; H, 5.09; N, 5.38. 2-(2,4,5- Trimethoxyphenyl)benzoxazole (4e, mp 146-148 °C (hexane, 1H NMR (300 MHz, CDCl3, δ, 7.72-7.69 m, 1 H, ArH, 7.59
    • 2S: C, 67.34; H, 5.30; N, 4.91. Found: C, 67.14; H, 5.28; N, 4.85.
  • 57
    • 28044434233 scopus 로고    scopus 로고
    • Schaumann, E, Ed, Thieme: Stuttgart
    • Ulrich, H. In Science of Synthesis, Vol. 11; Schaumann, E., Ed.; Thieme: Stuttgart, 2001, 835-912.
    • (2001) Science of Synthesis , vol.11 , pp. 835-912
    • Ulrich, H.1


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.