Synthesis of 2H-3,1-pyrazolo[3,4-e]oxazines via a new conversion of Friedländer reaction

Chinese Chemical Letters

Volumn 18, Issue 6, 2007, Pages 636-638

  Li, Jia Rong ^a   Zhang, Li Jun ^a   Chen, Jin Nan ^a   Yang, Xi Quan ^a   Wang, Li Jun ^a   Zhao, Xiao Fan ^a   Qiu, Jun Xia ^a  

^a BEIJING INSTITUTE OF TECHNOLOGY   (China)

Author keywords

Cyclocondensation; Oxazines; Pyrazole; Synthesis; Tacrine

Indexed keywords

EID: 34249806695     PISSN: 10018417     EISSN: None     Source Type: Journal    
DOI: 10.1016/j.cclet.2007.04.015     Document Type: Article

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18. 2 (1.2 mmol, 0.16 g) for 5 h (monitored by TLC). The reaction mixture was cooled and dispersed into water and titrated to pH 12-13 by 20% sodium hydroxide. After filtration, the filtrate was extracted three times with ethyl acetate, the organic layers were dried and evaporated at reduced pressure to give the solid product. The product was purified by silica gel column chromatography eluting with ethyl acetate/light petroleum (2:1/v:v) to give 5b and 6b, respectively.
19. 4: C, 72.70; H, 6.10; N, 21.20. Found: C, 72.41; H, 6.08; N, 20.27.