反应很简单,不知为什么我就做不出来,请高手指点!？ 该反应按文献:<br>1.Benzimidazole (1.57 g, 13.3 mmol) was placed in a two-necked flask. Tetrahydrofuran (40.0 mL) was added at 20 C to give a suspension. To this was added formaldehyde (1.0 mL, 1.0 equiv, 37% water solution), at 20 "C to give a homogeneous solution. After 5 min, TLC (silica gel and ethyl acetate) showed that benzimidazole was consumed and 1-(hydroxymethy1) benzimidazole was formed. The solvent was removed<br>under reduced pressure with a rotary evaporator, and the residue was dried in vacuo for 24 h.<br>2.<br>I-Hydroqmethyldiazotes (2) ; GeneraZ Procedme. The suitable diazole la-le (0.04 moll in 20 m l of<br>ethanol and 5 m l of 40%formalin was refluxed during 1 h with s t i r r i n g . The s t i r r i n g was continued<br>a t rmmtemperature f a r 12 h. The p r e c i p i t a t e ( i n t h e case of pyrazoles 2a and Zb it was necessary<br>t o add 40 ml of cold water) was f i l t e r e d off and purified by c r y s t a l l i z a t i o n from ethanol-water.<br>me y i e l d s in Table 1 are ones i s o l a t e d as pure compounds.<br><br>反复几次,点板都只有原料点!不反应啊!请高手指点一二! <br><br>查看更多15个回答 . 5人已关注
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