关于硼氢化钠还原!? < align=left><B ><FONT face="Times New Roman">1,4-Cyclohexadione monoethylene ketal (<st1:chmetcnv w:st="on" TCSC="0" NumberType="1" Negative="False" HasSpace="True" SourceValue="5" UnitName="g">5.0 g</st1:chmetcnv>,32 mmol) was added to 100 mL of methanol in a 250 mL round bottom flask. The solution was cooled in an ice bath. NaBH4 (<st1:chmetcnv w:st="on" TCSC="0" NumberType="1" Negative="False" HasSpace="True" SourceValue="3.75" UnitName="g">3.75 g</st1:chmetcnv>, 97 mmol) was added portion-wise over 30 minutes. After3 minutes the ice bath was removed, and the mixture was stirred for an hour. The solvent was<o:p></o:p></FONT></B></P> < align=left><FONT face="Times New Roman"><B >then removed by rotatory evaporator and 35 mL of brine was added to the flask. The brine mixture was extracted with ethyl acetate (3</B><B >H</B><B >100 mL), the organic layer was dried with anhydrousMgSO4 and the solvent was removed by rotatory evaporator yielding the title compound as a colorless oil, (<st1:chmetcnv w:st="on" TCSC="0" NumberType="1" Negative="False" HasSpace="True" SourceValue="4.95" UnitName="g">4.95 g</st1:chmetcnv>, 98% yield). <o:p></o:p></B></FONT></P> < >我想问下<STRONG><FONT face="Times New Roman" size=5>NaBH4 (<st1:chmetcnv w:st="on" TCSC="0" NumberType="1" Negative="False" HasSpace="True" SourceValue="3.75" UnitName="g">3.75 g</st1:chmetcnv>, 97 mmol) was added portion-wise over 30 minutes。这部操作是如何实现的?是直接加硼氢化钠固体还是配成溶液滴加进去?如果是配成溶液那么是什么溶液? 甲醇 ?我发现甲醇和硼氢化钠会有气体产生,应该是发生反应,既然发生反应适合做溶剂吗?但是很多还原反应都是用甲醇做溶剂的,有哪位高手能指点一下?</FONT></STRONG></P>查看更多12个回答 . 5人已关注