lea (Stranger)
08-28-04 14:16
No 527944
      2,5-dmba to 2,5-dmns scaleup question     

Hey all, I finally found a interesting route to the nitrostyrene on rhodiums site. The procedure looks accurate enough, but sadly that ratios they are using are to small, in theory the ratio or mmol can up scaled up right? I was thinking about it and it would be possible but that factors will change, heat length et cetera et cetera? Can any one give me some insight on the possibilities of scaling the procedure up.

2,5-dimethoxybenzaldehyde (1.97 g, 11.8 mmol) and nitromethane (0.72 g, 11.8 mmol) in methanol (200 mL) was stirred at room temperature until the solids dissolved. The solution was cooled to 0 deg C and a 10.5 M NaOH solution (2 mL) was added dropwise over 20 min. The alkaline solution was
added slowly to a 4% HCl solution (200 mL) maintained at 60 deg C. The pale yellow amorphous solid that formed was filtered and washed with water (200 mL). The crude product was recrystallized from absolute ethanol to give yellow
needles (2.11 g, 85%)

Preparation of 10.5 M NaOH: Dissolve 10.5g sodium hydroxide under cooling in 20ml water, and after cooling dilute the solution to exactly 25ml.
 
 
 
 
    Natrix
(Hive Bee)
08-28-04 22:17
No 527988
      Is this better?     

http://www.orgsyn.org/orgsyn/prep.asp?prep=cv1p0413