反应条件: temp:50.01; pressure:0.00; stir:; See reaction.notes.procedure_details.
实验步骤: 380 ml (373 grams, 4.97 moles) of 3-amino-1-propanol and 450 ml of tetrahydrofuran ("THF") were added to a 5-L flask fitted with a mechanical stirrer, teflon clad thermol-couple and an addition funnel. Then with rapid stirring, 749 grams (4.59 moles) of the 2,6-dimethylphenylisothiocyanate were added dropwise over a 2 hour period. The temperature was kept below 45° C. by controlling the rate of addition and by the use of a cooling bath. The cooling bath was removed, and replaced with a heating mantle. The temperature was raised to 50° C. followed by the addition of 435 ml. concentrated hydrochloric acid. The addition funnel was removed and a distillation head was placed on the flask. Heating was continued with the distillation of THF and water until the internal temperature had reached 95° C., which took about 2 hours. The reaction mixture was then diluted with 2 liters of water and the stirred solution was allowed to cool to room temperature. The aqueous solution was filtered through a 0.2 microfilter. The reaction mixture was made basic by the careful addition of 10% sodium hydroxide. The addition was continued until the pH of the solution was greater than or equal to 12. A solid was collected by filtration, washed with water and partially dryed in the funnel. The solid was then transferred into a flask fitted with a mechanical stirrer and 1 liter of acetone was added. The slurry was stirred for 1 hour using an ice bath to chill the mixture. The product was isolated by filtration, and air dryed to give 750 grams of crude xylazine. The product had a purity of 99% by GC analysis and gave a IR spectrum that was virtually identical to that of a standard sample of xylazine. The 80 MHz 1HNMR spectrum (CDCl3) produced the following results: delta 7.15 (bs, 3, ArH), 4.5 (t, 2, CH2), 3.15 (t, 2, CH2), 2.9-2.0 (m, 8, CH2 and CH3) was in complete agreement with a spectrum of a standard xylazine sample. Furthermore, the mixed melting point of the xylazine sample and a standard showed no depression.
fitted with a mechanical stirrer
was kept below 45° C.
the rate of addition
The cooling bath was removed
followed by the addition of 435 ml
The addition funnel was removed
Heating
was continued with the distillation of THF and water until the internal temperature
had reached 95° C.
The reaction mixture was then diluted with 2 liters of water
to cool to room temperature
The aqueous solution was filtered through a 0.2 microfilter
The reaction mixture was made basic by the careful addition of 10% sodium hydroxide
The addition
A solid was collected by filtration
washed with water
The solid was then transferred into a flask
fitted with a mechanical stirrer
1 liter of acetone was added
to chill the mixture
The product was isolated by filtration, and air
来源 ID: ord-8fc192c1eb7a4266a40f904b2439f6a4