Reaktion #89796

Reaktionsgleichung

3-3

2-[(5-Chloro-1,3-benzoxazol-2-yl)amino]ethanol

methyl vinyl ketone

NaOH

Et3N

methanesulfonyl chloride

→

Methanesulfonic acid 2-[(5-chloro-benzooxazol-2-yl)-(3-oxo-butyl)-amino]ethyl ester

Lösungsmittel

DMF

Reaktionsbedingungen

Aufarbeitung

1. 1
   SonstigeTo a 1000 mL 3-neck round bottom flask equipped with a septum
2. 2
   workup.ADDITIONThe solution was diluted with 252 mL iPAc
3. 3
   Temperaturmaintaining internal temperature less than 10° C
4. 4
   workup.WAITAfter a further 30 minutes
5. 5
   WaschenThe solution was washed with 3×63 mL 5 w/w % aqueous NaHCO3 solution
6. 6
   workup.STIRRINGto stir overnight
7. 7
   Filtrationwas filtered
8. 8
   Waschenwashed with 2×50 mL 90:10 n-Heptane
9. 9
   SonstigeIPAc, and after drying with a nitrogen stream over the filter pad
10. 10
    Sonstige3-4 was obtained as a white crystalline solid (34.6 g., 96 mmol)

Vorschrift

To a 1000 mL 3-neck round bottom flask equipped with a septum, thermocouple, inert gas inlet and magnetic stir bar was charged 3-3 (25.2 g, 119 mmol). To this flask was added 126 mL DMF, 12.2 mL methyl vinyl ketone (148 mmol) and 0.119 mL 10M NaOH (1.19 mmol). The reaction was then aged for 6 hours, at which time conversion was judged to be complete by HPLC. The solution was diluted with 252 mL iPAc and cooled to 0° C., then 23.1 mL Et3N (166 mmol) followed by dropwise addition of 12.0 mL methanesulfonyl chloride (154 mmol) over 45 minutes, maintaining internal temperature less than 10° C. After a further 30 minutes, conversion was judged to be complete by HPLC. The solution was washed with 3×63 mL 5 w/w % aqueous NaHCO3 solution, then 66 mL water. After cutting the aqueous layer, the organics were reduced to approximately two volumes or 50 mL iPAc. The organics were then agitated by an overhead stirrer during slow addition of 151 mL n-Heptane over 4 hours. Over this time a crystalline white precipitate developed, and was allowed to stir overnight. At this time there was a thick slurry, which was filtered and washed with 2×50 mL 90:10 n-Heptane:IPAc, and after drying with a nitrogen stream over the filter pad, 3-4 was obtained as a white crystalline solid (34.6 g., 96 mmol). 1H NMR (500 MHz, CDCl3): δ=7.29 (s, 1H), 7.16 (d, J=8.2 Hz, 1H), 6.97 (d, J=7.8 Hz, 1H), 4.46 (s, 2H), 3.92 (s, 2H), 3.81 (t, J=5.9 Hz, 2H), 2.98-2.92 (m, 5H), 2.16 (s, 3H).

Quelle