Acetic Acid → 2-Methylpyridine-4-carboxylic acid

Temperature

17.5 °C

1.63 g Dimethyl-[2-(2-methyl-pyridin-4-yl)-vinyl]-amine (10 mmol) were dissolved in 19 ml acetic acid containing 1 ml H2O. To the red solution maintained and stirred at ca. 15-20° C. was passed O3 (˜85 mmol/hour) for 1 hour. The reaction was mildly exothermic, changing in appearance from an orange (10 min) to a yellow solution (15 min) then from a yellow (20 min) to a white suspension (30 min). Excess ozone was purged with argon until a peroxide test was essentially negative. 1.02 ml 30% aqueous H2O2 (10 mmol) was added in one portion, and the resulting yellow suspension was stirred at 50° C. for 2 hours during which time a white suspension was formed. With the aid of toluene, the aqueous acetic acid solvent was removed under reduced pressure (45° C./100-50 mbar). The white residue was briefly digested in 25 ml tert. butyl methyl ether (TBME) at 40° C. then at ambient temperature for 30 min. The product was filtered, washed with TBME and dried for 2 hours at 45° C./25 mbar: 1.17 g (85%) biege crystals (GLC 98 area %, as trimethylsilylester).

1. temperatureTo the red solution maintained
2. customfor 1 hour
3. customchanging in appearance from an orange (10 min) to a yellow solution (15 min)
4. customfrom a yellow (20 min)
5. customto a white suspension (30 min)
6. customExcess ozone was purged with argon until a peroxide test
7. stirringthe resulting yellow suspension was stirred at 50° C. for 2 hours during which time a white suspension
8. customwas formed
9. customWith the aid of toluene, the aqueous acetic acid solvent was removed under reduced pressure (45° C./100-50 mbar)
10. customwas briefly digested in 25 ml tert. butyl methyl ether (TBME) at 40° C.
11. filtrationThe product was filtered
12. washwashed with TBME
13. customdried for 2 hours at 45° C./25 mbar

ORD record

ord-2f4b46577e2c4d9b952d21f191ec937e

Source dataset

uspto-grants-2008_12

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07459563B2