Acetic Acid → HCID 15282632, compound

Temperature

90 °C

3-Hydroxy-pyridine (23.8 g, 0.25 mol) and solid sodium hydroxide (NaOH, 10.0 g, 0.25 mol) are dissolved in water (100 mL) and the solution is heated to 90° C. To this hot stirred solution, a 37% aqueous solution of formaldehyde (85 mL) is added dropwise over a period of eight (8) hours. After the addition of formaldehyde is completed, the mixture is stirred at 90° C. for an additional 90 minutes. Heating is then discontinued and the mixture is chilled at 0° C., neutralized by the addition of 15 mL of acetic acid (CH3COOH), and evaporated to dryness in a rotary evaporator under reduced pressure. The residue is taken up in 200 mL of dimethylformamide, filtered to remove any undissolved solid which is discarded, and acidified by the addition of concentrated aqueous hydrochloric acid (25 mL). The acidified solution is evaporated to dryness in a rotary evaporator under reduced pressure and the residue is dissolved in methanol (150 mL), clarified with activated charcoal, and filtered. The resulting clear solution is again evaporated to dryness in a rotary evaporator under reduced pressure. Recrystallization of the oily residue, first from n-propanol and then from methanol-acetone, yields the desired product (yields, 35%) as a cream-colored solid, m.p. 144° C., having the correct analytical and spectral (IR and NMR) properties.

1. temperatureHeating
2. temperaturethe mixture is chilled at 0° C.
3. customevaporated to dryness in a rotary evaporator under reduced pressure
4. filtrationfiltered
5. customto remove any undissolved solid which
6. additionacidified by the addition of concentrated aqueous hydrochloric acid (25 mL)
7. customThe acidified solution is evaporated to dryness in a rotary evaporator under reduced pressure
8. dissolutionthe residue is dissolved in methanol (150 mL)
9. filtrationfiltered
10. customThe resulting clear solution is again evaporated to dryness in a rotary evaporator under reduced pressure
11. customRecrystallization of the oily residue

ORD record

ord-38dab094876542b6abdd17d299bbb41c

Source dataset

uspto-grants-1997_12

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05696240