Nitric Acid → 2-Methyl-4-nitro-pyridin-1-ol

Participants

Reaction Conditions

Reaction Steps

2-Picoline-N-oxide (14)(21.9 g, 0.2 mmol) was added to a concentrated sulphuric acid (76 mL), maintaining the temperature below 40° C. The mixture was cooled to 5° C.; fuming nitric acid (60 mL) was the added dropwise over 15 minutes, maintaining reaction temperature below 10° C. After the addition was complete the reaction mixture was heated to 100° C. for 1.5 hours. The reaction was then cooled to rt and poured over ice (ca 500 g), the resultant green/yellow solution was neutralised by addition of sodium carbonate (ca 205 g over 1 hour). The mixture was then filtered and washed with water (2 L). The solid cake was then dissolved in DCM (500 mL) and dried over Na2SO4. Hexane (100 mL) was added to the DCM solution resulting in a yellow suspension which was filtered off and dried. Single peak in LC-MS analysis, (25.40 g 82.5%) no purification performed and taken through crude to next step.

Provenance & Evidence