Hydrochloric Acid → 2-Chloro-6-(hydroxymethyl)-3-pyridinol

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

2-Chloro-3-pyridinol (20.0 g, 0.154 mole and NaHCO3 (19.5g, 0.232 mole, 1.5 equ) are dissolved in 150 ml of water. The reaction mixture is placed in an oil bath at 90° C. and after 5 min is treated with 37% aqueous formaldehyde (40.5 ml, 0.541 mole, 3.5 equ) which is added in six unequal doses; 12 ml initially, 3×8 ml followed by 1×2.2 ml all at 90 min intervals with the final 2.3 ml added after maintaining at 90° C. overnight (15 h). After stirring in the 90° C. bath for an additional 4 h, the flask is placed in ice bath, and the contents are treated with 100 ml of crushed ice, acidified with 39 ml of 6 N HCl to pH 1, and the precipitated material is stirred for 1.5 h in an ice bath. The undesired solid is removed by filtration, and the filtrate is extracted seven times with EtOAc. The combined organic extracts are concentrated at reduced pressure, treated with toluene, reconcentrated on rotary evaporator to azeotrope most of the water, suspended in CH2Cl2 and reconcentrated again at reduced pressure to obtain 19.9 g (81%) of 2-chloro-6-(hydroxymethyl)-3-pyridinol as a pale yellow solid sufficiently pure for subsequent reaction. MS for C6H6ClNO2: m/z: 159 (M)+.

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