Formaldehyde → 7-(5-Ethoxypyridin-3-yl)-1-methyl-1,7-diazaspiro[4.4]nonane

Participants

Reaction Steps

To a stirring solution of 7-(5-ethoxy-3-pyridyl)-1,7-diazaspiro[4.4]nonane (360.4 mg, 1.4 mmol) in 37% aqueous solution of formaldehyde (4 mL) was added 98% formic acid (2 mL) under nitrogen. The reaction mixture was heated to reflux for 8 h. The reaction mixture was cooled to room temperature, then basified with saturated aqueous sodium bicarbonate to pH 8-9 and extracted with chloroform (4×15 mL). The combined chloroform extracts were dried (Na2SO4), filtered and concentrated by rotary evaporation to afford a viscous brown liquid. This was distilled using a Kugelrohr apparatus (2 mm, 180° C.) to give a very light cream-colored syrup (340 mg, 89.3%).

Provenance & Evidence