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

Participants

Reaction Steps

To a stirring solution of 7-(5-phenoxy-3-pyridyl)-1,7-diazaspiro[4.4]nonane 30 (420 mg, 1.42 mmol) in 37% aqueous solution of formaldehyde (5 mL) was added 98% formic acid (3 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 thick brown viscous liquid. This was distilled using a Kugelrohr apparatus (2 mm, 180° C.) to give a very pale cream-colored syrup (400 mg, 90.9%).

Provenance & Evidence