Dimethylamine → Hydrochloric Acid

Participants

Reaction Conditions

Reaction Steps

A solution of 2-(dimethylamino)ethanol (32 mmol) in hexane (120 mL) was cooled to −5° C. and n-BuLi (64 mmol) was added. After 30 min 4-(dimethylamine=pyridine (16 mmol) was added and the red-orange mixture was stirred for further 1 h. The solution was cooled to −78° C. and 4-(trimethylsilyloxy)benzaldehyde (40 mmol) dissolved in hexane (80 mL) was added and the suspention was allowed to warm to rt over 20 min. The reaction mixture was quenched with water, and the aqueous phase was washed with CH2Cl2. The aqueous phase was evaporated to dryness, added NaI (96 mmol) and dissolved in MeCN (160 mL). Addition of trimethylsilylchloride (96 mmol) and stirring at rt for 16 h. The purple reaction mixture was evaporated to dryness and treated with an aqueous solution of Na2SO3 and pH was adjusted to 8. Extraction with CH2Cl2 gave after evaporation 560 mg (15%) slightly impure 4-(4-dimethylamino-pyridin-2-ylmethyl)phenol as yellow crystals. This was carbamoylated using general procedure 1 (CH2Cl2 was used as solvent) to give the title product as its hydrochloride after purification by preparative HPLC (Gilson) and treatment with HCl in Et2O (48%, ligt yellow crystals).

Provenance & Evidence