N-HYDROXY-2,4-DIMETHOXY-BENZAMIDINE synthesis

Yield:-

Reaction Conditions:

Stage #1: 2,4-dimethoxybenzonitrilewith hydroxylamine hydrochloride;potassium carbonate in ethanol at 85; for 27 h;
Stage #2: with hydrogenchloride in ethanol;water;Acidic conditions;
Stage #3: with sodium hydroxide in water;Alkaline aqueous solution;

Steps:

1.a

a) A mixture of 2,4-dimethoxybenzonitrile (3.25 g, 20 mmol), hydroxylamine hydrochloride (2.92 g, 42 mmol) and K₂CO₃ (5.80 g, 42 mmol) in ethanol (80 mL) is stirred at 85° C. for 27 h before it is poured onto water (250 mL). The solution is acidified by adding 1 N aq. HCl (75 mL) and extracted once with DCM (100 mL). The aq. layer is basified with 1 N aq. NaOH (90 mL) and extracted three times with DCM (3*150 mL). The organic extracts are dried over MgSO₄, the solvent is evaporated and the residue is dried under high vacuum to leave N-hydroxy-2,4-dimethoxy-benzamidine (1.35 g) as a beige solid. LC-MS: t_R=0.68 min, [M+1]⁺=197.11.

References:

US2008/318955,2008,A1 Location in patent:Page/Page column 12