Hydrochloric Acid → HCID 73443586, compound

Participants

Reaction Conditions

Reaction Steps

To a suspension of isochromanone (99% pure, 149.7 g, 1.00 mol) in methanol (280 mL) was added dropwise over a period of 90 min at 14-16° C. sodium methanolate (30% in methanol, 270.0 g, 1.50 mol) and the resulting mixture was stirred for 90 min at 15° C. To this mixture was added dropwise over a period of 6.5 h at 9-13° C. iso-butyl nitrite (94% pure, 137.1 g, 1.25 mol) and the mixture was stirred at 8° C. overnight. The conversion was monitored by HPLC. After completion of the reaction, 4 M hydrochloric acid was added to adjust a pH<1 before the resulting suspension was stirred for overnight at 4° C. The crude product was collected by filtration, washed with cold dist. water (2×500 mL) and dried in vacuo at max. 45° C. Isochroman-3,4-dione-4-oxime was obtained as a colorless solid (145.9 g, 90.4 HPLC-area %, 74% yield).

Provenance & Evidence