2-Methyltetrahydrofuran → Azd-1656

Participants

Reaction Conditions

Reaction Steps

To a flask was added 3-{[5-(azetidin-1-ylcarbonyl)pyrazin-2-yl]oxy}-5-[(1S)-2-methoxy-1-methylethoxy]benzoic acid (1.0 eq), 5-methylpyrazin-2-amine (1.0 eq) and 2-methyltetrahydrofuran (3.5 vols) under a nitrogen atmosphere. The mixture was cooled to 0° C. N-methylmorpholine (5.0 eq) was added at 0° C., then 1-propanephosphonic acid cyclic anhydride (T3P) (supplied as 50% w/w in ethyl acetate) (2.5 eq) was added in one portion via addition funnel over 45 minutes maintaining the reaction temperature at 0-5° C. The addition funnel was washed with 2-methyltetrahydrofuran (0.5 vols), then the reaction mixture was boiled under reflux under nitrogen for at least 14 hours, before being cooled to 22° C. Water (4.0 vols) was added to the reaction mixture in one portion, followed by 2-methyltetrahydrofuran (4.0 vols). After agitating for 30 minutes, the layers were separated. The upper organic layer was retained and the aqueous layer returned to the flask. 2-Methyltetrahydrofuran (4.0 vols) was added to the flask, the mixture was agitated for 30 minutes, then the layers were separated. The organic layers were combined in the flask and further 2-methyltetrahydrofuran (6.0 vols) was then added. The mixture was agitated, and 1.0N hydrochloric acid (4.0 vols) was then added. The mixture was agitated for at least 30 minutes at 22±5° C., and the layers were then separated. 1.0N Hydrochloric acid (4.0 vols) was added to the organic layer. The mixture was agitated for at least 30 minutes at 22±5° C. the mixture was separated 5% w/w Sodium hydrogen carbonate (4.0 vols) solution was added the organic layer. The mixture was agitated for at least 30 minutes at 22±5° C. then the mixture was separated. This process was repeated. Water (4.0 vols) was added to the organic layer, the mixture was agitated for at least 30 minutes at 22±5° C. then the layers were separated. The organic layer was distilled under vacuum at 35° C. collecting 19 vols of distillates. 2-Methyltetrahydrofuran (4 vols) was added, and the distillation was continued under vacuum at 35° C. collecting 6 vols distillates. Further 2-methyltetrahydrofuran (4 vols) was added and the reaction mixture sampled for water content. Further 2-methyltetrahydrofuran (4 vols) was added, and the reaction mixture was filtered through a CUNO™ filter then distilled until the pot volume was approximately 7 vols, then methyl iso-butylketone (11 vols) was added and the mixture vacuum distilled at 35° C. to a pot volume of approximately 7 vols. Methyl iso-butylketone (11 vols) was added and the mixture vacuum distilled at 35° C. to a pot volume of approximately 6 vols. N-Heptane (0.5 vols) was added to the mixture, and the temperature adjusted to 60° C., the mixture was cooled to 46° C., seeded, then cooled to 22° C. and agitated for at least 12 hours. The mixture was filtered. The solid was washed with a mixture of methyl iso-butylketone (1.5 vols)/heptane (0.16 vols). The solid was washed with heptane (˜1.5 vols). The isolated solid was dried at 22° C. under vacuum to afford the title compound as an off white solid. Corrected yield was 62%. 1H NMR δ (400 MHz DMSO) 11.04 (s, 1H), 9.26 (s, 1H), 8.68 (s, 1H), 8.57 (s, 1H), 8.36 (s, 1H), 7.57 (bs, 1H), 7.47 (bs, 1H), 7.13 (bs, 1H), 4.81-4.77 (m, 1H), 4.58-4.54 (t, 2H), 4.11-4.07 (t, 2H), 3.55-3.47 (m, 2H), 3.3 (s, 3H), 2.48 (s, 3H), 2.34-2.26 (m, 2H), 1.26-1.25 (d, 3H)

Provenance & Evidence