HCID 14709354, compound → HCID 68578597, compound

Participants

Reaction Steps

A suspension of Thieno[3,2-c]isoquinoline 4-oxide (20 g, 99 mmol) in dry tetrahydrofuran (ca. 400 mL) was treated dropwise at −78° C. with an ethereal solution of ethylmagnesium bromide (3.0 M, 40 mL, 120 mmol) during 10 min. After 6 h the reaction mixture was quenched with 2 N aqueous hydrochloride acid (75 mL) and stirred for ca. 10 min. At this time the solution was treated with 2.5 N aqueous sodium hydroxide (65 mL). The resulting gelatinous residue was diluted with water (400 mL), filtered through Celite, and the filtrate was extracted with ethyl acetate (3×500 mL). The combined extracts were washed with water and brine (1.5 L each), dried (K3CO3) and concentrated in vacuo to give the crude product (19 g) as an orange oil which was taken up in methylene chloride (ca. 60 mL) and pre-adsorbed on silica gel (60 g). Flash chromatography on silica gel (740 g) eluting 2.5-, then 5-, and then 10% ethyl acetate-hexane provided the title compound (17 g, 81%, m.p. 39-41° C.) as a clear, pale yellow oil which crystallized on standing.

Provenance & Evidence