Ammonium Hydroxide → HCID 12677800, compound

Participants

Reaction Steps

A solution of 4-oxo-4H,5H-[1]benzothiopyrano[4,3-b]pyran-2-carboxylic acid (3.0 g, 11.53 mmoles, described in Example 79) in concentrated ammonium hydroxide (50 ml) is heated on a steam bath for 2.5 hr., and evaporated under reduced pressure. The residue is dissolved in water (75 ml) and added to a mixture of concentrated hyrochloric acid (5 ml) and ice. The precipitate is collected, washed with 0.07 N hydrochloric acid, acetone and ether to give the title compound as light yellow crystals, m.p. 256°-257° C.

Provenance & Evidence