There has been described the preparation of a series of dialkylaminoalkyl thiol esters derived from the benzoyl, cinnamoyl, 4-aminobenzoyl, 4 alkylaminobenzoyl, 4-alkoxybenzoyl and 2-butyloxyquinoline-4-carbonyl nuclei. Modifications in the preparation of certain intermediates, leading to increased yields, have also been described. From Kopsia fruticosa a new alkaloid, termed kopsine, C₂₂H₂₆N₂O₄, m. p. 217-218' (dec.), has been obtained. The isolation and properties of this alkaloid have been studied. On hydrolysis, it yields a base, kopsidine, C₂₀H₂₄N₂O₃, m. p. 142' ;and on hydrogenation, a dihydro derivative, m. p. 218' (dec.).