Lawesson's reagent → (S)-2'-bromo-7'-iodospiro[morpholine-3,9'-xanthene]-5-thione
Reaction equation
[Br:1][C:2]1[CH:15]=[CH:14][C:13]2[O:12][C:11]3[C:6](=[CH:7][C:8]([I:16])=[CH:9][CH:10]=3)[C@:5]3([CH2:21][O:20][CH2:19][C:18](=O)[NH:17]3)[C:4]=2[CH:3]=1.COC1C=CC(P2(SP(C3C=CC(OC)=CC=3)(=S)S2)=[S:32])=CC=1>C1(C)C=CC=CC=1>[Br:1][C:2]1[CH:15]=[CH:14][C:13]2[O:12][C:11]3[C:6](=[CH:7][C:8]([I:16])=[CH:9][CH:10]=3)[C@:5]3([CH2:21][O:20][CH2:19][C:18](=[S:32])[NH:17]3)[C:4]=2[CH:3]=1Participants
4
Procedure
In a 250-mL flask, the (S)-2′-bromo-7′-iodospiro[morpholine-3,9′-xanthen]-5-one (1.483 g, 3.14 mmol) was suspended in toluene (30 mL). Lawesson's reagent (0.794 g, 1.963 mmol) was added. An air-cooled condenser was affixed, and the reaction vessel was placed in a 90° C. oil bath After 7 h, the reaction was concentrated. Without working it up, the residue was purified by chromatography (15% EtOAc/hexanes) to afford (S)-2′-bromo-7′-iodospiro[morpholine-3,9′-xanthene]-5-thione (1.25 g, 2.56 mmol).