Iodine → (E)-(1R,6S,7R,10S,21S)-21-benzyl-6-hydroxy-7-isopropyl-2,3-dioxa-12,13-dithia-8,18,23-triaza-bicyclo[8.7.6]tricos-16-ene-4,9,19,22-tetraone

Participants

Reaction Steps

To a solution of iodine (198.4 mg, 0.78 mmol) in CH2Cl2/MeOH (9:1, 272 mL) was added dropwise a solution of 6A (79.4 mg, 0.08 mmol) in CH2Cl2/MeOH (9:1) (134 mL) over 30 min, the reaction mixture was then allowed to stir for a further 30 min after which time sodium thiosulfate (88 mL, 0.05 M) was added. The layers were separated and the product was extracted with CH2Cl2 (3×45 ml) dried (MgSO4) and the solvent was removed in vacuo. Purification was then carried out by column chromatography on silica gel (eluent 3:97 MeOH/CH2Cl2) which gave 7A (30 mg, mmol, 68%) as a white solid: Rf 0.19 CH2Cl2/MeOH (97:3); [α]26D=−83.7 (c 0.38, MeOH).

Provenance & Evidence