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In conclusion, the ring bromination of kojic acid derivatives takes place at the 6 position, but the reaction occurs only when the 5-hydroxyl is free. Experimental SectionBromination of Chlorokojic Acid (2) with NBS. A mixture of 1.54 g of 2, 1.8 g of NBS, and 10 ml of CeHe was refluxed for 1 hr and was concentrated under vacuum.The residue was washed with water and recrystallized twice from absolute C2H5OH to yield 0.49 g of 3: mp 162-163°; positive Feds; ir (Nujol) 3150, 1580 cm-1.Bromination of Kojic Acid Monoacetate (9) with NBS. The same procedure was used with 0.197 g of 9, and yielded 0.217 g of 11 after recrystallization from CCI4, mp 131-133°, ir (Nujol) 3350, 1740, 1640 cm-1.

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