Because both C-1 and C-6 are oxidized to CO2H groups by nitric acid, Fischer recognized

Chapter 23, Problem 23.48

(choose chapter or problem)

Because both C-1 and C-6 are oxidized to CO2H groups by nitric acid, Fischer recognized that two diastereomeric hexoses could give the same aldaric acid. 6CH2OH CHOH CHOH CHOH CHOH CH O 1 6 CH2OH CHOH CHOH CHOH CHOH CH O CO2H CHOH CHOH CHOH CHOH CO2H or HNO3 Of the (+)-glucose/(+)-mannose pair (pair 3 in 23.46), only (+)-glucose has a diastereomeric hexose that gives the same aldaric acid. Fischer synthesized that specific diastereomer and found it gave the same aldaric acid as (+)-glucose. Thus, he was able to determine that (+)-glucose and (+)-mannose are: ()-Glucose ()-Mannose CH O H OH HO H OH H H OH CH2OH CH O HO HO H H OH H H OH CH2OH Which hexose did Fischer synthesize that gave the same aldaric acid as (+)-glucose? A. B. CH O HO OH OH H H H H OH CH2OH CH O H HO H HO H OH H CH2OH HO C. D. CH O HO HO OH H H OH H H CH2OH CH O H OH HO HO H H H CH2OH H