Interconversão de Aldoses e Cetoses

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468 Chapter 24 CARBOHYDRATES: POLYFUNCTIONAL COMPOUNDS IN NATURE So a basic solution of either one rapidly becomes a mixture of the two, and the reactions in (a) can then occur. This aldose ketose interconversion is general. Glucose and fructose are interconverted by aqueous base. for example. We saw this same mechanism in Problem 41. 61. (a) Br₂, H₂O; (b) see answer to Problem 43b; (c) CH₃OH, (d) ester of acid in (b): at the top: (e) forms the amide: -CONH₂ at the top. Then CONH₂ NH₂ CHO H OH H OH H Br₂. NaOH 1 H CO₂ + HO H H OH Hofmann -NH₃ H OH degradation H OH CH₂OH CH₂OH CH₂OH D-Threose (e) (f) (g) The hydroxyamine (f) readily loses on the heating to give the aldehyde. This sequence achieves the removal of from an aldose to form a new aldose with one less carbon, just like the Wohl and Ruff degradations. 62. (a) (b) H (c) H H OH H OH HO H HO H O H OH H OH H H CH₂OH COOH (d) CHO (e) CH₂OH (f) CH₂OH H OH H OH H OH HO H HO H H H OH H OH H OH H OH H OH H OH COOH COOH C (g) CH₂OH CHO H OH H H HO H Rotate H OH H OH H OH HO H CHO CH₂OH