Textbook QuestionPredict the products obtained when d-galactose reacts with each reagent. (b) NaOH, H2O303views
Textbook QuestionExcept for the Tollens test, basic aqueous conditions are generally avoided with sugars because they lead to fast isomerizations. (a) Under basic conditions, the proton alpha to the aldehyde (or ketone) carbonyl group is reversibly removed, and the resulting enolate ion is no longer asymmetric. Reprotonation can occur on either face of the enolate, giving either the original structure or its epimer. Because a mixture of epimers results, this process is called epimerization. Propose a mechanism for the base-catalyzed equilibration of glucose to a mixture of glucose and its C2 epimer, mannose.294views
Textbook QuestionUse Figure 23-3 <IMAGE> (the D family of aldoses) to name the following aldoses.(a) the C2 epimer of D-arabinose(b) the C3 epimer of D-mannose(c) the C3 epimer of D-threose249views
Textbook QuestionWhich of the following molecule pairs are epimers?(a) <IMAGE>(b) <IMAGE>(c) <IMAGE>201views
Textbook QuestionWhen glucose undergoes base-catalyzed isomerization in the absence of the enzyme, mannose is oneof the products that is formed (Section 20.5). Why is mannose not formed in the enzyme-catalyzed reaction?207views
Textbook Question(a) Draw D-allose, the C3 epimer of glucose. (b) Draw D-talose, the C2 epimer of d-galactose1400views1rank
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