Solution Found!
Identify the sugar in each description.a. An aldopentose
Chapter 21, Problem 33P(choose chapter or problem)
Problem 33P
Identify the sugar in each description.
a. An aldopentose that is not D-arabinose forms D-arabinitol when it is reduced with NaBH4.
b. A sugar that is not D-altrose forms D-altraric acid when it is oxidized with nitric acid.
c. A ketose that, when reduced with NaBH4, forms D-altritol and D-allitol.
Questions & Answers
QUESTION:
Problem 33P
Identify the sugar in each description.
a. An aldopentose that is not D-arabinose forms D-arabinitol when it is reduced with NaBH4.
b. A sugar that is not D-altrose forms D-altraric acid when it is oxidized with nitric acid.
c. A ketose that, when reduced with NaBH4, forms D-altritol and D-allitol.
ANSWER:
Solution 33P
(a)
When D-arabinose is treated with NaBH4 followed by workup using dilute acid the aldehyde group is reduced into primary alcohol.
Now, another aldopentose which is not D-arabinose gives the same reduced product. Hence the probable structure of that compound could be that of opposite of arabinose i.e. the terminal CHO and CH2OH groups interchanged.