Consider the structures of the four d-aldopentoses (See the following figure).

(a) Which d-aldopentose produces the same aldaric acid as d-lyxose?

(b) Which d-aldopentoses yield optically inactive alditols when treated with sodium borohydride?

(c) Which d-aldopentose yields the same alditol as l-xylose?

(d) Which d-aldopentose can close into a β-pyranose form in which all substituents are equatorial?

Transcribed Image Text:

Н. Н. Н. -Он -ОН -н -н Н Н Но Но -н -Он -ОН но -н Н -Он но Н. Н -ОН -ОН Н- Н. -ОН Н CH,OH D-Xylose CH-Oн D-Arabinose ČH,OH ČH,OH D-Ribose D-Lyхose