A Structural Puzzle

You have four C5H12O constitutional isomers, identified as A, B, C & D. All of these compounds react with sodium metal to liberate hydrogen gas. On treatment with hot phosphoric acid, each isomer is converted to one or more C5H10 isomers (E, F & G). Each of these three isomers (E, F & G) adds one equivalent of hydrogen (Pt catalyst), producing the same C5H12 compound H. Compounds A, B, C & D each behave differently on treatment with PCC (pyridinium chlorochromate) in methylene chloride. A gives a C5H10O aldehyde M, C gives an isomeric ketone K, D an isomeric aldehyde N, and B fails to react at all. These relationships are all outlined below.

A   +   H3PO4


B   +   H3PO4

E   +   F

C   +   H3PO4

F   +   G

D   +   H3PO4


A   +   PCC  
methylene chloride


B   +   PCC  
methylene chloride

No Change

C   +   PCC  
methylene chloride


D   +   PCC  
methylene chloride

E, F or G  +  H2 & Pt(catalyst)     H

After thinking about these facts and relationships, you should be able to assign structural formulas to all the unknown compounds designated by a bold letter above. To do so select an unknown from the following list and draw a formula using the drawing window on the left below. When you are finished,check your answer by pressing the Check Structure button. A help screen is available for the drawing window.

You have to enable Java and JavaScript on your machine !   Unknown A B C D E F G H K M N


This script written by William Reusch, Dept. of Chemistry, Michigan State University. Please send comments and corrections to whreusch@pilot.msu.edu.
JME Molecular Editor v2002.05 by: by Peter Ertl