Log out Go to App
Go to App

Learning Materials

Features

Discover

Chapter 20: Q57P (page 1038)

An unknown compound shows a weak molecular ion at m/z 87 in the mass spectrum, and the only large peak is at m/z 30. The IR spectrum follows. The NMR spectrum shows only three singlets: one of area 9 at δ 0.9, one of area 2 at δ 1.0, and one of area 2 at δ 2.4. The singlet at δ 1.0 disappears on shaking with D2O. Determine the structure of the compound, and show the favorable fragmentation that accounts for the ion at m/z 30.

Short Answer

Expert verified

Structure of the compound:

Step by step solution

01

Structure determination from mass and IR spectrum data:

From mass spectrum data, you infer that, molecular ion peak is at m/z 87, which is odd mass and it means that odd number of nitrogen's are present.

If one nitrogen and no oxygen is present, then molecular formula will be C5H13N. Base peak is at m/z 30, thus structure must include the following fragment.

Fragment resulted from alpha cleavage.

02

Structure determination from NMR data:

From NMR data, we infer that, singlet is at chemical shift value 0.9 for 9 hydrogens, thus, it must be a tertiary butyl group. 2H signal at chemical shift value 1.0 exchanges with D2O, means, there must be proton on nitrogen or oxygen atom. From this you can conclude the structure of the compound.

Structure of the compound

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Start your free trial

Over 30 million students worldwide already upgrade their learning with Vaia!

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

The IR, NMR, and mass spectra are provided for an organic compound.

  1. Consider each spectrum individually, and tell what characteristics of the molecule are apparent from that spectrum.
  2. Propose a structure for the compound, and show how your structure fits the spectral data.
  3. Explain why an important signal is missing from the proton NMR spectrum.

Question: Phenols are less acidic than carboxylic acids, with values of around 10. Phenols are deprotonated by (and therefore soluble in) solutions of sodium hydroxide but not by solutions of sodium bicarbonate. Explain how you would use extractions to isolate the three pure compounds from a mixture of p-cresol (p-methylphenol), cyclohexanone, and benzoic acid.

Question: Rank the compounds in each set in order of increasing acid strength.

(a)CH3CH2COOH,CH3CHBrCOOH,CH3CBr2COOH

(b) CH3CH2CH2CHBrCOOH,CH3CH2CHBrCH2COOH,CH3CHBrCH2CH2COOH

(c)

,CH3CH2COOH,

Show how you would synthesize 2-phenylhex-3-yn-2-ol, starting with acetophenone (PhCOCH3 ) and any other reagents you need. (“2-ol” means there is an OH group on C2.)

Question:

  1. The Key Mechanism for Fischer esterification omitted some important resonance forms of the intermediates shown in brackets. Complete the mechanism by drawing all the resonance forms of these two intermediates.
  2. Propose a mechanism for the acid-catalyzed reaction of acetic acid with ethanol to give ethyl acetate.
  3. The Principle of Microscopic Reversibility states that a forward reaction and a reverse reaction taking place under the same conditions (as in equilibrium) must follow the same reaction pathway in microscopic detail. The reverse of the Fischer esterification is the acid-catalyzed hydrolysis of an ester. Propose a mechanism for the acid-catalyzed hydrolysis of ethyl benzoate, PhCOOCH2CH3.
See all solutions

Recommended explanations on Chemistry Textbooks

Chemical Analysis

Read Explanation

Chemical Reactions

Read Explanation

Ionic and Molecular Compounds

Read Explanation

Inorganic Chemistry

Read Explanation

Physical Chemistry

Read Explanation

Organic Chemistry

Read Explanation
View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.

Sign-up for free