Experimental determination of structure, pharmaceutical chemistry Flashcards

1
Q

What can elemental microanalysis (/combustion analysis) be used to determine

A

Empirical formula of an organic compound

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2
Q

Describe the process of elemental microanalysis

A

A tiny sample is accurately weighed and oxidised at a high temperature in an oxygen rich atmosphere
The product mixture of CO2, H2O, N2, SO2 is separated using gas chromatography and the mass of each component is measured using a thermal conductivity detector

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3
Q

What is mass spectrometry used for

A

A technique to determine the accurate molecular mass and structural features of a compound

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4
Q

What happens to the sample being analysed in a mass spectrometer

A

It is vaporised and and bombarded with high energy electrons which knocks electrons off the molecule and as a result the molecules break into positively charged ion fragments

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5
Q

What happens to the positively charged ion fragments in a mass spectrometer

A

They’re accelerated by a high voltage electric field into a strong magnetic field that deflects them into a series of separate ion paths according to their mass/charge ratio.

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6
Q

What is the difference between positive ion fragments with a lower or higher mass/charge ratio

A

Ions with lower mass/charge ratios are deflected more than those with higher ratios

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7
Q

What are the common types of bond vibration

A

Stretching and bending

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8
Q

What affect does infrared radiation have on bonds

A

Causes them to vibrate but not break

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9
Q

What determines the wavelenght of infrared radiation that a bond absorbs

A

The type of atoms and the stiffness (strength) of the bond

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10
Q

In general, which bonds absorb infrared radiation with a shorter wavelength

A

Light atoms with stiff bonds

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11
Q

What does infrared spectroscopy make use of

A

Identifies the atoms and bond strength of a bond to identify specific bonds and functional groups

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12
Q

Describe the process of infrared spectroscopy

A

Infrared radiation is passed through the sample in a spectrometer, Some wavelengths are absorbed causing bonds to vibrate.
The transmitted radiation passes to a detector where the intensity of different wavelengths is measured.

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13
Q

Explain why protons behave like tiny magnets when placed between the poles of a powerful magnet

A

Some atomic nuclei spin about their own axes

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14
Q

Whats the energy of protons aligned with the magnetic field compared to those aligned against it

A

Protons aligned with the field have lower energy

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15
Q

What corresponds to the radio frequency region of the electromagnetic spectrum with reference to proton nuclear magnetic resonances spectroscopy

A

The energy difference between protons aligned with and against the magnetic field

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16
Q

What happens when protons are exposed to radio waves

A

Energy is absorbed to promote those in lower energy state to the higher energy state
The protons flip from being aligned with the magnetic field to being aligned against it

17
Q

What is proton nuclear magnetic resonance

A

When protons fall back to a lower energy state and emit energy with the same frequency as what they absorbed (radio waves) - can be measured with a radio reciever

18
Q

What does proton nuclear magnetic resonance spectroscopy tell us

A

How many different chemical environments the protons in an organic molecule molecule can exist
How many protons are in each of these environments
The type of proton environment

19
Q

Wha is the common standard in 1H NMR spectroscopy

A

TMS - Tetramethylsilane

20
Q

What does 1H NMR stand for

A

Proton nuclear magnetic resonance

21
Q

Define chemical shift

A

The difference between protons in TMS and the protons in other chemical environments

22
Q

What is chemical shift measured in

A

Parts per million (ppm)

23
Q

Whats the difference in high resolution 1H NMR spectroscopy and regular 1H NMR spectroscopy

A

High resolution 1H NMR spectroscopy uses radio waves of a higher frequency which results in a more detailed spectra being produced

24
Q

What are the multiple peaks of a high resolution 1HMR spectroscopy graph called

A

Multiplets

25
Q

What does it mean if there is more than one peak in a proton environment and how are they caused

A

There must be hydrogen atoms within that environment experiencing slightly different magnetic fields
Caused by the influence of the hydrogen atom on the neighbouring carbon atom (as hydrogens have a magnetic field of their own)

26
Q

What does the additional detail of a high resolution 1HMR spectrum provide us with

A

Allows the neighbouring proton environment to be identified

27
Q

What is the n + 1 rule

A

A way of identifying the neighbouring proton environment where n is the number of hydrogen atoms atoms attached to the next door carbon atom and n + 1 is the number of peaks in the cluster

28
Q

What is a drug

A

A substance that can have biochemical processes in the body

29
Q

What is a medecine

A

A drug which has a beneficial effect

30
Q

What may be added to some medecines

A

A filter if the active ingredient is very small
A sweetner
A coat - to be swallowed

31
Q

List some examples of ancient medecines

A

The bark of willow - lessens pain, fever, inflammation
Opium as painkiller/sedative
Cinchona bark for malaria

32
Q

What is an agonist

A

A substance that will produce a response similar to the bodies natural active compound

33
Q

What is an antagonist

A

A substance that produces no response but prevents the action of the body’s natural active compound

34
Q

How do drugs work

A

By binding to receptors

35
Q

What is a receptor

A

Receptors are protein molecules on the surface of cells where they interact with biologically active molecules, or are enzymes that catalyse chemical reactions

36
Q

What is critical about the shape of a drug

A

It has to fit its binding site

37
Q

How do drugs usually work

A

Many drugs act as enzyme inhibitors by binding to the
enzyme’s active site and blocking the reaction normally
catalysed there

38
Q

What are the main types of bonding between a drug and its receptors binding site

A

Van der waal’s and ionic usually

39
Q

What can a sulfonamide be if active

A

An antibacterial agent