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Date: 6-9-2019
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An amine is an organic derivative of ammonia (NH3). In amines, one or more of the H atoms in NH3 is substituted with an organic group. A primary amine has one H atom substituted with an R group:
A secondary amine has two H atoms substituted with R groups:
A tertiary amine has all three H atoms substituted with R groups:
Naming simple amines is straightforward: name the R groups as substituents and then add the suffix –amine, using numerical suffixes on the substituent names as necessary. This amine is diethylamine.
This amine is ethyldipropylamine.
Name this amine.
Solution
This amine has a methyl group, an ethyl group, and a propyl group. Listing the names in alphabetical order, this amine is ethylmethylpropylamine.
Test Yourself
Name this amine.
Answer
triethylamine
As with NH3, the N atom in amines can accept a proton onto the lone electron pair on the N atom. That is, amines act as Brønsted-Lowry bases (i.e., proton acceptors):
(For more information on Brønsted-Lowry bases, see Section 12.2 “Brønsted-Lowry Acids and Bases”.) The amine becomes an ion, the organic counterpart of the ammonium (NH4+) ion.
Because no amine is presented in Table 12.2 “Strong Acids and Bases,” all amines are weak bases. The weakness of amines is about the same as that of carboxylic acids. N-containing organic compounds are very common in nature, and they all act as weak bases. Some of these compounds have rather complicated structures. Figure 16.5 “Some Naturally Occurring N-Containing Compounds” shows some N-containing substances that you may recognize.
Figure 16.5 Some Naturally Occurring N-Containing Compounds
An amide functional group is a combination of an amine group and a carbonyl group:
Amides are actually formed by bringing together an amine-containing molecule and a carboxylic acid-containing molecule. A molecule of H2O is lost, much like when an ester forms:
The bond between the N of the amine group and the C of the carbonyl group is called an amide bond. Amide bonds are particularly important in biological molecules called proteins, which are composed of strings of amino acids—molecules that have an amine group and a carboxylic acid group in them. The amine group on one amino acid reacts with the carboxylic acid group of another amino acid, making a chain held together by amide bonds. We will consider proteins later in this chapter.
Draw the structure of the amide formed by the combination of ethylamine and butanoic acid.
Solution
The structures of ethylamine and butanoic acid are:
When they come together to make an amide, an H2O molecule is lost, and the N of the amine group bonds to the C of the carboxyl group. The resulting molecule is:
Test Yourself
Draw the structure of the amide formed by the combination of methylamine and formic acid.
Answer
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تفوقت في الاختبار على الجميع.. فاكهة "خارقة" في عالم التغذية
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أمين عام أوبك: النفط الخام والغاز الطبيعي "هبة من الله"
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المجمع العلمي ينظّم ندوة حوارية حول مفهوم العولمة الرقمية في بابل
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