Draw a structure for each of the following: a. 2 -hexyne b....

Name: Problem 23, Chapter 6: Organic Chemistry
Uploaded: 2020-12-30T03:28:35-08:00
Duration: 8 min 50 s
Channel: Dr. Satish Ingale
Description: Draw a structure for each of the following: a. 2 -hexyne b. 5 -ethyl- 3 -octyne c. methylacetylene d. vinylacetylene e. methoxyethyne f. sec-butyl-tert-butylacetylene g. 1 -bromo-1-pentyne h. propargyl bromide i. diethylacetylene j. di-tert-butylacetylene k. cyclopentylacetylene l. 5,6 -dimethyl- 2 -heptyne

Draw a structure for each of the following: a. 2 -hexyne b. 5 -ethyl- 3 -octyne c. methylacetylene d. vinylacetylene e. methoxyethyne f. sec-butyl-tert-butylacetylene g. 1 -bromo-1-pentyne h. propargyl bromide i. diethylacetylene j. di-tert-butylacetylene k. cyclopentylacetylene l. 5,6 -dimethyl- 2 -heptyne

Draw a structure for each of the following:
a. 2 -hexyne
b. 5 -ethyl- 3 -octyne
c. methylacetylene
d. vinylacetylene
e. methoxyethyne
f. sec-butyl-tert-butylacetylene
g. 1 -bromo-1-pentyne
h. propargyl bromide
i. diethylacetylene
j. di-tert-butylacetylene
k. cyclopentylacetylene
l. 5,6 -dimethyl- 2 -heptyne

Key Concepts

Alkynes

Alkynes are hydrocarbons characterized by one or more carbon–carbon triple bonds. They are sp-hybridized at the carbons involved in the triple bond, which gives the bond a linear geometry. Understanding the structure and reactivity of alkynes is fundamental in organic chemistry as they undergo unique reactions like electrophilic addition and coupling reactions.

IUPAC Nomenclature for Alkynes

The IUPAC rules for naming alkynes require identifying the longest continuous carbon chain that includes the triple bond. The chain is numbered so that the triple bond receives the lowest possible locant. Names are then constructed by combining prefixes that denote substituents with the base name that indicates the chain length and the position of the triple bond, ensuring a systematic and unambiguous representation of the molecule's structure.

Substituent Positioning and Numbering

When drawing the structures based on IUPAC names, substituents (such as alkyl, bromo, or methoxy groups) are placed at positions indicated by numbers in the compound’s name. The numbering of the carbon chain starts from the end nearest to the triple bond, ensuring that the multiple bonds and substituents are assigned the lowest possible numbers. This concept is crucial for accurately depicting isomeric relationships and ensuring clarity in molecular structure.

Structural Representation and Diagramming

In drawing the structures for alkynes and their substituted derivatives, it is important to represent the triple bond correctly (using a linear notation or triple line) and indicate substituent groups at their appropriate locations along the carbon chain. Proper structural diagrams reflect the connectivity, functional groups, and stereochemistry if applicable, ensuring that the drawn molecule corresponds exactly to the IUPAC name provided.

Transcript

0:00 Hi everyone.

00:01 So in order to tackle this question, first one is two hexine.

00:08 Two hexine.

00:09 It's very simple.

00:10 That is first draw six carbon items, three, four, five and six.

00:15 Now, you know, then draw a single bond.

00:21 Then next one is two keyway numbering.

00:24 So this is the first carbon, second carbon, third.

00:27 You can say fourth, fifth and sixth.

00:29 So draw triple bond at second position.

00:34 Then number of hydrogens satisfy the valency of carbon using number of hydrogen.

00:40 So number of hydrogen is equal to 4 minus actual bond present.

00:44 So here 4 minus 1, 3.

00:48 Then here 4 minus 2.

00:53 2.

00:54 Make here 4 minus 2 2 and this is 4 minus 1 3.

00:58 So this is structure of xx.

01:00 Then second, 5 ethyl.

01:06 3 octane 5 ethyl 3 octane so draw 1 1 3 carbine 1 2 3 4 4 5 6 7 8 then draw a single bond the next give numbering 1 2 3 4 5 6 7 8 now three octane means you have to draw a triple bond between third and fourth carbon and phythyl so put ethyl sustenoned at fifth carbon then satisfy valency of carbon you know it is four minus one so it is three then this is four minus two two then four minus four zero zero so here four minus three one then here is four minus two two then four minus two and this is so this one, the structure.

02:10 The next structure, methyl acetylene.

02:15 Methylacetylene.

02:16 It's a common name.

02:18 So, you have tried here, methyl and then acetylene, cs3c, triple bond, c, h...

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