Question

Draw a structural formula for each compound. (a) 1-Chloro-2-propanone (b) 3 -Hydroxybutanal (c) 4-Hydroxy-4-methyl-2-pentanone (d) 3-Methyl-3-phenylbutanal (e) 1,3 -Cyclohexanedione (f) 3 -Methyl-3-buten-2-one (g) 5-Oxohexanal (h) 2,2-Dimethylcyclohexanecarbaldehyde (i) 3-Oxobutanoic acid

Short answer

Question: Draw the structures for the following compounds and label them accordingly: (a) 1-Chloro-2-propanone (b) 3-Hydroxybutanal (c) 4-Hydroxy-4-methyl-2-pentanone (d) 3-Methyl-3-phenylbutanal (e) 1,3-cyclohexanedione (f) 3-Methyl-3-buten-2-one (g) 5-Oxohexanal (h) 2,2-Dimethylcyclohexanecarbaldehyde (i) 3-Oxobutanoic acid. Answer: (a) ClCH_2-CO-CH_3 (1-Chloro-2-propanone) (b) CH_3CH(OH)CH_2CHO (3-Hydroxybutanal) (c) CH_3COCH(CH_3)(OH)CH_2CH_3 (4-Hydroxy-4-methyl-2-pentanone) (d) CH_3CH(C_6H_5)(CH_3)CHO (3-Methyl-3-phenylbutanal) (e) ``` O=C C=O | | _|___ ___|__ / | \ | | | | \_______ ______/ ``` (1,3-Cyclohexanedione) (f) CH_3COCH=C(CH_3)_2 (3-Methyl-3-buten-2-one) (g) CH_3CH_2CH_2COCOCH_3 (5-Oxohexanal) (h) ``` HC=O CH3 | | _|___ _ _ ___|__ / | | \ |__CH3_ _ | | | +---- | \_______ ______/ ``` (2,2-Dimethylcyclohexanecarbaldehyde) (i) CH_3COCO2H (3-Oxobutanoic acid)

Step-by-step solution

(a) 1-Chloro-2-propanone

Identify the functional groups and substituents: Propanone is a 3-carbon ketone with the carbonyl group at the 2nd carbon. There is also a chlorine atom attached to the 1st carbon. Draw the structure: 1. Start by drawing a 3-carbon chain. 2. Add a carbonyl group (C=O) to the 2nd carbon. 3. Add a chlorine atom to the 1st carbon. The structural formula for 1-Chloro-2-propanone is: ClCH_2-CO-CH_3

(b) 3-Hydroxybutanal

Identify the functional groups and substituents: Butanal is a 4-carbon aldehyde with a hydroxyl group (-OH) at the 3rd carbon. Draw the structure: 1. Start by drawing a 4-carbon chain. 2. Add an aldehyde functional group (HC=O) to the 1st carbon. 3. Add a hydroxyl group (-OH) to the 3rd carbon. The structural formula for 3-Hydroxybutanal is: CH_3CH(OH)CH_2CHO

(c) 4-Hydroxy-4-methyl-2-pentanone

Identify the functional groups and substituents: This is a 5-carbon ketone with a carbonyl group at the 2nd carbon, a hydroxyl group (-OH), and a methyl group (-CH_3) at the 4th carbon. Draw the structure: 1. Start by drawing a 5-carbon chain. 2. Add a carbonyl group (C=O) to the 2nd carbon. 3. Add a hydroxyl group (-OH) and a methyl group (-CH_3) to the 4th carbon. The structural formula for 4-Hydroxy-4-methyl-2-pentanone is: CH_3COCH(CH_3)(OH)CH_2CH_3

(d) 3-Methyl-3-phenylbutanal

Identify the functional groups and substituents: This is a 4-carbon aldehyde with a methyl group (-CH_3) and a phenyl group (C_6H_5) attached to the 3rd carbon. Draw the structure: 1. Start by drawing a 4-carbon chain. 2. Add an aldehyde functional group (HC=O) to the 1st carbon. 3. Add a methyl group (-CH_3) and a phenyl group (C_6H_5) to the 3rd carbon. The structural formula for 3-Methyl-3-phenylbutanal is: CH_3CH(C_6H_5)(CH_3)CHO

(e) 1,3-Cyclohexanedione

Identify the functional groups and substituents: This is a cyclohexane ring with two carbonyl (C=O) groups at the 1st and 3rd carbons. Draw the structure: 1. Draw a cyclohexane ring. 2. Add carbonyl groups (C=O) to the 1st and 3rd carbons. The structural formula for 1,3-cyclohexanedione is: ``` O=C C=O | | _|___ ___|__ / | \ | | | | \_______ ______/ ```

(f) 3-Methyl-3-buten-2-one

Identify the functional groups and substituents: This is a 4-carbon ketone with a carbonyl group at the 2nd carbon, a double bond between the 3rd and 4th carbons, and a methyl group (-CH_3) at the 3rd carbon. Draw the structure: 1. Start by drawing a 3-carbon chain with a carbonyl group (C=O) at the 2nd carbon. 2. Add an additional carbon to the chain with a double bond to the 3rd carbon. 3. Add a methyl group (-CH_3) to the 3rd carbon. The structural formula for 3-Methyl-3-buten-2-one is: CH_3COCH=C(CH_3)_2

(g) 5-Oxohexanal

Identify the functional groups and substituents: This is a 6-carbon aldehyde with a carbonyl group (C=O) at the 1st carbon and another carbonyl group at the 5th carbon. Draw the structure: 1. Start by drawing a 6-carbon chain. 2. Add an aldehyde functional group (HC=O) to the 1st carbon. 3. Add a carbonyl group (C=O) to the 5th carbon. The structural formula for 5-Oxohexanal is: CH_3CH_2CH_2COCOCH_3

(h) 2,2-Dimethylcyclohexanecarbaldehyde

Identify the functional groups and substituents: This is a cyclohexane ring with an aldehyde functional group off of the 1st carbon and two methyl groups (-CH_3) at the 2nd carbon. Draw the structure: 1. Draw a cyclohexane ring. 2. Add an aldehyde functional group (HC=O) off of the 1st carbon. 3. Add two methyl groups (-CH_3) to the 2nd carbon. The structural formula for 2,2-Dimethylcyclohexanecarbaldehyde is: ``` HC=O CH3 | | _|___ _ _ ___|__ / | | \ |__CH3_ _ | | | +---- | \_______ ______/ ```

(i) 3-Oxobutanoic acid

Identify the functional groups and substituents: This is a 4-carbon carboxylic acid with a carbonyl group (C=O) at the 3rd carbon. Draw the structure: 1. Start by drawing a 4-carbon chain. 2. Add a carboxylic acid functional group (-COOH) to the 1st carbon. 3. Add a carbonyl group (C=O) to the 3rd carbon. The structural formula for 3-Oxobutanoic acid is: CH_3COCO2H