The key difference between oxazole and isoxazole is that oxazole has a nitrogen atom and oxygen atom separated by one carbon atom, whereas isoxazole has a nitrogen atom and oxygen atom adjacent to each other.
Oxazole and isoxazole are organic compounds having the same chemical formula and same molecular mass but different chemical structures. Therefore, these are isomers of each other. Their chemical formula is C3H3NO.
CONTENTS
1. Overview and Key Difference
2. What is Oxazole
3. What is Isoxazole
4. Oxazole vs Isoxazole in Tabular Form
5. Summary – Oxazole vs Isoxazole
What is Oxazole?
Oxazole is an organic compound having the chemical formula C3H3NO. It is a parent compound of a vast class of heterocyclic aromatic organic compounds. These compounds are azoles having an oxygen atom and a nitrogen atom separated by one carbon atom. Moreover, these are aromatic compounds, and oxazole can be described as a weak base. The conjugate acid of this compound has a pKa of 0.8. Also, the molar mass of oxazole is 69.06 g/mol. Further, the density of this compound is 1.050 g/cm3, and the boiling point is 69.5 degrees Celsius.
Figure 01: The Chemical Structure of Oxazole
When considering the preparation of oxazole, there are several classical oxazole synthetic methods in chemistry: Robinson-Gabriel synthesis (this method uses dehydration of 2-acylaminoketones), Fischer oxazole synthesis from cyanohydrins and aldehydes, Bredereck reaction (this method involves alpha-haloketones and formamide), and Van Leusen reaction (this reaction involves aldehydes and TosMIC).
Moreover, there are several important reactions oxazole can take part in. Some of these reactions are as follows:
- Deprotonation of oxazoles at C2 is accompanied by ring-opening to the isonitrile
- Electrophilic aromatic substitution occurs at the C5 position, which requires activating groups
- Nucleophilic aromatic substitution occurs at the C2 position with some leaving agents
- Cornforth rearrangement of 4-acyloxazoles (this is a thermal rearrangement reaction)
- Various oxidation reactions
What is Isoxazole?
Isoxazole is an organic compound having the chemical formula C3H3NO. It is an electron-rich azole having an oxygen atom adjacent to the nitrogen atom. It is a class of compounds that consists of a ring. This compound gives a univalent radical named isoxazole.
Figure 02: The Chemical Structure of Isoxazole
The molar mass of this compound is 69.062 g/mol. The density of this compound can be given as 1.075 g/cm3. Its boiling point can be given as 95 degrees Celsius. It occurs in some natural products, including ibotenic acid and muscimol.
Moreover, isoxazole can be synthesized by a variety of methods such as the use of 1,3-dipolar cycloaddition of nitrile oxides with alkynes, the reaction of hydroxylamine with 1,3-diketones or derivatives of propiolic acid, etc.
What is the Difference Between Oxazole and Isoxazole?
Oxazole and isoxazole are isomers of each other, having the same chemical formula and same molar mass. The key difference between oxazole and isoxazole is that oxazole has a nitrogen atom and oxygen atom separated by one carbon atom, whereas isoxazole has a nitrogen atom and oxygen atom adjacent to each other. When considering their acidity, oxazole has a pKa value of 0.8 whereas isoxazole has a pKa value of -3.0.
The below infographic presents the differences between oxazole and isoxazole in tabular form for side-by-side comparison.
Summary – Oxazole vs Isoxazole
Both oxazole and isoxazole are organic compounds having the same chemical formula, C3H3NO. These are isomers of each other. The key difference between oxazole and isoxazole is that oxazole has a nitrogen atom and oxygen atom separated by one carbon atom, whereas isoxazole has a nitrogen atom and oxygen atom adjacent to each other.
Reference:
1. “Isoxazole.” National Center for Biotechnology Information. PubChem Compound Database, U.S. National Library of Medicine.
Image Courtesy:
1. “Oxazole 2D numbered” By Jynto (talk) – This structural formula was created with ChemDraw. (CC0) via Commons Wikimedia
2. “Isoxazole 2D numbered” By Jynto (talk) – This structural formula was created with ChemDraw. (CC0) via Commons Wikimedia
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