Oxone-Mediated Mild Removal of an Azine Protecting/Directing Group for Applications in Organic Synthesis

Gokul Ganesan; Pownthurai Balasubramaniam; Mukeshkumar Yadav; Hardik Janwadkar; Abhijit Papalkar; Atul Chaskar

doi:10.1055/a-2604-4702

Synlett, Table of Contents

Synlett 2025; 36(13): 1927-1931
DOI: 10.1055/a-2604-4702

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Oxone-Mediated Mild Removal of an Azine Protecting/Directing Group for Applications in Organic Synthesis

Authors

Gokul Ganesan‡

^aNational Center for Nanosciences and Nanotechnology, University of Mumbai, Vidyanagari, Mumbai 400098, Maharashtra, India

^cDepartment of Chemistry, Jai Hind College Autonomous, ‘A’ Road, Churchgate, Mumbai 400020, Maharashtra, India
Pownthurai Balasubramaniam‡

^aNational Center for Nanosciences and Nanotechnology, University of Mumbai, Vidyanagari, Mumbai 400098, Maharashtra, India
Mukeshkumar Yadav‡

^aNational Center for Nanosciences and Nanotechnology, University of Mumbai, Vidyanagari, Mumbai 400098, Maharashtra, India
Hardik Janwadkar

^bDepartment of Chemistry, Institute of Chemical Technology, N.P. Marg, Matunga, Mumbai 400019, India
Abhijit Papalkar

^dDepartment of Chemistry, Fergusson College, F.C. Road, Pune 411004, Maharashtra, India
Atul Chaskar∗

^bDepartment of Chemistry, Institute of Chemical Technology, N.P. Marg, Matunga, Mumbai 400019, India

Abstract

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Abstract

Azine derivatives of carbonyl compounds are used as protecting groups and have recently been utilized as directing groups in C–H activation. The stability of the azine functional group limits its application in areas where its subsequent removal is desirable. We herein report a mild and efficient method for removal of an azine group using Oxone as a green oxidant in the presence of an acetone/water solvent system. Carbonyl regeneration occurs in high yields from a range of aldazine and ketazine derivatives. A gram-scale synthesis and removal of the azine directing group from an ortho-functionalized azine are performed to extend the application of this methodology.

Key words

azines - oxidative deprotection - Oxone - directing groups - carbonyl compounds

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References

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29 Azine Directing Group Removal; General Procedure A round-bottomed flask was charged with Oxone (1.74 g, 6 equiv) in H₂O (7.5 mL). A solution of the corresponding azine-protected carbonyl substrate (0.95 mmol) in acetone (7.5 mL) was added dropwise to the flask and the resulting mixture was allowed to stir at room temperature until completion of reaction (monitored by TLC). The reaction was quenched by adding H₂O (20 mL) and extracted using ethyl acetate. The organic layer was dried over sodium sulfate and evaporated under reduced pressure. The obtained product was dried under vacuum.
30 3-(Trifluoromethyl)benzaldehyde (2i) Time required for conversion: 40 min. ¹H NMR (400 MHz, CDCl₃): δ = 10.00 (d, J = 1.0 Hz, 1 H), 8.06 (s, 1 H), 8.01 (d, J = 7.8 Hz, 1 H), 7.80 (d, J = 7.9 Hz, 1 H), 7.62 (t, J = 7.8 Hz, 1 H). ¹³C NMR (101 MHz, CDCl₃): δ = 190.82, 136.82, 132.74, 130.69, 129.79, 126.23, 124.88, 122.14. MS (ESI): m/z = 174.03.
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Supplementary Material

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