PEG-Supported Synthesis of 3,5-Disubstituted 1,2,4-Triazoles

Abstract

1,3-Dipolar cycloadditions between diethyl azodicarboxylate and the polymer-bound munchnones generated from the corresponding carboxylic acids provided a library of 3,5-disubstituted 1,2,4-triazoles in excellent yield and high purity.

Key words

PEG-bound munchnones - diethyl azodicarboxylate - cycloadditions - 1,2,4-triazoles - parallel synthesis

References

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6

The polymer-bound 1 was characterized by 200 MHz ¹H NMR analysis in CDCl₃: δ = 3.08 (3 H, s, CH₃SO₂), 3.52-3.74 (PEGO-CH₂CH₂O, m). The polymer-bound 2 was characterized by 200 MHz ¹H NMR analysis in CDCl₃: δ = 3.66-3.87 (PEG, m), 4.20 (t, 2 H, -PEGOCH₂CH ₂OC=O), 6.42 (1 H, d), 6.47 (1 H, d,) 7.38 (1 H, d), 8.59 (1 H, s).

7

All the compounds were characterized and their structures were confirmed by spectrometric methods (¹H NMR, ¹³C NMR, MS) and elemental analysis. Compound 7f is as follow: ¹H NMR (400MHz, CD₃OD): δ = 3.84 (3 H, s), 7.03-7.06 (2 H, dt, J = 2.4, 9 Hz), 7.47-7.50 (3 H, m), 7.96-7.99 (2 H, dt, J = 2.4, 9 Hz), 8.04-8.07 (2 H, m); ¹³C NMR (CD₃OD): δ = 56.1, 115.5, 115.6, 127.8, 129.4, 129.4, 130.3, 130.6, 131.2, 131.4, 162.9; MS (EI): m/z = 251 (M⁺); Anal. Calcd for C₁₅H₁₃N₃O: C, 71.70; H, 5.21; N, 16.72. Found: C, 71.52; H, 5.29; N, 16.64.