Comparison of H2BC and 1,1-ADEQUATE

H2BC (Heteronuclear 2-Bond Correlation) and 1,1- ADEQUATE (Adequate Sensitivity DoublE QUAntum Transfer Experiment) are used to detect 2-bond C-H correlations when it is difficult to differentiate 2-bond correlations from 3-bond correlations by a combination of COSY and HMBC experiments. Here we compare the major features of H2BC and 1,1-ADEQUATE.

4-Methylumbelliferone

H2BC is a more sensitive experiment than 1,1-ADEQUATE. However, H2BC does not show correlations between protons and quaternary carbons. Therefore, when analyzing compounds that have many quaternary carbons, such as 4-methylumbelliferone, 1,1-ADEQUATE can provide many more correlations than H2BC. On the other hand, 1,1-ADEQUATE requires careful optimization of the ¹J_CC delay according to the chemical structure.

【H2BC】

• Observe ²J_CH correlations only
• Higher sensitivity than 1,1-ADEQUATE
• Cannot observe correlations between protons and quaternary carbons
• Careful optimization of parameters not required

H2BC, 4 scans, 25 mins

【1,1-ADEQUATE】

• Observe ¹J_CH, ²J_CH correlations
• Lower sensitivity than H2BC
• Observe quaternary carbons
• Careful optimization of ¹J_CC required

1,1-ADEQUATE, 48 scans, 7 hrs

Instrument: JNM-ECZ400S, ROYALPROBE™
Sample: 100mg 4-methylumbelliferone in DMSO-d6

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