Selective J‐resolved HMBC,an efficient method for measuring heteronuclear long‐range coupling constants |
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| Authors: | Kazuo Furihata Mitsuru Tashiro Haruo Seto |
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| Institution: | 1. Division of Agriculture and Agricultural Life Sciences, The University of Tokyo, Yayoi, Bunkyo‐ku, Tokyo 113‐8657, Japan;2. Department of Chemistry, College of Science and Technology, Meisei University, Hino, Tokyo 191‐8506, Japan;3. Faculty of Applied Bioscience, Tokyo University of Agriculture, Setagaya‐ku, Tokyo 156‐8502, Japan |
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| Abstract: | An efficient pulse sequence for measuring long‐range C? H coupling constants (JC? H) named selective J‐resolved HMBC has been developed by replacing a 1H 180° pulse with a selective 1H 180° pulse and the HMBC pulse scheme with the constant time (CT) HMBC employed in the J‐resolved HMBC pulse sequence that we reported previously. The novel pulse sequence providing only long‐range JC? H cross peaks for easy and accurate analysis enables to overcome disadvantages of the previous HMBC‐based pulse sequences (J‐resolved HMBC‐1) along with maintaining high sensitivity. The efficiency of measuring long‐range JC? H using the proposed pulse sequence has been demonstrated in applications to the complicated natural products, portmicin and monazomycin. Copyright © 2009 John Wiley & Sons, Ltd. |
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| Keywords: | NMR 1H 13C NMR J‐resolved HMBC selective J‐resolved HMBC CT‐HMBC heteronuclear long‐range coupling constants |
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