Complete assignments of 1H and 13C NMR data for three new arylnaphthalene lignan from Justicia procumbens

Three new arylnaphthalene lignans, named neojusticin C (1), procumbenoside C (2) and procumbenoside D (3), have been isolated from the whole plant of Justicia procumbens, together with three known ones, justicidinoside B (4), justicidinoside C (5), and diphyllin-1-O-beta-D-apiofuranoside (6). The complete assignments of (1)H and (13)C NMR data for three new lignans were first obtained by means of 2D NMR techniques, including HSQC and HMBC. Copyright (C) 2008 John Wiley & Sons, Ltd.