(+)‐N‐Formylnorglaucine Rotamers from Unonopsis stipitataDiels

Abstract

(+)-N-formylnorglaucine (1), an aporphine alkaloid containing a formyl group linked to the heterocyclic nitrogen, was isolated from the leaves of Unonopsis stipitata, an Amazon medicinal plant. The chemical structure was characterized based on 1D-and 2D-NMR spectroscopy and HR-ESI-MS. NMR spectra revealed that 1 is composed of two rotamers (1a and 1b) in a ratio of approximately 2:1. In addition, the fragmentation behavior of 1 displayed an unusual fragmentation pattern compared to regular aporphine alkaloids. Thus, this compound is reported for the first time as a natural product in this study.

Biologically active isoquinoline alkaloids covering 2014–2018

“…In addition to M. aquifolium, it is found in lotus (Nelumbo nucifera) seed embryos. 51 In 2018, compound 61 as well as four other bisbenzylisoquinoline alkaloids, liensinine (62), isoliensinine (63), norisoliensinine (64), and 6-hydroxynorisoliensinine (65) were found in P. nelumbinis. 30 Five alkaloids also were isolated from Alseodaphne corneri, including (−)-gyrolidine (66), (+)-O-methyllimacusine (67), (+)-2-norobaberine (68), (+)-norstephasubine (69), and (+)-stephasubine (70) 52 ( Figure 4).…”

“…40 (+)-N-Formylnorglaucine (114) was reported from Unonopsis stipitata. 62 Four new phenyl-C 1 substituted aporphine alkaloids, 6aR-2′-methoxycarbonylthaliadine (115), 6aR-2′carboxylthaliadine (116), 6aR-3-methoxyhernandalinol (117), 6aS-1,3,10-trimethoxynatalamine (118), together with three known isoquinoline alkaloids 89, predicentrine (119), and thaliadine (120) were isolated from the whole herb of T. cirrhosum. 43 Glaucine 121 wangii 46 ( Figure 5).…”

“…Compounds 97, 98, 109 , and 112 were found in Unonopsis duckei , 59 and compounds 89, 96, 97 , and 109 were reported from B. pleiosperma 40 . (+)‐ N ‐Formylnorglaucine ( 114 ) was reported from Unonopsis stipitata 62 …”

Anthocyanidins structural study using positive electrospray ionization triple quadrupole mass spectrometry and H/D exchange

“…The skeleton of cyanidin, delphynidin, and pelargonin derivatives are usually present in nature as glycosylated unstable species (anthocyanins) that may be have the stability improved toward acetylation reaction . The clear industrial interest for such interesting class of compounds makes the study of structure features beneficial for improved methods for fast analysis using neutral loss and/or precursor ion scan experiments in dereplication procedures for complex vegetable matrices by mass spectrometry (MS) …”

“…3 The clear industrial interest for such interesting class of compounds makes the study of structure features beneficial for improved methods for fast analysis using neutral loss and/or precursor ion scan experiments in dereplication procedures for complex vegetable matrices by mass spectrometry (MS). 4,5 For a long time, electrospray ionization mass spectrometry (ESI-MS) has been used for anthocyanins analysis, 6 including screening for anthocyanins with HPLC coupled to tandem mass spectrometry (MS/MS) using precursor-ion, product-ion, neutral-loss, and selected reaction monitoring modes 7 and capillary electrophoresis/mass spectrometry (CE/MSn) for the study of anthocyanin dyes; otherwise, there is no mechanistic fragmentation study for the cleavages proposed. 8 Recent methods that use mass spectrometric analysis for anthocyanins determination have been reported 9,10 without discussing fundamental mass spectrometric fragmentation aspects.…”