Benzyl isobornyl amines: a simple and practical class of NMR discriminating agents for effective chiral recognition of acids

Bioassay‐Guided Isolation of Antifungal Compounds from Disporopsis aspersa (Hua) Engl. ex Diels against Pseudoperonospora cubensis and Phytophthora infestans

“…The other 12 known compounds were established as pyroglutamic acid, adenosine, N ‐benzoyltryptamine, α ‐hydroxybenzeneacetic acid, salicylic acid, stearic acid, 6‐isopropyl‐3‐methylphenol, β ‐sitosteryl glucopyranoside, stigmasterol 3‐ O ‐ β ‐ d ‐glucopyranoside, β ‐sitosterol, quercetin, and rutin, by comparing their spectroscopic data with those in the literature.…”

“…The position of hydroxy group at A ring was characterized by HSQC (3. [18] Furthermore, by analysis of the 13 C-NMR spectrum of 1, the characteristic signals for C(3), C(5), C(6), C(22), C(25), and C(26) (d(C) 78.8, 147.4, 127.4, 108.9, 31.4, and 66.4) indicated that the configuration of the aglycone of 1 was in good accordance with that of (3b,25S)-spirost-5-en-3-yl b-D-glucopyranoside. [18 -21] The configuration at C(22) was confirmed to be (S), based on the comparison of the 13 C-NMR data of C (22) and NMR data of C(23), C(24), C (25), and C (26). [19] [21] This supposition was confirmed by 2D-NMR experiments (HSQC, HMBC, COSY, NOESY).…”

5-Nitro-N 2,N 3-bis[(1R,2R,4R)-1,7,7-trimethylbicyclo[2.2.1]heptan-2-yl]isophthalamide dichloromethane hemisolvate

“…The principle of the separation of signals for the enantiomers of the analyte is based on supramolecular interactions with the chiral additive such as hydrogen bonding, C-HÁ Á Á,interactions, etc. We have recently reported a chiral camphor-based Kagan's amide and explored its activity for estimation of enantiomer ratios of a wide variety of functionalized molecules (Kannappan et al, 2015(Kannappan et al, , 2017. As part of our ongoing studies in this area, we now report the synthesis and structure of the title compound (Fig.…”

Optically Pure Aziridin-2-yl Methanols as Readily Available 1H NMR Sensors for Enantiodiscrimination of α-Racemic Carboxylic Acids Containing Tertiary or Quaternary Stereogenic Centers

“…The study of the recognition of chiral carboxylic acids and their derivatives are of interest to many research groups due to the fact that such molecules are basic building blocks of many natural products and drug molecules. 12 In the past decades, various CSAs such as chiral and prochiral amines, 13 “calixarene-like” chiral amine systems 14 and other macrocyclic amines and amides, 15 amino alcohols, 16 salene derivatives, 17 crown or aza-crown ethers, 18 l -proline derivatives, 19 BINOL and their derivatives, 20 chiral shift reagents derived from squaramide and indanol, 21 1,2-diaminocyclohexane derivatives, 22 and chiral bisthioureas 23 have been reported particularly for mandelic acid, its derivatives, and other α-hydroxy acids. Although variously modified amine systems have been successfully used as CSAs, just one example of an optically active aziridine-derived receptor for the enantiodiscrimination of α-racemic carboxylic acids can be found in the literature.…”