Rapid Approaches for Assignment of the Relative Configuration in 1-Oxygenated 1,2-Diarylpropan-3-ols by ¹H NMR Spectroscopy

Abstract

The structural elucidation of chiral molecules with more than one stereocenter is usually a tricky problem. In this paper, efficient 1H NMR spectroscopic approaches for assigning the erythro and threo configurations of 1-oxygenated 1,2-diarylpropan-3-ols were developed. By analysis of the chemical shift differences of diastereotopic methylene H2-3 (Δδ3) in CDCl3 or the chemical shift differences of H-1 and H-2 (Δδ1,2) in methanol-d 4, deuterated dimethyl sulfoxide, and acetone-d 6, the configurations of 1-oxygenated 1,2-diarylpropan-3-ols can be rapidly and conveniently determined.

Five New Phenolic Glycosides from Viburnum luzonicum

“…[8] The linkage position of 3'',5''-dimethoxyphenyl moiety at C-2 was . [9] The Δδ 1,2 value of 1 was about 2.19 ppm, which suggested that compound 1 has a erythro configuration. The absolute configuration of 1 was elucidated as 1S,2R by the experimental and calculated ECD spectra analysis (Figure 3).…”

“…The linkage position of 3′′,5′′‐dimethoxyphenyl moiety at C‐2 was also confirmed by the HMBC cross‐peaks from 3′′/5′′‐OCH 3 ( δ H 3.66) and H‐2′′/6′′ ( δ H 6.35) to C‐3′′/5′′ ( δ C 159.5) and from H‐2 ( δ H 2.94) to C‐1′′ ( δ C 142.5) and C‐3′′/5′′. The chemical shift differences of H‐1 and H‐2 (Δ δ 1,2 ) were applicable in distinguishing threo ‐ and erythro ‐1‐oxygenated 1,2‐diarylpropan‐3‐ols [ threo (Δ δ 1,2 <1.95 ppm) and erythro (Δ δ 1,2 >2.00 ppm) in DMSO‐ d 6 [9] . The Δ δ 1,2 value of 1 was about 2.19 ppm, which suggested that compound 1 has a erythro configuration.…”

Study on Components with Neuroinflammation Inhibitory Activities from Croton tiglium L. var. xiaopadou

“…By comparing the data with the published articles, and considering their physical and spectroscopic data, it was determined that the known compounds are 4‐hydroxy‐4,7‐dimethyl‐1‐tetralone ( 2 ), [15] (−)‐loliolide ( 3 ), [16] limonin ( 4 ), [17] diosgenin ( 5 ), [18] guaiacylglycerol 8′‐vanillin ether ( 6 ), [19] coriarianeolignan A ( 7 ), [20] thero ‐2,3‐bis(4‐hydroxy‐3‐methoxyphenyl)‐3‐methoxypropanol ( 8 ), [21,22] 1,2‐bis(4‐hydroxy‐3‐methoxyphenyl)propane‐1,3‐diol ( 9 ), [23] evofolin B ( 10 ), [24] cleomiscosin B ( 11 ), [25] cleomiscosin A ( 12 ), [25] cleomiscosin C ( 13 ), [26] honokiol ( 14 ), [27] (−)‐guaiacylglycerol‐ β ‐ O‐ 4′‐coniferyl ether ( 15 ), [28] 1‐(4‐hydroxy‐3‐methoxyphenyl)‐2‐[3‐(3‐hydroxy‐1‐propen‐1‐yl)‐5‐methoxyphenoxy]‐1,3‐propanediol ( 16 ), [29] ficusal ( 17 ), [30] (−)‐jatrointelignan D ( 18 ), [31] (−)‐simulanol ( 19 ), [32] (+)‐dehydrodiconiferyl alcohol ( 20 ), [33] (+)‐medioresinol ( 21 ), [34–36] threo ‐ficusesquilignan A ( 22 ), [37] erythro ‐ficusesquilignan A ( 23 ), [32,34,37] hedyotisol A ( 24 ), [34,38] hedyotisol B ( 25 ), [32,39] naringenin ( 26 ), [40] oroxylin A ( 27 ), [41] kaempferol ( 28 ), [42] rutin ( 29 ), [43] hinokiflavone ( 30 ), [44] isofraxidin ( 31 ), [45] scopoletin ( 32 ), [46] N‐trans‐ feruloyltyramine ( 33 ), [47] and rutaecarpine ( 34 ) [48]…”