Discrimination of the two diastereoisomeric glycosides heterodendrin and epi-heterodendrin by the combined use of NOE and molecular mechanics

Biosynthesis of the leucine derived α‐, β‐ and γ‐hydroxynitrile glucosides in barley (Hordeum vulgare L.)

“…The HNGs used were obtained as follows: epiheterodendrin [2(R)-(b-D-glucopyranosyloxy)-3-methylbutanenitrile] (a-HNG) was synthesized as previously described (Lankhorst et al, 1995). Epidermin [3-(b-D-glucopyranosyloxy)-3-methylbutanenitrile] (b-HNG) and dihydroosmaronin [3(S)-4-(b-D-glucopyranosyloxy)-3-methylbutanenitrile] (c-HNG) were chemically synthesized by glucosylation of the corresponding aglucones 3-hydroxy-3-methybutanenitrile (commercially available from Sigma-Aldrich) and 3(S)-4-hydroxy-3methylbutanenitrile prepared from (R)-(À)-3-bromo-2-methyl-1propanol (commercially available from Sigma-Aldrich, St. Louis, MO, USA) by conventional procedures for conversion of halides into nitriles with inversion of configuration with 2,3,4,6-tetra-Oacetyl-D-glucopyranosyl fluoride as the glucosyl donor using boron trifluoroetherate as catalyst followed by chromatographic purification and deprotection to achieve the desired molecules (Zagrobelny et al, 2014).…”

An Antibacterial Isovaleronitrile Diglycoside From Detarium microcarpum Guill. Perr. (Fabaceae)

“…The fact that the 1 H NMR data of our compound (chemical shifts and coupling constants) (Table 2) show very close similarities to those of epihetrodendrine let us assign the «R» configuration to carbon C-2 as in the epihetrodendrine epimer. 21 Thus, from the above data, compound 1, to which the trivial name microcarposide was attributed, was assigned to be (2R) 3-meth…”

“…The fact that the 1 H NMR data of our compound (chemical shifts and coupling constants) (Table 2) show very close similarities to those of epihetrodendrine let us assign the « R » configuration to carbon C-2 as in the epihetrodendrine epimer. 21 Thus, from the above data, compound 1 , to which the trivial name microcarposide was attributed, was assigned to be (2 R ) 3-methyl-2-[β - l -rhamnopyranoside-1(1→6)-β - d -glucopyranosyl]butanenitrile or (2 R ) 2-[β - l -rhamnopyranoside-1(1→6)-β - d -glucopyranosyl]isovaleronitrile or 6ʹ- O -rhamnosyl-( R )-epiheterodendrine.…”

“…The fact that the 1 H NMR data of our compound (chemical shifts and coupling constants) (Table 2) show very close similarities to those of epihetrodendrine let us assign the «R» configuration to carbon C-2 as in the epihetrodendrine epimer. 21 Thus, from the above data, compound 1, to which the trivial name microcarposide was attributed, was assigned to be (2R Compounds 1 to 5 were assayed for their antibacterial potency against 3 Salmonella strains, Salmonella typhi (ST), Salmonella typhimurium (STM), and Salmonella enteritidis (SE). As depicted in Supplemental Table S1, only compound 1 exhibited a moderate activity against 3 strains, with minimum inhibition concentration (MIC) values of 153.4, 76.7, and 76.7 µM on ST, STM, and SE, respectively.…”