5798-67-4Relevant academic research and scientific papers
Structural analysis of pentacyclic triterpenes from the gum resin of Boswellia serrata by NMR spectroscopy
Belsner, Klaus,Buechele, Berthold,Werz, Udo,Syrovets, Tatiana,Simmet, Thomas
, p. 115 - 122 (2003)
3α-Acetyl-β-boswellic acid (1), 3α-acetyl-α -boswellic acid (2), 3α-acetyl-9,11-dehydro-β-boswellic acid (3), 3α-acetyl-9,11-dehydro-α-boswellic acid (4) and 3α -acetyl-11-keto-β-boswellic acid (5) were isolated from the gum resin of Boswellia serrata. 1D and 2D NMR (COSY45, HMQC, HMBC, ROESY) spectra at 500 MHz were used for shift assignments and structure verification. All boswellic acids investigated share the cis conformation at ring D/E and the 3α orientation of the acetyl ester group. Owing to high-order spectra, NMR could not determine the exact conformation of H-20/H-30 of the β-boswellic acids. 3α-Acetyl-β-boswellic acid methyl ester (1′) was synthesized for experiments with a shift reagent, Eu(fod)3, that enhanced the resolution considerably. The oxygen atoms of the 3α-acetyl group form the apparent complex binding site for the shift reagent. Copyright
Reagent optimization for allylic oxidation of 3-O-acetyl-β-boswellic acid into 3-O-acetyl-11-oxo-β-boswellic acid
Shenvi, Suvarna,Reddy, G. Chandrasekara
, (2013)
Introduction of the oxo group at the allylic position of 3-acetoxy-urs-12-en-24β-oic acid (ABA) in the presence of the sensitive 3α-acetyl group, thereby converting it into 3-acetoxy-urs-12-en-11-oxo- 24β-oic acid (AKBA), has been tried with various catal
