Synthesis of Conjugates of Lupane-Type Pentacyclic Triterpenoids with 2-Aminoethane- and N-Methyl-2-Aminoethanesulfonic Acids. Assessment of in vitro Toxicity

Glycoconjugation of Betulin Derivatives Using Copper-Catalyzed 1,3-Dipolar Azido-Alkyne Cycloaddition Reaction and a Preliminary Assay of Cytotoxicity of the Obtained Compounds

“…The synthesis of 28- O -chloroacetylbetulin 4 and 3,28- O,O’ -di(chloroacetyl)betulin 5 was performed by modifying the procedure described by Komissarova et al in 2017 [ 48 ]. Chloroacetic chloride was added dropwise to the betulin solution in THF, while triethylamine (Et 3 N) was replaced with N,N -diisopropylethylamine (DIPEA) and 4-(dimethylamino)pyridine (DMAP).…”

“…28- O -Chloroacetylbetulin 4 and 3,28- O,O’ -di(2-chloroacetyl)betulin 5 [ 48 ], 1,2,3,4,6-penta- O -acetyl-β-D-glucopyranose 9a , 1,2,3,4,6-penta- O -acetyl-β-D-galactopyranose 9b [ 53 ], propargyl 2,3,4,6-tetra- O -acetyl-β-D-glucopyranoside 10a [ 55 ], 2,3,4,6-tetra- O -acetyl-α-D-glucopyranosyl bromide 11a , 2,3,4,6-tetra- O -acetyl-α-D-galactopyranosyl bromide 11b [ 54 ], 2,3,4,6-tetra- O -acetyl-β-D-glucopyranosyl azide 12a , 2,3,4,6-tetra- O -acetyl-β-D-galactopyranosyl azide 12b [ 36 ], 2,3,4,6-tetra- O -acetyl- N -(β-D-glucopyranosyl)chloroacetamide 13a , 2,3,4,6-tetra- O -acetyl- N -(β-D-galacto-pyranosyl)chloroacetamide 13b , 2,3,4,6-tetra- O -acetyl- N -(β-D-glucopyranosyl)azidoacetamide 14a , and 2,3,4,6-tetra- O -acetyl- N -(β-D-galactopyranosyl)azidoacetamide 14b [ 37 ] were prepared according to the respective published procedures. All used chemicals were purchased from Sigma-Aldrich, Fluka, Avantor, and ACROS Organics and were used without purification.…”

Recent Developments in the Functionalization of Betulinic Acid and Its Natural Analogues: A Route to New Bioactive Compounds

“…BN 2 was also used as starting material to prepare ester derivatives [46,48,49]. For instance, BN derivatives bearing amino acids 77 such as alanine (Boc-L-Ala-OH), lysine [Boc-L-Lys(Boc)-OH], and three of its unnatural derivatives [2,3-diaminopropionic acid, Boc-L-Dap(Boc)-OH; 2,4-diaminobutyric acid, Boc-L-Dab(Boc)-OH; and ornithine, Boc-L-Orn(Boc)-OH] were synthesized by Drąg-Zalesińska and co-workers [48].…”