1. O-Methylation of carboxylic acids with streptozotocin
Li-Yan Zeng, Yang Liu, Jiakun Han, Jinhong Chen, Shuwen Liu, Baomin Xi Org Biomol Chem. 2022 Jul 6;20(26):5230-5233. doi: 10.1039/d2ob00578f.
The clinically used DNA-alkylating drug streptozotocin (STZ) was investigated using a simple work-up as an O-methylating agent to transform various carboxylic acids, sulfonic acids and phosphorous acids into corresponding methyl esters, and did so with yields of up to 97% in 4 h at room temperature. Good substrate tolerance was observed, and benefited from the mild conditions and compatibility of the reaction with water.
2. Synthesis and cytotoxic activity of 4-O-β-D-galactopyranosyl derivatives of phenolic acids esters
Nader Al Bujuq, Sharif Arar, Raida Khalil Nat Prod Res. 2018 Nov;32(22):2663-2669. doi: 10.1080/14786419.2017.1375927. Epub 2017 Sep 18.
The glycosylation of naturally occurring phenolic acids has a significant impact on their solubility, stability and physiochemical properties. D-Galactose residue was found to form a part of glycoconjugates in several tissues and involved in a variety of physiological process. To the best of our knowledge, we have noticed a little information about the glycosylation of the phenolic acids with galactose residue. In this work, we describe the glycosylation of methyl vanillate and methyl ferulate with peracetylated-β-D-galactopyranose in the presence of BF3·OEt2. The coupling reaction yielded efficiently and selectively only the acetylated β-D-galactopyranosides 3 and 6. Removal of the acetyl groups using sodium methoxide afforded the corresponding β-D-galactopyranosides 4 and 7 in good yields. Anticancer activity in vitro was evaluated against two human cancer cell lines (MCF-7 breast cancer cell lines and PC-3 prostate cancer cell lines). β-D-galactopyranosides 4 and 7 demonstrated improved cytotoxic activity compared to the parental esters.
3. Acridinium Ester Chemiluminescence: Methyl Substitution on the Acridine Moiety
Manabu Nakazono, Shinkoh Nanbu, Takeyuki Akita, Kenji Hamase J Oleo Sci. 2021;70(11):1677-1684. doi: 10.5650/jos.ess21186.
Methyl groups were introduced on the acridine moiety in chemiluminescent acridinium esters that have electron-withdrawing groups (trifluoromethyl, cyano, nitro, ethoxycarbonyl) at the 4-position on the phenyl ester. The introduction of methyl groups at the 2-, 2,7-, and 2,3,6,7-positions on the acridine moiety shifted the optimal pH that gave relatively strong chemiluminescence intensity from neutral conditions to alkaline conditions. 4-(Ethoxycarbonyl)phenyl 2,3,6,7,10-pentamethyl-10λ4-acridine-9-carboxylate, trifluoromethanesulfonate salt showed long-lasting chemiluminescence under alkaline conditions. Acridinium esters to determine hydrogen peroxide concentration at pH 7-10 were newly developed.
