Mild and Chemoselective Deacetylation Method Using a Catalytic Amount of Acetyl Chloride in Methanol.

Abstract

Deprotection O 0345 Mild and Chemoselective Deacetylation Method Using a Catalytic Amount of Acetyl Chloride in Methanol. -The procedure allows the efficient removal of acetyl groups in the presence of other acid-sensitive protecting groups. -(YEOM, C.-E.; LEE, S. Y.; KIM, Y. J.; KIM*, B. M.; Synlett 2005, 10, 1527-1530; Sch. Chem., Seoul Natl. Univ., Seoul 151-747, S. Korea; Eng.) -Mais 47-055

Structure and Activity of the Camellia oleifera Sapogenin Derivatives on Growth and Biofilm Inhibition of Staphylococcus aureus and Escherichia coli

“…Purified sapogenin is an amorphous powder with a purity of 91.62% by HP 1100 HPLC (Agilent, Santa Clara, CA, U.S.A.) in the following operating conditions: column, Hypersil ODS (250 × 4.6 mm, 5 μm); flow phase, methanol/water (80:20); injection volume, 10 μL; flow rate, 1 mL/min; temperature, 25 °C; and wavelength, 218 nm. IR spectra and 1 H and 13 C NMR data showed that it had a sapogenin structure with formula C 30 H 48 O 5 , which is consistent with our former literature. 9 A total of 19 derivatives of sapogenin were synthesized with different substituent groups in the C 28 position, and their yields are listed in Table 1.…”

“…9 A total of 19 derivatives of sapogenin were synthesized with different substituent groups in the C 28 position, and their yields are listed in Table 1. All products were measured by IR, mass spectrometry (MS), and 1 H and 13 C NMR to confirm their structures.…”

“…Third, formic acid was added to remove the tritylmethyl group, so that the C 28 hydroxyl group is exposed to react with a series of acylation reagents using DMAP as a catalyst. 12 At last, the acetyl protecting groups of the secondary hydroxyl group were removed by acyl chloride, 13 and C. oleifera sapogenin derivatives were collected from silica gel column chromatography with elution of petroleum ether/ethyl acetate/acetic acid at a volume ratio of 20:10:1. The detailed procedures for intermediates 1a−3a and Camellia sapogenin derivatives are available in the Supporting Information.…”

“…Mass spectra were recorded on a Bruker maXis mass spectrometer with electrospray ionization (ESI) (Bruker, Germany) in m/z of the cation model scanning from 150 to 1200 for 60 min. Nuclear magnetic resonance (NMR) spectra were determined on 400 MHz AM NMR (Bruker, Switzerland) in C 2 D 6 SO operating at 101 MHz for 13 C NMR and 400 MHz for 1 H NMR.…”

Concise Syntheses of Trifluoromethylated Cyclic and Acyclic Analogues of cADPR

“…Compound 16 was successfully converted to 17 by the reaction with S,S -diphenylphosphorodithioate (PSS) [ 20 ] in the presence of triisopropylbenzenesulfonyl chloride (TPSCl) and tetrazole in pyridine, in a yield of 79%. Considering the instability of phenylthio group under basic conditions [ 21 ], acetyl chloride in methanol (AcCl/MeOH) [ 22 ] was applied to the deacetylation of 17 . When 1.2 equivalent of AcCl was utilized, compound 17 was successfully converted to 18 .…”