1181-44-8Relevant articles and documents
Hard Acid and Soft Nucleophile System. 2.Demethylation of Methyl Ethers of Alcohol and Phenol with an Aluminum Halide-Thiol System
Node, Manabu,Nishide, Kiyoharu,Fuji, Kaoru,Fujita, Eiichi
, p. 4275 - 4277 (1980)
Aliphatic and aromatic methyl ethers have been easily cleaved on treatment with a hard acid, aluminum halide, and a soft nucleophile, EtSH, to give parent alcohols and phenols, respectively.With compounds possessing both aliphatic and aromatic methyl ether groups, simultaneous demethylation of both types of ethers occurred.The ethereal carbon-oxygen bond in compounds possessing both ether and ester groups was selectively cleaved under mild conditions by using dichloromethane as a cosolvent.Acetoxyl and N-acetyl groups were shown to be stable to this reagent system, except for easy hydrolysis of aromatic acetoxyl groups under conditions of workup after the reaction.
Leveraging of rifampicin-dosed cynomolgus monkeys to identify bile acid 3-O-sulfate conjugates as potential novel biomarkers for organic anion-transporting polypeptidess
Thakare, Rhishikesh,Gao, Hongying,Kosa, Rachel E.,Bi, Yi-An,Varma, Manthena V. S.,Cerny, Matthew A.,Sharma, Raman,Kuhn, Max,Huang, Bingshou,Liu, Yiping,Yu, Aijia,Walker, Gregory S.,Niosi, Mark,Tremaine, Larry,Alnouti, Yazen,Rodrigues, A. David
, p. 721 - 733 (2017)
In the search for novel bile acid (BA) biomarkers of liver organic anion-transporting polypeptides (OATPs), cynomolgus monkeys received oral rifampicin (RIF) at four dose levels (1, 3, 10, and 30 mg/kg) that generated plasma-free Cmax values (0.06, 0.66, 2.57, and 7.79 μM, respectively) spanning the reported in vitro IC50 values for OATP1B1 and OATP1B3 (≤1.7 μM). As expected, the area under the plasma concentration-time curve (AUC) of an OATP probe drug (i.v.2H4-pitavastatin, 0.2 mg/kg) was increased 1.2-, 2.4-, 3.8-, and 4.5-fold, respectively. Plasma of RIF-dosed cynomolgus monkeys was subjected to a liquid chromatography-tandem mass spectrometry method that supported the analysis of 30 different BAs. Monkey urine was profiled, and we also determined that the impact of RIF on BA renal clearance was minimal. Although sulfated BAs comprised only 1% of the plasma BA pool, a robust RIF dose response (maximal ?50-fold increase in plasma AUC) was observed for the sulfates of five BAs [glycodeoxycholate (GDCA-S), glycochenodeoxycholate (GCDCA-S), taurochenodeoxycholate, deoxycholate (DCA-S), and taurodeoxycholate (TDCA-S)]. In vitro, RIF (≤100 μM) did not inhibit cynomolgus monkey liver cytosol-catalyzed BA sulfation and cynomolgus monkey hepatocyte-mediated uptake of representative sulfated BAs (GDCA-S, GCDCA-S, DCA-S, and TDCA-S) was sodium-independent and inhibited (≥70%) by RIF (5 μM); uptake of taurocholic acid was sensitive to sodium removal (74% decrease) and relatively refractory to RIF (≤21% inhibition). We concluded that sulfated BAs may serve as sensitive biomarkers of cynomolgus monkey OATPs and that exploration of their utility as circulating human OATP biomarkers is warranted.
Partial synthesis of a marine secosterol from Gersemia fruticosa: Preparation of the intermediate precursor 3β,6α-diacetoxy-24-methyl-12-oxo-5α-chol-9,11-en-24-oate
Kuhl, Alexander,Kreiser, Wolfgang
, p. 1145 - 1148 (1998)
The conversion of desoxycholic acid (2) into the title compound 14 by 13 respectively 17 steps is described herein, including stereoselective construction of C-3 and C-6 hydroxy moieties and introduction of a Δ9,11 double bond by dehydrogenation. 14 is believed to serve as a putative precursor for the synthesis of secosterol 1, isolated from the soft coral Gersemia fruticosa.
Synthesis, aggregation behavior and cholesterol solubilization studies of 16-epi-pythocholic acid (3α,12α,16β-trihydroxy-5β-cholan-24-oic acid)
Nonappa,Maitra, Uday
, p. 506 - 512 (2010)
Synthesis, aggregation behavior and in vitro cholesterol solubilization studies of 16-epi-pythocholic acid (3α,12α,16β-trihydroxy-5β-cholan-24-oic acid, EPCA) are reported. The synthesis of this unnatural epimer of pythocholic acid (3α,12α,16α-trihydroxy-5β-cholan-24-oic acid, PCA) involves a series of simple and selective chemical transformations with an overall yield of 21% starting from readily available cholic acid (CA). The critical micellar concentration (CMC) of 16-epi-pythocholate in aqueous media was determined using pyrene as a fluorescent probe. In vitro cholesterol solubilization ability was evaluated using anhydrous cholesterol and results were compared with those of other natural di- and trihydroxy bile acids. These studies showed that 16-epi-pythocholic acid (16β-hydroxy-deoxycholic acid) behaves similar to cholic acid (CA) and avicholic acid (3α,7α,16α-trihydroxy-5β-cholan-24-oic acid, ACA) in its aggregation behavior and cholesterol dissolution properties.
Synthesis of task-specific imidazolium ionic liquid as an efficient catalyst in acetylation of alcohols, phenols, and amines
Chaubey, Snehkrishn A.,Mishra, Roli
, p. 3259 - 3268 (2020/04/17)
Herein, we report the synthesis of task-specific amino-functionalized imidazolium ionic liquid, acetate1-(2-tert-butoxycarbonylamino-ethyl)-3-methyl-3H-imidazol-1-ium; (Boc-NH-EMIM.OAc), as an efficient catalyst for the acetylation of alcohols, phenols, and amines in the presence of acetic anhydride (acetylating reagent). Remarkably, acetic anhydride in the presence of 10?molpercent of catalyst (Boc-NH-EMIM.OAc) under solvent-free conditions showed excellent acetylation activity in shorter duration of time. On the basis of this, a general procedure for acetylation of alcohols, phenols, and amines has been developed. The ionic liquid (Boc-NH-EMIM.OAc) can be readily recovered and reused successfully up to four consecutive cycles without any significant loss of its catalytic activity. We have been able to show that this acetylating method has many advantages. It gives high yields, takes shorter time, and develops the possibility of benign environmental-friendly process.
Protection of COOH and OH groups in acid, base and salt free reactions
Zhu, Xiaotao,Qian, Bo,Wei, Rongbiao,Huang, Jian-Dong,Bao, Hongli
supporting information, p. 1444 - 1447 (2018/04/12)
We report an iron-catalyzed general functional group protection method with inexpensive reagents. This environmentally benign process does not use acids or bases, and does not produce waste products. Further purification beyond filtration and evaporation is, in most cases, unnecessary. Free COOH and OH groups can be protected in a one-pot reaction.
