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A new acetophenone glycoside, affinoside, was isolated from the aerial parts of Exacum affine and its structure was determined as 2-O-primeverosylpaenol. The known glucosides, gentiopicroside, 2'-O-E/Z-p-coumaroylloganin and glucopaeonol, were also identified.
We have identified and synthesized a series of aryl-tetrazoyl acetophenones as positive allosteric potentiators of the metabotropic glutamate receptor 2. Structure activity relationship studies directed toward improving the potency and level of potentiation led to the discovery of 22 (EC(50)=93nM, 128% potentiation).
We have identified and synthesized a series of 4-thiopyridyl acetophenones as positive allosteric potentiators of the metabotropic glutamate receptor 2. Structure-activity relationship studies directed toward replacement of the tetrazole in the initial lead led to the discovery of 16 (EC(50)=340 nM), which showed improved brain penetration over the initial lead.
Protein tyrosine phosphatase 1B (PTP1B) is an enzyme that plays a critical role in down-regulating insulin signaling through dephosphorylation of the insulin receptor. Studies have shown that PTP1B knock-out mice showed increased insulin sensitivity in muscle and liver as well as resistance to obesity. A series of functionalized acetophenones were synthesized and evaluated for their PTP1B inhibitory activity. Some of the screened compounds displayed good inhibitory activity.
Three acetophenone C-glycosides; 2,4,6-trihydroxyacetophenone 3-C-beta-(2'-O-p-hydroxybenzoyl)-glucopyranoside, 2,4,6-trihydroxyacetophenone 3-C-beta-(2'-O-E-coumaroyl)-glucopyranoside, 2,4,6-trihydroxyacetophenone 3-C-beta-(2'-O-E-cinnamoyl)-glucopyranoside, and two resveratrol O-glycosides; piceid 2'-O-p-hydroxybenzoate and, piceid 2'-O-E-ferulate, together with three known compounds were isolated from the acetone soluble part of stem of Upuna borneensis (Dipterocarpaceae). The structures of isolates were determined by spectral analysis including extensive 2D-NMR spectral analyses.
The isotropic component of Raman band for C=O stretching mode of acetophenone in solution was analyzed by estimating the correlation coefficient with reference to Lorentzian lineshape. In the intermediate region of solute/solvent concentration there is a sharp decrease in the correlation coefficient and there appears to be a transition from non-Lorentzian to Lorentzian lineshape. The vibrational relaxation rates have been estimated from the isotropic component of Raman band in different solvents. The rate is shown to be dependent on several macroscopic as well as microscopic properties of the solute-solvent system and intermolecular interactions. The hydrodynamic and dispersion forces appear to play a major role in determining the vibrational relaxation rate and the broadening of the bands.
The RM values of naphthols obtained in a chromatographic system where the stationary phase consisted of a silica gel G layer impregnated with silicone oil are much more closely related to the log P values in an octanol-water system than the RM values determined on polyamide layers. Similarly, the RM values of a series of acetophenones in the silicone system are closely related to their log P values. The equations describing the structure-activity relationship indicate the importance of lipophilic character and halogen substitution in determining the hemolytic activity and the acute toxicity of compounds.
A naturally occurring flavonoid, myrigalone B (2',6' -dihydroxy-4'-methoxy-3',5'-dimethyl-dihydrochal-cone) is an effective antioxidant and scavenger of the diphenylpicrylhydrazyl radical, while the closely related angoletin (2',4'-dihydroxy-6'-methoxy-3',5'-dimethyl-dihydrochalcone) is inactive. From NMR spectra, it appears that myrigalone B has a time-averaged conformation in which the substituted aromatic ring is orthogonal to the carbonyl group, while angoletin is coplanar. By donating a phenolic hydrogen in radical scavenging, myrigalone B will lose its symmetrical structure and may thereby change to a coplanar conformation forming a strong intramolecular hydrogen bond between the remaining phenolic hydrogen and the carbonyl group. The energy gain entailed would then appear to be a driving force for the radical scavenging by myrigalone B. Angoletin, being coplanar, lacks this driving force. To verify this hypothesis, the conformation and radical scavenging activity of a series of phenolic acetophenones were studied. All substances that had an orthogonal conformation and could form intramolecular hydrogen bonds by loss of a phenolic hydrogen were DPPH scavengers, while compounds lacking these properties were inactive. From this, we propose that formation of intramolecular hydrogen bonds may lead to radical scavenging activity.
Substituted acetophenones react with N-bromosuccinimide (NBS) and p-toluenesulfonic acid (p-TsOH) in the presence of ultrasound in methanol at 35 +/- 2 degrees C to give alpha-bromoacetophenones in high yield. In the absence of ultrasound the reaction takes place at the boiling point of methanol (65 degrees C) and takes longer time. The reaction does not take place in the absence of p-TsOH thermally or sonically. However the reaction is possible under photochemical conditions in the absence of p-TsOH. The best solvent for the reaction was found to be methanol.
A method for solid phase extraction of trace metals, namely, Cd, Cu, and Ni, using Amberlite XAD-2 functionalized with a new chelating ligand, 2-hydroxy-acetophenone-3-thiosemicarbazone (Amberlite XAD-2-HAPTSC), has been developed. The optimum experimental conditions for the quantitative sorption of three metals, pH, effect of flow rate, concentration of eluent, sorption capacity, kinetics of sorption, and the effect of diverse ions on the sorption of analytes have been investigated. The chelating resin could be reused for more than 20 cycles of sorption-desorption without any significant change (<1.5%). The accuracy of the proposed procedure was evaluated by standard reference materials. The proposed method was applied for the determination of trace metal ions in leafy vegetable samples collected from different sources and medicinal plant leaves.
Four acetophenone glycosides were isolated from the butanol-soluble fraction of thyme extracts. Their structures were determined by spectral methods (MS, NMR, and 2D-NMR). Among them, two new compounds, 4-hydroxyacetophenone 4-O-[5-O-(3, 5-dimethoxy-4-hydroxybenzoyl)-beta-D-apiofuranosyl]-(1-->2)-beta-D -gl ucopyranoside (1) and 4-hydroxyacetophenone 4-O-[5-O-(4-hydroxybenzoyl)-beta-D-apiofuranosyl]-(1-->2)-beta-D-+ ++gluc opyranoside (2), were determined. Compound 1 showed weak cytotoxicity, inhibiting DNA synthesis of human leukemia cells.
2-(5-Nitro-2-imidazolylmethylene)-1-indanones, -1-tetralones, and -acetophenones substituted by aminoalkoxy groups and related compounds (41-69, table ii) were synthesized and their antimicrobial activities were evaluated (table iii). Some of these compounds (e.g. 47, 52, and 59) suprisingly exhibited a broad antibacterial spectrum including Proteus species and Pseudomonas aeruginosa. Extraordinary antitrichomonal activities could also be observed in vitro (MIC of compound 59, 0.0004 pg/ml) and six of the title compounds (48, 49, 52, 58, 64, 66) displayed in vivo activity in mice against Trichomonas vaginalis comparable to that of metronidazole (70).
Analogues of the leukotriene D4/E4 receptor antagonist LY171883 (1a) were synthesized in which the tetrazole was linked to the hydroxyacetophenone moiety by an all-methylene carbon chain. A key step in the synthesis involved a Wittig olefin-forming reaction between 3-methoxy-2-propylbenzaldehyde and the ylide derived from (4-carboxybutyl)triphenylphosphonium bromide to form the desired carbon chain. A regioselective Fries rearrangement was employed to form the o-hydroxyacetophenone. Compounds in which the tetrazole was separated from the acetophenone by four and five methylene groups were compared to the corresponding derivatives in which an oxygen atom linked the tetrazole chain to the aromatic ring for their ability to antagonize LTD4- or LTE4-induced contractions of the isolated guinea pig ileum. When compared to 1a, the "carba" analogue, 7a, showed nearly identical LTD4 antagonist activity. The LTE4 antagonist activity for these two compounds was also identical. In the shorter chain series, the "carba" analogue, 7b, showed enhanced LTD4 antagonist activity and approximately 10-fold greater LTE4 antagonist activity. These results suggest that the oxygen atom para to the acetyl group of 1a and 1b is not of major importance for association with the LTD4 or LTE4 receptor sites in the guinea pig ileum.
Herein we disclose the discovery of a new class of positive allosteric potentiators of the metabotropic glutamate receptor 2 (mGlu2), phenyl-tetrazolyl acetophenones, e.g. 1-(2-hydroxy-3-propyl-4-[4-[4-(2H-tetrazol-5-yl)phenoxy]butoxy]phenyl) ethanone (4). These potentiators were shown to have no effect in the absence of glutamate as well as no effect at mGlu3 or the other mGlu receptors. The compounds were also evaluated in rodent models with potential relevance for schizophrenia, and 4 was shown to have activity in the inhibition of ketamine-induced norepinephrine release and ketamine-induced hyperactivity. This represents the first example of the efficacy of mGlu2 receptor potentiators in these models.
Dipole parallel-alignment of organic molecular crystals of azines has been achieved with a design that was based on the hypothesis that the azine bridge is a conjugation stopper. This hypothesis has now been tested in detail, and (1)H and (13)C NMR spectroscopic data of symmetric and asymmetric acetophenone azines are presented in support of this design concept. Previous structural, ab initio, and electrochemical studies have shown that the azine bridge largely inhibits through-conjugation in molecules with the general structure DPhC(Me) [double bond] N [bond] N [double bond] C(Me)PhA, where D is a donor group and A is an acceptor group. NMR spectroscopy is an excellent tool to probe the degree of conjugation through the azine bridge. The NMR results reported here for nine symmetrical and 18 asymmetrical azines show in a compelling fashion that the hypothesis holds. Varying the donor group does not change the chemical shifts of the aromatic hydrogen and carbon atoms on the acceptor-substituted phenyl ring. Likewise, varying the acceptor group does not change the chemical shifts of the atoms in the donor-substituted phenyl ring.
Three new acetophenone glucosides (4-6), three known aglycons (1-3), and a benzo-gamma-pyrone glucoside (7) were isolated from the CH(2)Cl(2), EtOAc, and BuOH extracts from the aerial parts of Helichrysum italicum. All the compounds tested showed antiinflammatory activity in a 12-O-tetradecanoylphorbol 13-acetate (TPA)-induced mouse ear edema test, and the ID(50) value of compound 2, the most active compound, was determined.
Chemical investigation on the stem and root bark of Acronychia pedunculata has resulted in the isolation of five new acetophenones, namely, acronyculatins A (1), B (2), C (3), D (4), and E (5). The structures of these metabolites were established on the basis of their 1D and 2D NMR spectroscopic and mass spectrometric data and by CD spectroscopy. The antioxidant and antityrosinase activities of these five metabolites and acrovestone (6) were evaluated. Among these compounds, 6 showed marginal antioxidant and antityrosinase activities.
A series of substituted acetophenones, paraformaldehyde, and symmetrical dialkylamines were used in microwave enhanced Mannich reactions. Appropriate reaction conditions in terms of choice of solvent, reaction temperature, and reaction time were studied to allow a fast and reproducible production of Mannich bases. Both small (2 mmol) and large scale reactions (40 mmol) were performed successfully, providing a series of substituted Mannich bases in moderate to high yields and high purity.