César R. Solorio-Alvarado

Cyclopropanation with gold(I) carbenes by retro-Buchner reaction from cycloheptatrienes.

Cationic gold(I) promotes the retro-Buchner reaction of 7-substituted 1,3,5-cycloheptatrienes, leading to gold(I) carbenes that cyclopropanate alkenes.

Gold-Catalyzed Annulation/Fragmentation: Formation of Free Gold Carbenes by Retro-Cyclopropanation

The gold(I)-catalyzed cyclization of 1-(prop-2-yn-1-yl)-2-alkenylbenzenes substituted at the benzylic position with OR groups gives 1,3-disubstituted naphthalenes with concomitant fragmentation of the alkene. One of these annulations proceeds by a retro-cyclopropanation that leads to free gold(I) carbenes.

Gold for the Generation and Control of Fluxional Barbaralyl Cations

The frog prince with his two identities pales in comparison with the shape-shifting barbaralyl cation, which exists as a mixture of 181,400 degenerate forms. Gold-catalyzed cycloisomerizations of 7-alkynyl cyclohepta-1,3,5-trienes were found to proceed via fluxional barbaralyl intermediates. The evolution of the intermediates into 1- or 2-substituted indenes could be controlled by the choice of gold complex.

Use of medicinal plants by health professionals in Mexico

ETHNOPHARMACOLOGICAL RELEVANCE The use of medicinal plants in Mexico has been documented since pre-Hispanic times. Nevertheless, the level of use of medicinal plants by health professionals in Mexico remains to be explored. AIM OF THE STUDY To evaluate the use, acceptance and prescription of medicinal plants by health professionals in 9 of the states of Mexico. MATERIALS AND METHODS Direct and indirect interviews, regarding the use and acceptance of medicinal plants, with health professionals (n=1614), including nurses, physicians, pharmacists, and odontologists from nine states in Mexico were performed from January 2015 to July 2016. The interviews were analyzed with the factor the informant consensus (FIC). RESULTS The information obtained indicated that 46% of those interviewed feel patients should not use medicinal plants as an alternative therapy. Moreover, 54% of health professionals, and 49% of the physicians have used medicinal plants as an alternative therapy for several diseases. Twenty eight percent of health professionals, and 26% of the physicians, have recommended or prescribed medicinal plants to their patients, whereas 73% of health professionals were in agreement with receiving academic information regarding the use and prescription of medicinal plants. A total of 77 plant species used for medicinal purposes, belonging to 40 botanical families were reported by the interviewed. The results of the FIC showed that the categories of diseases of the digestive system (FIC=0.901) and diseases of the respiratory system (FIC=0.898) had the greatest agreement. CONCLUSIONS This study shows that medicinal plants are used for primary health care in Mexico by health professionals.

Protecting-Group-Free Total Synthesis and Biological Evaluation of 3-Methylkealiiquinone and Structural Analogues

The modular protecting-group-free total synthesis of 3-methylkealiiquinone, an analogue of the marine alkaloid kealiiquinone, was accomplished in seven steps. A regioselectively constructed functionalized arylbenzimidazolone moiety and dimethyl squarate were used as the only two building blocks. A thermal ring expansion via 6π-conrotatory ring closure to build the quinone fragment gave rise to the desired linear analogue of the natural compound along with a nondescribed structurally attractive angular naphtho[1,2- d]imidazole regioisomer. The IC50 values for the compounds were determined on three cancer cell lines.

The antinociceptive effects of a standardized ethanol extract of the Bidens odorata Cav (Asteraceae) leaves are mediated by ATP-sensitive K+ channels

ETHNOPHARMACOLOGICAL RELEVANCE Bidens odorata Cav (Asteraceae) is used for the empirical treatment of inflammation and pain. AIM OF THE STUDY This work evaluated the in vitro and in vivo toxicity, antioxidant activity, as well as the anti-inflammatory and antinociceptive effects of an ethanol extract from Bidens odorata leaves (BOE). MATERIALS AND METHODS The in vitro toxicity of BOE (10-1000µg/ml) was evaluated with the comet assay in PBMC. The in vivo acute toxicity of BOE (500-5000mg/kg) and the effect of BOE (10-1000µg/ml) on the level of ROS in PBMC were determined. The in vivo anti-inflammatory activity of BOE was assessed using the TPA-induced ear edema in mice. The antinociceptive activities of BOE (50-200mg/kg p.o.) were assessed using the acetic acid and formalin tests. The antinociceptive mechanism of BOE was determined using naloxone and glibenclamide. RESULTS BOE lacked DNA damage, and showed low in vivo toxicity (LD50 > 5000mg/kg p.o.). BOE inhibited ROS production (IC50 = 252.13 ± 20.54µg/ml), and decreased inflammation by 36.1 ± 3.66%. In both antinociceptive test, BOE (200mg/kg) exerted activity with similar activity than the reference drugs. CONCLUSION B. odorata exerts low in vitro and in vivo toxicity, antioxidant effects, moderate in vivo anti-inflammatory activity, and antinociceptive effects mediated by ATP-sensitive K+ channels.

Total synthesis of kealiiquinone: the regio-controlled strategy for accessing its 1-methyl-4-arylbenzimidazolone core

A practical, concise and straightforward total synthesis of kealiiquinone 1, a naphtho[2,3-d]imidazole alkaloid obtained from the Micronesian marine sponge Leucetta sp. was accomplished. The squaric acid chemistry to construct the 1,4-quinoid ring and the regioselective N-methylation through a benzo[c][1,2,5]selenadiazolium heterocycle are the key features in this report. The full details of the representative approaches involving the different attempted synthetic strategies are also presented. Finally a successful total synthesis of this complex secondary metabolite is described.

Practical, mild and efficient electrophilic bromination of phenols by a new I(III)-based reagent: the PIDA–AlBr3 system

A practical electrophilic bromination procedure for phenols and phenol–ethers was developed under efficient and very mild reaction conditions. A broad scope of arenes was investigated, including the benzimidazole and carbazole core as well as analgesics such as naproxen and paracetamol. The new I(III)-based brominating reagent PhIOAcBr is operationally easy to prepare by mixing PIDA and AlBr3. Our DFT calculations suggest that this is likely the brominating active species, which is prepared in situ or isolated after centrifugation. Its stability at 4 °C after preparation was confirmed over a period of one month and no significant loss of its reactivity was observed. Additionally, the gram-scale bromination of 2-naphthol proceeds with excellent yields. Even for sterically hindered substrates, a moderately good reactivity is observed.

Self-medication practice in pregnant women from central Mexico

Self-medication during pregnancy represents a serious threat for mother and child health. The objective of this study was to evaluate the prevalence and the factors associated with self-medication among Mexican women living in the central region of Mexico. This is a descriptive interview-study of 1798 pregnant women or women who were pregnant no more than 3 years ago, when the interview was carried out. Data analysis was carried out with chi-square analysis and odds ratio. The prevalence of self-medication (allopathic drugs, medicinal plants, and other products, including vitamins, food supplements, among others) was 21.9%. The factors associated (p < 0.05) with self-medication were: higher education (college and postgraduate), smoking, and consumption of alcohol. Smoking was the strongest factor (OR: 2.536; 1.46–4.42) associated to self-medication during pregnancy, followed by consumption of alcohol (OR: 2.06; 1.38–3.08), and higher education (OR: 1.607; 1.18–2.19). Medicinal plant consumption was associated with nausea, constipation, migraine, and cold (p < 0.05), whereas he self-medication of allopathy was associated with gastritis and migraine (p < 0.05). Self-medication was influenced mainly by a relative or friend, who recommended the use of herbal medicine/allopathic medication. Two of the most common medicinal plants (arnica and ruda) here informed are reported to induce abortion or toxicity during pregnancy. The findings showed that self-medication (medicinal plants and allopathic medication) is a common practice among pregnant women from central Mexico. Adequate counselling of pregnant women by healthcare professionals about the potential risks of self-medication with herbal medicine and allopathic drugs during pregnancy is strongly warranted.