RESUMO
With dimethyl sulfoxide (DMSO) as the methylthio source, a KF-catalyzed strategy was employed for the direct thiomethylation of carboxylic acids with DMSO for the preparation of methyl thioesters. In this process, a wide range of methyl thioesters were obtained in moderate to excellent yields. This novel strategy features the first use of DMSO as a methylthiolating agent for the construction of methyl thioesters, transition metal-free conditions, inexpensive reagents, easy workup, broad substrate scope and sustainability. Additionally, this procedure can be readily scaled up to a gram scale.
RESUMO
Cinnamigones A-C, three undescribed highly oxidized guaiane-type sesquiterpenes were isolated from the fruits of Cinnamomum migao. Cinnamigone A (1), structurally artemisinin-like, is a natural 1,2,4-trioxane caged endoperoxide with an unprecedented tetracyclic 6/6/7/5 ring system. Compounds 2-3 are classic guaiane sesquiterpene featuring different epoxy units. Guaiol (4) is considered to be the precursor of 1-3 in the biosynthesis pathway hypothesis. The planar structures and configurations of cinnamigones A-C were elucidated by spectral analysis, HRESIMS, X-ray crystallography and ECD calculations. Evaluation of the neuroprotective activity of 1-3 on N-methyl-á´ aspartate (NMDA) toxicity was demonstrated that compounds 1-2 exhibited moderate neuroprotective activity against NMDA-induced neurotoxicity.
Assuntos
Cinnamomum , Sesquiterpenos , Estrutura Molecular , N-Metilaspartato , Sesquiterpenos/farmacologia , Sesquiterpenos/química , Sesquiterpenos de Guaiano/farmacologiaRESUMO
Scholars and policy makers have for centuries constructed and used developmental hierarchies to characterize different countries. The hypotheses motivating this paper are that such social constructions have been circulated internationally, are constructed similarly in various countries, and follow the social constructions of elite international organizations, such as the United Nations. This paper uses data from 15 surveys in 13 diverse countries to study how developmental hierarchies are understood in everyday life. Our research shows that most people have constructions of developmental hierarchies that are similar across countries and are similar to the developmental hierarchies constructed by the United Nations. These findings suggest that developmental hierarchies are widely understood around the world and are widely available to ordinary people as they make decisions about many aspects of life.
RESUMO
OBJECTIVES: Severity and timing are key aspects of disability experience for individuals. They also generate a population's disability structure (prevalence, counts, patterns). We study links among severity, duration, and structure for community-dwelling adults in the US. METHODS: The data source is the National Health Interview Survey Disability Supplement. Disabilities in personal care (ADL), household management (IADL), and physical functions (PLIM) are analyzed. RESULTS: Many combinations of disabilities are possible, but just a few are frequent; the top-10 patterns cover 70% of ADL, 89% of IADL, and 47% of PLIM disabled adults. Hierarchical patterns are common for ADLs and IADLs. People with many disabilities also have more-severe ones, and their disabilities often started at the same time. CONCLUSIONS: Disability structure reflects severity and timing of specific disabilities, sometimes strongly, and other times weakly due to exit processes from the community. Assumptions that disability occurs in "hard" tasks first and "easy" ones last, and that hard-and-early connotes mild disability whereas easy-and-late connotes severe, need direct empirical testing.