46 research outputs found
The Victimization of the African Girl Child: Primary Schools as Unsafe Spaces for Girls in Cameroon
Violence against girls in and out of school settings is a problem that is on the rise in countries of sub-Sharan Africa. In Cameroon today, the abuse of girls has progressed into the realm of primary education affecting prepubescent girls, making schools unsafe spaces for girls and thereby, hindering them from accessing and furthering their education, basic rights and agency. A study on the victimization of primary school girls in Malawi funded by the United Nations found that girls are subject to several forms of violence as a result of their gender and that this disrupts their access to basic education (Bisika, Ntata and Konyani 2009). This study also established that there are various forms of violence against girls; prominent among these are beatings, sexual assault and rape by both boys and teachers, and discriminatory classroom practices that favor boys (ibid). Using this study as a basis for comparison with the situation in my country Cameroon, I argue that many girl children in Cameroon also suffer similar abuse today, and that the UN Millennium Development Goals of 2000 that aimed at ending gender-based violence, extreme poverty, and promoting primary education for girls in its Member States by 2015, which was the basis the Malawian study was carried out, have not been realized. Focusing on Cameroon and using a qualita-tive approach of data analysis, I use secondary data analysis that build upon Girls Studies, Gender-Based Violence and Third World/African feminisms. These theoretical frameworks help situate the African girl child in a global space that is unfavorable to her political and personal advancement. In order to examine the situation of the girl child in Cameroon, I make use of semi-structured interviews with grassroots advocates for girl child empowerment in Cameroon. This study therefore aims to understand whether Cameroonian girls ex-perience the same kinds of abuse as girls of other African countries; whether abuse inhibits girls’ access to primary education, and how grassroots advocates are involved in preventing or responding to abuse of girls
A chemical probe based on the PreQ1 metabolite enables transcriptome-wide mapping of binding sites
The role of metabolite-responsive riboswitches in regulating gene expression in bacteria is well known and makes them useful systems for the study of RNA-small molecule interactions. Here, we study the PreQ1 riboswitch system, assessing sixteen diverse PreQ1-derived probes for their ability to selectively modify the class-I PreQ1 riboswitch aptamer covalently. For the most active probe (11), a diazirine-based photocrosslinking analog of PreQ1, X-ray crystallography and gel-based competition assays demonstrated the mode of binding of the ligand to the aptamer, and functional assays demonstrated that the probe retains activity against the full riboswitch. Transcriptome-wide mapping using Chem-CLIP revealed a highly selective interaction between the bacterial aptamer and the probe. In addition, a small number of RNA targets in endogenous human transcripts were found to bind specifically to 11, providing evidence for candidate PreQ1 aptamers in human RNA. This work demonstrates a stark influence of linker chemistry and structure on the ability of molecules to crosslink RNA, reveals that the PreQ1 aptamer/ligand pair are broadly useful for chemical biology applications, and provides insights into how PreQ1, which is similar in structure to guanine, interacts with human RNAs
DIRECTED sp3 C–C AND C–H BOND CLEAVAGE FOR RADICAL BASED FUNCTIONALIZATIONS
Fluorine-containing organic molecules have become an indispensable in medicinal chemistry, agrochemistry, materials science, and biology. Despite all these applications in many fields of chemistry, there are limited ways to access most fluorinated molecules, especially organic molecules containing aliphatic fluorides. Ideally, one would like to access aliphatic fluorides through direct functionalization of sp3 C–H bonds (via radical based routes), and this would open limitless possibilities to synthesize a variety of fluorinated molecules. Recently, our laboratory and others accomplished a notable improvement in controlling the reactivity of aliphatic C–H bonds towards radical based fluorinations, but had only demonstrated selective sp3 C–H bond fluorination on highly symmetric substrates or those containing more activated benzylic C–H bonds. As a next step in progress, there was a great need to direct radical fluorination in complex natural products. We envisioned two approaches to accomplish this task through directed sp3 C–C bond cleavage or C–H bond functionalization. Accordingly, herein, directed-fluorination methods, and advances in selectivity in functionalizing peptides, terpenoids, and other complex organic molecules using either guided C–C cleavage or carbonyl groups to target unactivated C–H bonds are discussed. These strategies have helped radical based fluorination reactions become a valuable synthetic approach to functionalize complex natural products through late-stage fluorination. Additionally, we briefly explored the use of cyclopropanol derived radicals to couple with electron deficient heteroaromatic rings
Tandem C-C Bond Cleavage of Cyclopropanols and Oxidative Aromatization by Manganese(IV) Oxide in a Direct C-H to C-C Functionalization of Heteroaromatics
Abstract: We report a direct C-H to C-C bond functionalization of electron-deficient heteroaromatics enabled by mild C-C bond cleavage of cyclopropanols as a new route to β-aryl carbonyl-containing products. Additionally, as an alternative to using a "catalyst" that requires an excess amount of a sacrificial oxidant for regeneration and/or oxidative aromatization, this paper features manganese(IV) oxide as an inexpensive "dual role" reagent -effecting both C-C bond cleavage and ultimate rearomatization. Under the specified conditions, a variety o
Sensitized Aliphatic Fluorination Directed by Terpenoidal Enones: A “Visible Light” Approach
In
our continued effort to address the challenges of selective
sp<sup>3</sup> C–H fluorination on complex molecules, we report
a sensitized aliphatic fluorination directed by terpenoidal enones
using catalytic benzil and visible light (white LEDs). This sensitized
approach is mild, simple to set up, and an economical alternative
to our previous protocol based on direct excitation using UV light
in a specialized apparatus. Additionally, the amenability of this
protocol to photochemical flow conditions and preliminary evidence
for electron-transfer processes are highlighted
Multiple Enone-Directed Reactivity Modes Lead to the Selective Photochemical Fluorination of Polycyclic Terpenoid Derivatives
In the realm of aliphatic fluorination,
the problem of reactivity
has been very successfully addressed in recent years. In contrast,
the associated problem of selectivity, that is, directing fluorination
to specific sites in complex molecules, remains a great, fundamental
challenge. In this report, we show that the enone functional group,
upon photoexcitation, provides a solution. Based solely on orientation
of the oxygen atom, site-selective photochemical fluorination is achieved
on steroids and bioactive polycycles with up to 65 different sp<sup>3</sup> CH bonds. We have also found that γ-, β-,
homoallylic, and allylic fluorination are all possible and predictable
through the theoretical modes reported herein. Lastly, we present
a preliminary mechanistic hypothesis characterized by intramolecular
hydrogen atom transfer, radical fluorination, and ultimate restoration
of the enone. In all, these results provide a leap forward in the
design of selective fluorination of complex substrates that should
be relevant to drug discovery, where fluorine plays a prominent role