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2,3-Dichloro-5,6-dicyano-1,4-benzoquinone (or DDQ) is the chemical reagent with formula C 6 Cl 2 (CN) 2 O 2. This oxidant is useful for the dehydrogenation of alcohols, [3] phenols, [4] and steroid ketones. [5] DDQ decomposes in water, but is stable in aqueous mineral acid. [6]
The use of protective groups is pervasive but not without criticism. [103] In practical terms their use adds two steps (protection-deprotection sequence) to a synthesis, either or both of which can dramatically lower chemical yield. Crucially, added complexity impedes the use of synthetic total synthesis in drug discovery.
p-Methoxybenzyl (PMB) is used as a protecting group for alcohols in organic synthesis (4-Methoxybenzylthiol is used to protect thiols). The p -methoxybenzyl group Strong base such as powdered potassium hydroxide or sodium hydride and p -methoxybenzyl halide (chloride or bromide) [ 14 ] [ 15 ]
It is also a good test for the successful deprotection of a secondary amine. Secondary amines react with chloranil to give a brown/red/orange derivative, the colour depending on the amine. In these reactions, the amine displaces chloride from the ring of the quinone.
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Victor Mendoza, the president of a farming co-op near the sprawling Yanacocha gold mine in northern Peru, with his 10-year-old son. The mine, built two decades ago with the financial backing of the International Finance Corp., the private-lending arm of the World Bank, is deeply unpopular in this region.
Financial risk management is the practice of protecting economic value in a firm by managing exposure to financial risk - principally credit risk and market risk, with more specific variants as listed aside - as well as some aspects of operational risk.
PHOTO: Rep. Tulsi Gabbard during the State of the Union address before members of Congress in the House chamber of the Capitol, Feb. 5, 2019. (Melina Mara/The Washington Post via Getty Images)