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The anti-Markovnikov rule can be illustrated using the addition of hydrogen bromide to isobutylene in the presence of benzoyl peroxide or hydrogen peroxide. The reaction of HBr with substituted alkenes was prototypical in the study of free-radical additions. Early chemists discovered that the reason for the variability in the ratio of ...
Vladimir Markovnikov was born on December 22, 1837, in Chernorechye near Nizhny Novgorod, Russian Empire (now Dzerzhinsk, Nizhny Novgorod Oblast, Russian Federation). Soon after his birth, his father retired and settled in a family estate received as a dowry from his wife's family at marriage, in the village of Ivanovo, Knyagininsky district of the Nizhny Novgorod province, where Markovnikov ...
Russian Civil War: An anti-Bolshevik government, the Committee of Members of the Constituent Assembly, was established in Samara under the protection of the Czecho-Slovak Legions 28 June A decree by the Central Executive Committee made war communism , under which all industry and food distribution was nationalized, the economic policy of the ...
In 1869, a Russian chemist named Vladimir Markovnikov demonstrated that the addition of HBr to alkenes usually but not always resulted in a specific orientation. Markovnikov's rule, which stems from these observations, states that in the addition of HBr or another hydrogen halide to an alkene, the acidic proton will add to the less substituted carbon of the double bond. [3]
Products in chemistry that follow this rule are considered Markovnikov products and those that did not are considered anti-Markovnikov products. [88] Markovnikov's rule was an early example of regioselectivity in organic synthesis and the modern understanding of it continues to be important in the chemical industry, where catalysts have been ...
With the collapse of other communist governments, and increasing street protests, the Communist Party of Czechoslovakia announced on 28 November 1989 that it would relinquish power and dismantle the single-party state. Barbed wire and other obstructions were removed from the border with West Germany and Austria in early December.
As part of the foreign policy goals in Europe, Russia initially gave guarded support to France's anti-Austrian diplomacy. A weak Franco-Russian entente soured, however, when France backed a Polish uprising against Russian rule in 1863. Russia then aligned itself more closely with Prussia by approving the unification of Germany in exchange for a ...
Throughout the history of the Soviet Union, tens of millions of people suffered political repression, which was an instrument of the state since the October Revolution.It culminated during the Stalin era, then declined, but it continued to exist during the "Khrushchev Thaw", followed by increased persecution of Soviet dissidents during the Brezhnev era, and it did not cease to exist until late ...