Tài liệu, ebook Khoa Học Tự Nhiên

Benzylic carbocations are resonance-stabilized, easily formed. Benzyl halides undergo SN1 reactions. Benzylic halides are 100 times more reactive than primary halides via SN2. The transition state is stabilized by a ring.

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Forms hydrazone, then heat with strong base like KOH or potassium tert-butoxide. Use a high-boiling solvent: ethylene glycol, diethylene glycol, or DMSO. A molecule of nitrogen is lost in the last steps of the reaction.

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In the presence of a strong base, primary amides react with chlorine or bromine to form shortened amines, with the loss of the carbonyl carbon atom. This reaction, called the Hofmann rearrangement, is used to synthesize primary and aryl amines.

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Ammonia and amines react with acid chlorides to give amides NaOH, pyridine, or a second equivalent of amine is used to neutralize the HCl produced to prevent protonation of the amine.

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The carbonyl carbons of acid derivatives appear at shifts around 170 to 180 ppm, slightly more shielded than the carbonyl carbons of ketones and aldehydes. The a-carbon atoms absorb around 30 to 40 ppm.

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Polycarbonates are polymers bonded to the carbonate ester linkage. The diol used to make Lexan® is a phenol called bisphenol A, a common intermediate in polyester and polyurethane synthesis.

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When attack occurs at the carbonyl group, protonation of the oxygen leads to a 1,2-addition. When attack occurs at the β-position, the oxygen atom is the fourth atom counting from the nucleophile, and the addition is called a 1,4-addition.

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Adenosine monophosphate (AMP), a regulatory hormone. Nicotinamide adenine dinucleotide (NAD), a coenzyme. Adenosine triphosphate (ATP), an energy source.

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Denaturation is defined as the disruption of the normal structure of a protein, such that it loses biological activity. Usually caused by heat or changes in pH. Usually irreversible. A cooked egg cannot be “uncooked”.

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Terpenes are classified by the number of carbons they contain in groups of ten. A monoterpene has ten carbons, two isoprene units. A sesquiterpene has 15 carbons, three isoprene units. A diterpene has 20 carbons, four isoprene units.

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