5044

The Strecker synthesis is a method for preparing amino acids from aldehydes by using ammonia and hydrogen cyanide:

Propose a mechanism for the formation of the intermediate product, the a‑aminonitrile.

5090

Betaine, C₅H₁₁O₂N, occurs in beet sugar molasses. It is a water soluble solid that melts with decomposition at 300°. It is unaffected by base but reacts with hydrochloric acid to form a crystalline product, C₅H₁₂O₂NCl. Betaine can be prepared in either of two ways: by treatment of glycine with methyl iodide, or by treatment of chloroacetic acid with trimethylamine. Draw a structure for betaine that accounts for its properties.

5093

Starting with diethylmalonate and other organic and inorganic substances, show how the amino acid valine can be synthesized.

5121

Argaritine (C₁₂H₁₇N₃O₄) is a reducing substance which can be isolated from mushrooms. It gives a positive test for a-amino acid (ninhydrin), and can be hydrolyzed enzymatically to A (C₇H₁₀N₂O) and B (C₅H₉NO₄). A reacts rapidly with most ketones to give a solid derivative. It can also be oxidized with selenous acid to an aryl diazonium salt, which can be hydrolyzed to a phenol C (C₇H₈O₂). Further oxidation of C produces an acid which on nitration forms one and only one mononitro derivative. B, which is optically active, can be synthesized in high yield as a racemate by the hydrolysis of the intermediate formed by the action of ammonium cyanide on succinic semialdehyde (HO₂CCH₂CH₂CHO). Identify the lettered compounds and write equations for the reactions described above.

5251

State whether the following statements or equations are true or false. If any part of a statement is not true or any part of an equation is incorrect, then the item is false.

(a)

(b) compound below is chiral and capable of being resolved

(c) phenanthrene under goes addition reactions across the 9,10 position because that is sterically the most accessible position

Phenanthrene

(d) the reaction below is an example of the Kiliani-Fischer method of synthesis of amino acids

5379

Starting with diethylmalonate and other organic and inorganic substances, show how the amino acid alanine can be synthesized.