A-Aminocarboxylic acids amides

The four component condensation (Ugi reaction) " converts a mixture of substituted amine, isonitrile, aldehyde (or ketone) and carboxylic acid (Scheme 6) to a-acylaminocarboxylic acid amides (pathway a), to diacylamines (pathway b) and to a-aminocarboxylic acid amides (pathway... 

N-Protected a-aminocarboxylic acid amides. A soln. of N-(4-methoxybenzyloxycar-bonyl)alanine in 4 1 dichloromethane/dimethylformamide treated with 1-hydroxy-benzotriazole and dicyclohexylcarbodiimide, stirred for 30 min, 25% aq. NH3 added, and stirred for 3-5 h until reaction complete (t.l.c.) - N-(4-methoxybenzyloxycar-bonyl)alanine amide. Y 83%. The method is high-yielding and racemization-free. F.e. inch Boc- and Cbz-aminoacid and dipeptide derivs. s. S.-T. Chen et al.. Synthesis 1989, 37-8 with 2-ethoxy-N-ethoxycarbonyl-l,2-dihydroquinoline and NH4HCO3 cf. S. Nozaki, I. Muramatsu, Bull. Chem. Soc. Japan 61, 2647-8 (1988). 

Sodium bis(trimethylsilyl)amide a-Aminocarboxylic acid esters from halides Synthesis with addition of 2 C-atoms... 

All proteins are copolymers of which the monomeric units can be any of the approximately 20 naturally occurring L-a-aminocarboxylic acids, NH2—CHR—COOH. Historically, the amide linkages in these macromolecules are called peptide linkages. Unipolymers are called poly(a-amino acids), copolymers with molecular weights of less than about 10,000 are called polypeptides, and copolymers with a molecular weight greater than about 10,000 are called proteins. In some important classes of proteins all the molecules of a specific protein are identical, i.e., they have the same arrangement and number of the various aminocarboxylic acids in the chain. 

Reactions with a,j(5-ethylenecarboxylic acid amides )3-Aminocarboxylic acid amides Michael addition... 

Potassium/tert-butanol a-Aminocarboxylic acids from carboxylic acid amides via N-chlorocarboxylic acid amides... 

Peptides (s. a. Carboxylic acid amides, subst., Peptoids) exchange of a-aminocarboxylic acids, terminal, in - 11, 569s32... 

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