A Convenient Preparation of ß-Amino Acids by Alkaline Hydrolysis of Dihydrouracils

Preparation of Achiral and of Enantiopure Geminally Disubstituted β-Amino Acids for β-Peptide Synthesis

“…[36] [37] (c) Threecomponent Mannich reaction of a ketone, NH 3 , and a malonic acid derivative. [38] [39] (d) Ritter transformation [40] of 3-hydroxycarboxylates with nitriles in the presence of conc.…”

The [2+2] Photocycloaddition of Uracil Derivatives with Ethylene as a General Route to cis-Cyclobutane β-Amino Acids

“…In an attempt to circumvent the recyclization problem, we attempted the transformation of 3d and 3l into b-amino acids 4d and 4l directly, through use of more strongly basic conditions (heating in 1 M aq NaOH), as suggested in the literature for other dihydrouracils. 24 Unfortunately, only degradation was observed. Practical difficulties (due to very poor solubility) during the isolation and purification of the phenyl derivative 4c reduced the final yield of this compound, while cyclobutane diamino acid derivative 4i was partially deprotected in the acidic reaction medium and was accompanied by the unprotected compound 4g.…”

An Efficient Two‐Step Preparation of α‐, β‐, γ‐ or δ‐Amino Acids from 2‐Pyrazinones, 2‐Hydroxypyrimidines or 2‐Pyridones Respectively

“…[17] Although under basic condition the reaction gave the desired product, the amino acids obtained were not pure. [17] All of these procedures are limited to multi-step synthesis, high reaction temperature, harsh conditions, the purity of the final product, the availability and the selection of appropriate catalyst for the preparation of starting intermediates. In general, these reactions are not amenable for scale-up and gave variable yields.…”

“…[11c] Another example containing 2‐piperidone skeleton and which serves as precursors to amino acids is dihydrouracil. Acid hydrolysis of 6‐substituted dihydrouracils at 160 °C led to cleavage of the ring and formation of β‐aminopropionic acid derivatives in low yield with unsaturated compounds as the main products . Although under basic condition the reaction gave the desired product, the amino acids obtained were not pure .…”

“…Acid hydrolysis of 6‐substituted dihydrouracils at 160 °C led to cleavage of the ring and formation of β‐aminopropionic acid derivatives in low yield with unsaturated compounds as the main products . Although under basic condition the reaction gave the desired product, the amino acids obtained were not pure . All of these procedures are limited to multi‐step synthesis, high reaction temperature, harsh conditions, the purity of the final product, the availability and the selection of appropriate catalyst for the preparation of starting intermediates.…”