Synthesis and Ring Opening of Methyl 2-Alkyl-3-(alkyl/aryl)-1-benzoylaziridine-2-carboxylates: Synthesis of Polysubstituted Amino Acids

Optically active α-hydroxy acids derived from amino acids have been synthesized and polymerized into new biodegradable polyesters. The variety of functional side chains enables the design of positively charged, negatively charged, hydrophobic and hydrophilic chiral building blocks or any combination of these constituents. Hydroxy acids of 15 natural amino acids were prepared with retention of configuration using a straightforward and reliable method of diazotization of α-amino acids. Polyesters were synthesized from these hydroxy acids by a number of methods: direct condensation in bulk, microwave assisted synthesis and ring opening polymerization. The molecular weight of the prepared polymers ranges between 2000 to 5000Da for the direct condensation and the microwave methods, whereas the ring opening polymerization results in high molecular weight polymers (20000 to 30000Da). The polymers were analyzed for their optical activity (Circular Dichroism Spectroscopy), thermal properties (DSC), solubility, molecular weight and polydispersity (GPC), and aqueous degradation. These polymers were tested for their compatibility to neuronal cells growth and differentiation.

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Synthesis of poly(2-ethyl-2-oxazoline)-block-polypeptide copolymers by combination of ring-opening polymerization of oxazoline and polycondensation of activated urethane derivatives of α-amino acids

Polymer Bulletin ◽

10.1007/s00289-018-2313-2 ◽

2018 ◽

Vol 75 (11) ◽

pp. 5075-5088 ◽

Cited By ~ 5

Author(s):

Koksal Karadag ◽

Shuhei Yamada ◽

Takeshi Endo

Keyword(s):

Amino Acids ◽

Ring Opening ◽

Ring Opening Polymerization ◽

Derivatives Of

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An Efficient Synthesis of Functionalized 2H-1,3,5-Oxadiazines via Metal-Carbenoid-Induced 1,2,4-Oxadiazole Ring Cleavage

Synthesis ◽

10.1055/s-0040-1707278 ◽

2020 ◽

Vol 53 (02) ◽

pp. 348-358

Author(s):

Mikhail S. Novikov ◽

Julia O. Strelnikova ◽

Nikolai V. Rostovskii ◽

Olesya V. Khoroshilova ◽

Alexander F. Khlebnikov

Keyword(s):

Ring Opening ◽

Ring Cleavage ◽

Efficient Synthesis ◽

Alkyl Aryl ◽

Diazo Esters ◽

Reaction Proceeds

AbstractA high-yielding method for the synthesis of 2H-1,3,5-oxadiazines by rhodium(II)- or copper(II)-catalyzed reaction of 1,2,4-oxadiazoles with α-diazo esters has been developed. The reaction proceeds via attack of the metallocarbenoid on the oxadiazole N2 atom followed by ring opening/1,6-electrocyclization and enables the introduction of alkyl, aryl, oxy, and amino substituents into the 6-position and electron-withdrawing groups into the 2-position of 1,3,5-oxadiazine. The N2-attack and the N4-attack of the carbenoid cause different oxadiazole ring openings, which are controlled by the substitution at C5. The presence of a substituent at this position is a prerequisite for the N2-attack to occur, leading to the formation of 1,3,5-oxadiazines.

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