Synthesis and Characterization of Novel Methyl (3)5-(N-Boc-piperidinyl)-1H-pyrazole-4-carboxylates

Molecules

Eglė Arbačiauskienė¹  Vilija Kederienė¹  Aurimas Bieliauskas²  Vaida Milišiūnaitė²  Algirdas Šačkus²  Gita Matulevičiūtė²  Miglė Dagilienė²  Neringa Kleizienė²  Greta Ragaitė²  Frank A. Sløk³ 

[1] Department of Organic Chemistry, Kaunas University of Technology, Radvilėnų pl. 19, LT-50254 Kaunas, Lithuania;Institute of Synthetic Chemistry, Kaunas University of Technology, K. Baršausko g. 59, LT-51423 Kaunas, Lithuania;Vipergen ApS, Gammel Kongevej 23A, V DK-1610 Copenhagen, Denmark;

关键词: heterocyclic amino acids;    pyrazoles;    piperidines;    β-keto esters;    enamines;    hydrazines;   

DOI  :  10.3390/molecules26133808

来源: DOAJ

【 摘 要 】

Series of methyl 3- and 5-(N-Boc-piperidinyl)-1H-pyrazole-4-carboxylates were developed and regioselectively synthesized as novel heterocyclic amino acids in their N-Boc protected ester form for achiral and chiral building blocks. In the first stage of the synthesis, piperidine-4-carboxylic and (R)- and (S)-piperidine-3-carboxylic acids were converted to the corresponding β-keto esters, which were then treated with N,N-dimethylformamide dimethyl acetal. The subsequent reaction of β-enamine diketones with various N-mono-substituted hydrazines afforded the target 5-(N-Boc-piperidinyl)-1H-pyrazole-4-carboxylates as major products, and tautomeric NH-pyrazoles prepared from hydrazine hydrate were further N-alkylated with alkyl halides to give 3-(N-Boc-piperidinyl)-1H-pyrazole-4-carboxylates. The structures of the novel heterocyclic compounds were confirmed by ¹H-, ¹³C-, and ¹⁵N-NMR spectroscopy and HRMS investigation.

【 授权许可】

Unknown