A New Synthesis of 4,5,6,7-Tetrahydropyrazolo[1,5-c]pyrimidines by a Retro-Mannich Cascade Rearrangement

2014 ◽  
Vol 67 (3) ◽  
pp. 420 ◽  
Author(s):  
Raffaele Colombo ◽  
Kyu Ok Jeon ◽  
Donna M. Huryn ◽  
Matthew G. LaPorte ◽  
Peter Wipf
Keyword(s):  
Mannich Reaction ◽  
Medicinal Chemistry ◽  
Hydrolysis Product ◽  
Building Blocks ◽  
Biological Applications ◽  
Heterocyclic Chemistry ◽  
New Synthesis ◽  
Rearrangement Process

We discovered a new retro-Mannich reaction of in situ prepared pyrazolopyridines to give pyrazolopyrimidines that have hitherto been underrepresented in the heterocyclic chemistry literature. The isolation of a linear hydrolysis product supports a mechanistic hypothesis for this rearrangement process. In order to establish a broader access and explore potential biological applications for these medicinal chemistry building blocks, we investigated the scope of the reaction and generated small amine- as well as amide-based libraries through reductive aminations and amide couplings, respectively.

Pyrazole Carboxylic Acid and Derivatives: Synthesis and Biological Applications

2020 ◽  
Vol 17 ◽  
Author(s):  
Adnan Cetin
Keyword(s):  
Organic Chemistry ◽  
Biological Activity ◽  
Carboxylic Acid ◽  
Heterocyclic Compounds ◽  
Medicinal Chemistry ◽  
Biological Activities ◽  
Building Blocks ◽  
Literature Survey ◽  
Synthetic Methods ◽  
Biological Applications

: The heterocyclic compounds are the building blocks for synthesis of the different biological active compounds in the organic chemistry. Heterocyclic compounds have versatile synthetic applicability and biological activity. Pyrazole carboxylic acid derivatives are significant scaffold structures in heterocyclic compounds due to biologic activities such as antimicrobial, anticancer, inflammatory, antidepressant, antifungal anti-tubercular and antiviral etc. The aim of this mini-review is an overview synthesis of pyrazole carboxylic acid derivatives and their biologic applications. The summarized literature survey presents in detail biological activities of pyrazole carboxylic acid derivatives and their various synthetic methods. This mini-review can be guide to many scientists in medicinal chemistry.

Laboratory and in-situ analysis of comet dust

1988 ◽  
Vol 46 ◽  
pp. 8-9
Author(s):  
D.E. Brownlee ◽  
A.L. Albee
Keyword(s):  
Electron Microscopy ◽  
Solar System ◽  
Laboratory Study ◽  
Isotopic Analysis ◽  
Building Blocks ◽  
Sem Analysis ◽  
Early Solar System ◽  
Cometary Material ◽  
Comet Dust

Comets are primitive, kilometer-sized bodies that formed in the outer regions of the solar system. Composed of ice and dust, comets are generally believed to be relic building blocks of the outer solar system that have been preserved at cryogenic temperatures since the formation of the Sun and planets. The analysis of cometary material is particularly important because the properties of cometary material provide direct information on the processes and environments that formed and influenced solid matter both in the early solar system and in the interstellar environments that preceded it.The first direct analyses of proven comet dust were made during the Soviet and European spacecraft encounters with Comet Halley in 1986. These missions carried time-of-flight mass spectrometers that measured mass spectra of individual micron and smaller particles. The Halley measurements were semi-quantitative but they showed that comet dust is a complex fine-grained mixture of silicates and organic material. A full understanding of comet dust will require detailed morphological, mineralogical, elemental and isotopic analysis at the finest possible scale. Electron microscopy and related microbeam techniques will play key roles in the analysis. The present and future of electron microscopy of comet samples involves laboratory study of micrometeorites collected in the stratosphere, in-situ SEM analysis of particles collected at a comet and laboratory study of samples collected from a comet and returned to the Earth for detailed study.

Cascade CuH-Catalyzed Conversion of Alkynes to Enantioenriched 1,1-Disubstituted Products

2019 ◽  
Author(s):  
De-Wei Gao ◽  
Yang Gao ◽  
Huiling Shao ◽  
Tian-Zhang Qiao ◽  
Xin Wang ◽  
...  
Keyword(s):  
Organic Synthesis ◽  
Medicinal Chemistry ◽  
Proteasome Inhibitors ◽  
Building Blocks ◽  
Unique Role ◽  
Efficient Strategy ◽  
Carbon Centers ◽  
Rapid Access ◽  
Cascade Catalysis ◽  
Privileged Scaffolds

Enantioenriched <i>α</i>-aminoboronic acids play a unique role in medicinal chemistry and have emerged as privileged pharmacophores in proteasome inhibitors. Additionally, they represent synthetically useful chiral building blocks in organic synthesis. Recently, CuH-catalyzed asymmetric alkene hydrofunctionalization has become a powerful tool to construct stereogenic carbon centers. In contrast, applying CuH cascade catalysis to achieve reductive 1,1-difunctionalization of alkynes remains an important, but largely unaddressed, synthetic challenge. Herein, we report an efficient strategy to synthesize <i>α</i>-aminoboronates <i>via </i>CuH-catalyzed hydroboration/hydroamination cascade of readily available alkynes. Notably, this transformation selectively delivers the desired 1,1-heterodifunctionalized product in favor of alternative homodifunctionalized, 1,2-heterodifunctionalized, or reductively monofunctionalized byproducts, thereby offering rapid access to these privileged scaffolds with high chemo-, regio- and enantioselectivity.<br>

scholarly journals Exploring Cu/Al cluster growth and reactivity: from embryonic building blocks to intermetalloid, open-shell superatoms

2021 ◽  
Author(s):  
Max Schütz ◽  
Christian Gemel ◽  
Maximilian Muhr ◽  
Christian Jandl ◽  
Samia Kahlal ◽  
...  
Keyword(s):  
Closed Shell ◽  
Building Blocks ◽  
Open Shell ◽  
Cluster Growth ◽  
Powerful Technique

Cu/Al cluster growth reactions leading to open- and closed-shell superatoms are investigated. Therein, LIFDI-MS is presented as a powerful technique for the in situ detection of cluster identities and reactivity patterns.

scholarly journals Janus All‐Cis 2,3,4,5,6‐Pentafluorocyclohexyl Building Blocks Applied to Medicinal Chemistry and Bioactives Discovery Chemistry

2021 ◽  
Author(s):  
Joshua L. Clark ◽  
Rifahath M. Neyyappadath ◽  
Cihang Yu ◽  
Alexandra M. Z. Slawin ◽  
David B. Cordes ◽  
...  
Keyword(s):  
Medicinal Chemistry ◽  
Building Blocks

Cyclopropyl Building Blocks for Organic Synthesis. Part 102. A Convenient New Synthesis of 3-Substituted ?-Lactams Formally Derived from 1-(Aminomethyl)cyclopropanecarboxylic Acids.

ChemInform ◽  
2005 ◽  
Vol 36 (5) ◽  
Author(s):  
Alessandra Zanobini ◽  
Martina Gensini ◽  
Joerg Magull ◽  
Denis Vidovic ◽  
Sergei I. Kozhushkov ◽  
...  
Keyword(s):  
Organic Synthesis ◽  
Building Blocks ◽  
New Synthesis
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