Molecules 2007, 12(1), 60-73; doi:10.3390/12010060
Article

A Convenient Approach to Heterocyclic Building Blocks: Synthesis of Novel Ring Systems Containing a [5,6]Pyrano[2,3-c]pyrazol-4(1H)-one Moiety

* email and email
Received: 15 January 2007; in revised form: 24 January 2007 / Accepted: 24 January 2007 / Published: 26 January 2007
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Abstract: Starting from commercially available educts, a straightforward synthetic route to new heterocyclic building blocks is exemplified with the one- or two-step synthesis of tri-, tetra-, or pentacyclic ring systems. Representatives of the following novel ring systems are prepared from 3-methyl-1-phenyl-2-pyrazolin-5-one and the corresponding o-halo-arenecarbonyl chloride using calcium hydroxide in refluxing 1,4-dioxane: pyrimidino[4',5':5,6]pyrano[2,3-c]pyrazol-4(1H)-one, thieno[3',2':5,6]pyrano[2,3c]pyrazol- 4-(1H)-one, thieno[3',4':5,6]pyrano[2,3-c]pyrazol-4(1H)-one, thieno[3'',2'':4',5']thieno[2',3':5,6]-pyrano[2,3-c]pyrazol-4(1H)-one, [1,3]dioxolo[5',6'][1]benzothieno[2',3':5,6]pyrano-[2,3-c]- pyrazol-4(1H)-one, pyridazino[4',3':5,6]pyrano[2,3-c]pyrazol-4(1H)-one and pyrazolo-[4'',3'':5',6']pyrido[3',4':5,6]pyrano[2,3-c]pyrazol-4(1H)-one. While the latter two ring systems are directly obtained due to a spontaneous intramolecular substitution reaction, in the other reactions uncyclised 4-aroylpyrazol-5-ols are produced, which are cyclised into the target heterocycles in a subsequent synthetic step (i.e. treatment with NaH in DMF). Detailed NMR spectroscopic investigations (1H-, 13C-, 15N-) with the obtained compounds were undertaken to unambiguously prove the new structures.
Keywords: Fused-ring systems;NMR spectroscopy;heterocyclic building blocks;acylations;pyrazolones.
PDF Full-text Download PDF Full-Text [146 KB, uploaded 18 June 2014 19:27 CEST]

Export to BibTeX |
EndNote


MDPI and ACS Style

Eller, G.; Holzer, W. A Convenient Approach to Heterocyclic Building Blocks: Synthesis of Novel Ring Systems Containing a [5,6]Pyrano[2,3-c]pyrazol-4(1H)-one Moiety. Molecules 2007, 12, 60-73.

AMA Style

Eller G, Holzer W. A Convenient Approach to Heterocyclic Building Blocks: Synthesis of Novel Ring Systems Containing a [5,6]Pyrano[2,3-c]pyrazol-4(1H)-one Moiety. Molecules. 2007; 12(1):60-73.

Chicago/Turabian Style

Eller, Gernot; Holzer, Wolfgang. 2007. "A Convenient Approach to Heterocyclic Building Blocks: Synthesis of Novel Ring Systems Containing a [5,6]Pyrano[2,3-c]pyrazol-4(1H)-one Moiety." Molecules 12, no. 1: 60-73.

Molecules EISSN 1420-3049 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert