Pyrazoles have been focus of a large number of investigations in the design and
synthesis of novel biologically active agents that show remarkable medicinal
activities. Although pyrazoles have been studied for over a century as an important
class of heterocyclic compounds, they still continue to attract considerable attention
due to the wide range of medicinal activities they possess. Recent studies have
shown that combination of a ferrocenyl unit with structural features of pyrazoles can
lead to products with enhanced or/and unexpected biological activity since several
ferrocene derivatives have already been shown to be active against a number of
tumors. As a result, we have investigated the reaction of 3-ferrocenylpropynal with
hydrazinium salts. As anticipated, these reactions afforded two kinds of pyrazoles,
namely 1-alkyl/aryl-5-ferrocenylpyrazoles (1,5-isomer) and 1-alkyl/aryl-3-
ferrocenylpyrazoles (1,3-isomer). In most cases, 1,5-pyrazole isomers have resulted
from these reactions as the single or the major product of the reactions. The
structures of 1-benzyl-5-ferrocenylpyrazole, 1-phenyl-5-ferrocenyl-pyrazole and 1-
(2-hydroxy-ethyl)-3-ferrocenylpyrazole were identified by X-ray single crystal
analysis. The analogous reactions between 3-phenylpropynal and hydrazinium salts
were also studied, which afforded 1-alkyl/aryl-5-phenylpyrazoles (1,5-isomer) and/or
v
1-alkyl/aryl-3-phenylpyrazoles (1,3-isomer). The regioselectivity of the reactions is
mainly governed by the nature of the substituents in hydrazine derivative.
| Identifer | oai:union.ndltd.org:METU/oai:etd.lib.metu.edu.tr:http://etd.lib.metu.edu.tr/upload/3/12609769/index.pdf |
| Date | 01 August 2008 |
| Creators | Pinar, Ayse Nur |
| Contributors | Zora, Metin |
| Publisher | METU |
| Source Sets | Middle East Technical Univ. |
| Language | English |
| Detected Language | English |
| Type | M.S. Thesis |
| Format | text/pdf |
| Rights | To liberate the content for public access |
Page generated in 0.0018 seconds