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1.
Bioorg Med Chem ; 23(19): 6355-63, 2015 Oct 01.
Article in English | MEDLINE | ID: mdl-26344592

ABSTRACT

1-Aryl- and 2-aryl-1,2,3-triazoles were synthesized by N-arylation of the corresponding azoles using aryl iodides. The deprotometalations of 1-phenyl-1,2,3-triazole and -1,2,4-triazole were performed using a 2,2,6,6-tetramethylpiperidino-based mixed lithium-zinc combination and occurred at the most acidic site, affording by iodolysis the 5-substituted derivatives. Dideprotonation was noted from 1-(2-thienyl)-1,2,4-triazole by increasing the amount of base. From 2-phenyl-1,2,3-triazoles, and in particular from 2-(4-trifluoromethoxy)phenyl-1,2,3-triazole, reactions at the 4 position of the triazolyl, but also ortho to the triazolyl on the phenyl group, were observed. The results were analyzed with the help of the CH acidities of the substrates, determined in THF solution using the DFT B3LYP method. 4-Iodo-2-phenyl-1,2,3-triazole and 4-iodo-2-(2-iodophenyl)-1,2,3-triazole were next involved in Suzuki coupling reactions to furnish the corresponding 4-arylated and 4,2'-diarylated derivatives. When evaluated for biological activities, the latter (which are resveratrol analogues) showed moderate antibacterial activity and promising antiproliferative effect against MDA-MB-231 cell line.


Subject(s)
Antineoplastic Agents/chemistry , Stilbenes/chemistry , Triazoles/chemistry , Anti-Bacterial Agents/chemical synthesis , Anti-Bacterial Agents/chemistry , Anti-Bacterial Agents/pharmacology , Antineoplastic Agents/chemical synthesis , Antineoplastic Agents/pharmacology , Cell Line, Tumor , Cell Proliferation/drug effects , Crystallography, X-Ray , Gram-Negative Bacteria/drug effects , Gram-Positive Bacteria/drug effects , Humans , Microbial Sensitivity Tests , Molecular Conformation , Resveratrol , Stilbenes/chemical synthesis , Stilbenes/pharmacology
2.
Org Biomol Chem ; 12(9): 1475-87, 2014 Mar 07.
Article in English | MEDLINE | ID: mdl-24445663

ABSTRACT

1-Aryl-1H-benzotriazoles and -1H-indazoles were synthesized, and their deproto-metallation using the base prepared by mixing LiTMP with ZnCl2·TMEDA (1/3 equiv.) was studied. In the indazole series, reactions occurring at the 3 position were followed by ring opening, and functionalization of the substrate was only found possible (on the sulfur ring) using 2-thienyl as aryl group. In the benzotriazole series, either mono- or bis-deprotonation (depending on the amount of base employed) was achieved with phenyl, 4-methoxyphenyl and 2-thienyl as aryl group, and bis-deprotonation in the case of 4-chlorophenyl and 4-trifluoromethylphenyl. The experimental results were analyzed with the help of the CH acidities of the substrates, determined in THF solution using the DFT B3LYP method.


Subject(s)
Indazoles/chemical synthesis , Lithium/chemistry , Organometallic Compounds/chemistry , Triazoles/chemical synthesis , Zinc/chemistry , Indazoles/chemistry , Models, Molecular , Organometallic Compounds/chemical synthesis , Quantum Theory , Triazoles/chemistry
3.
Chemistry ; 19(24): 7944-60, 2013 Jun 10.
Article in English | MEDLINE | ID: mdl-23584978

ABSTRACT

With the aim of synthesizing biaryl compounds, several aromatic iodides were prepared by the deprotonative metalation of methoxybenzenes, 3-substituted naphthalenes, isoquinoline, and methoxypyridines by using a mixed lithium/zinc-TMP (TMP=2,2,6,6-tetramethylpiperidino) base and subsequent iodolysis. The halides thus obtained, as well as commercial compounds, were cross-coupled under palladium catalysis (e.g., Suzuki coupling with 2,4-dimethoxy-5-pyrimidylboronic acid) to afford various representative biaryl compounds. Deprotometalation of the latter compounds was performed by using the lithium/zinc-TMP base and evaluated by subsequent iodolysis. The outcome of these reactions has been discussed in light of the CH acidities of these substrates, as determined in THF solution by using the DFT B3LYP method. Except for in the presence of decidedly lower pKa values, the regioselectivities of the deprotometalation reactions tend to be governed by nearby coordinating atoms rather than by site acidities. In particular, azine and diazine nitrogen atoms have been shown to be efficient in inducing the reactions with the lithium/zinc-TMP base at adjacent sites (e.g., by using 1-(2-methoxyphenyl)isoquinoline, 4-(2,5-dimethoxyphenyl)-3-methoxypyridine, or 5-(2,5-dimethoxyphenyl)-2,4-dimethoxypyrimidine as the substrate), a behavior that has already been observed upon treatment with lithium amides under kinetic conditions. Finally, the iodinated biaryl derivatives were involved in palladium-catalyzed reactions.


Subject(s)
Heterocyclic Compounds/chemical synthesis , Hydrocarbons, Iodinated/chemistry , Lithium/chemistry , Palladium/chemistry , Piperidines/chemical synthesis , Zinc/chemistry , Amides/chemistry , Catalysis , Combinatorial Chemistry Techniques , Heterocyclic Compounds/chemistry , Kinetics , Models, Chemical , Molecular Structure , Piperidines/chemistry
4.
Org Biomol Chem ; 10(25): 4878-85, 2012 Jul 07.
Article in English | MEDLINE | ID: mdl-22610262

ABSTRACT

2-Aryl-1,2,3-triazoles were synthesized by cyclization of the corresponding glyoxal arylosazones, generated from commercial arylhydrazines. The deproto-metallation of 2-phenyl-1,2,3-triazole was attempted using different 2,2,6,6-tetramethylpiperidino-based mixed lithium-metal (Zn, Cd, Cu, Co, Fe) combinations, giving results in the case of Zn, Cd, and Cu. The lithium-zinc combination was next selected to apply the deprotonation-iodination sequence to all the 2-aryl-1,2,3-triazoles synthesized. The results were analyzed with the help of the CH acidities of the substrates, determined in THF solution using the DFT B3LYP method.


Subject(s)
Metals/chemistry , Triazoles/chemical synthesis , Acids/chemistry , Models, Molecular , Molecular Structure
5.
Org Lett ; 14(3): 894-7, 2012 Feb 03.
Article in English | MEDLINE | ID: mdl-22272556

ABSTRACT

The Friedel-Crafts reaction of (η(4)-tetraphenylcyclobutadiene)(η(5)-carbomethoxycyclopentadienyl)cobalt with acid chlorides/aluminum chloride resulted exclusively in para-phenyl acylation. Both monoacylated (1.1 equiv of RCOCl/AlCl(3)) and tetraacylated products (>4 equiv of RCOCl/AlCl(3)) were synthesized. Reaction of PhCC(o-RC(6)H(4)) (R = Me, i-Pr) with Na(C(5)H(4)CO(2)Me) and CoCl(PPh(3))(3) gave predominantly (η(4)-1,3-diaryl-2,4-diphenylcyclobutadiene)(η(5)-carbomethoxycyclopentadienyl)cobalt metallocenes (1,3-[trans] vs 1,2-[cis] selectivity up to 6:1). Conformational control of Friedel-Crafts reactions on the major isomers gave exclusively para-acylation of the unsubstituted phenyl groups.

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