On the synthesis of heterocyclic dendrons

Abstract

Dedicated to Professor Marcial Moreno-Mañas on the occasion of his 60th birthday (received 20 Dec 01; accepted 28 Jan 02; published on the web 05 Feb 02) AbstractThe synthesis of dendrons 1 -7 bearing azole (pyrazole, imidazole and 1,2,4-triazole) moieties is described. The synthesis of these compounds was carried out using different approaches: functionalisation of the methylene bridge of bispirazol-1-ylmethane derivates; double Michael addition of 1,2,4-triazole to methyl propiolate, nucleophilic substitution of halide from the corresponding 2,6-dichloro-4-methylpyridine or 1,3-bis(bromomethyl)benzene derivatives, and nucleophilic substitution on p-hydroxybenzaldehyde dimethylacetal. Schotten-Baumann reaction with 1,3,5-trischlorocarbonylbenzene and Sonogashira coupling with 1,3,5-triethynylbenzene were used for the synthesis of G0-dendrimers.

Synthesis and characterization of metallodendritic palladium-biscarbene complexes derived from 1,1′-methylenebis(1,2,4-triazole)

“…The syntheses of products 2-9 have been described previously. 16,36 Anhydrous dimethylformamide was obtained from Fisher (Fair Lawn, NJ) and transferred into a helium atmosphere drybox (Vacuum Atmospheres Corp., Hawthorne, CA). Electrochemical grade tetra-n-butylammonium phosphate was obtained from Fluka and transferred into the drybox.…”

Supramolecular Assemblies between a New Series of Gemini-Type Amphiphiles and TPPS at the Air/Water Interface: Aggregation, Chirality, and Spacer Effect

“…Anionic porphyrin, tetrakis(4-sulfonatonphenyl)porphine (TPPS), was purchased from Tokyo Kasei and used without further purification. Synthesis of the gemini amphiphiles was carried out from the starting material of 2-heptadecyl-1 H -imidazole (Tokyo Kasei) in two steps. , The intermediate 1-ethyl-2-heptadecyl-1 H -imidazole was synthesized by nucleophilic reaction of 2-heptadecyl-1 H -imidazole with bromoethane. Then the compound was reacted with dibromoalkane with different alkane lengths.…”

Dendrimers Designed for Functions: From Physical, Photophysical, and Supramolecular Properties to Applications in Sensing, Catalysis, Molecular Electronics, Photonics, and Nanomedicine

“…With iminophosphorane G 4 dendrimers, Pd black formed extensively, 888 but with pyridylimine ligands, higher rates, conversions, and stability were found. 889 Tris-and hexanuclear (star-shaped) N-heterocyclic carbene complexes 886 have been shown to catalyze Heck coupling between iodobenzene or activated bromobenzes with acrylates, although truly dendritic complexes are not known 890,891 Heck reactions between iodobenzene and methyl acrylates, which were not productive with [PdCl 2 (PPh 3 ) 2 ] as the catalyst in scCO 2 , became possible with 40% conversion when (CH 2 ) 3 SiMe 2 Et tails were introduced in the para position of the phenyl rings of the ligands (Figure 46). 892 Negative dendritic effects upon increasing dendron generation in catalysis of bidentate phosphine-Pd-dendronized support for the Heck reaction have been reported.…”