43131-46-0Relevant academic research and scientific papers
Practical synthesis of tetrazoles from amides and phosphorazidates in the presence of aromatic bases
Ishihara, Kotaro,Ishihara, Kazuki,Tanaka, Yota,Shioiri, Takayuki,Matsugi, Masato
supporting information, (2022/02/02)
Tetrazoles were effectively synthesized from amides using diphenyl phosphorazidate or bis(p-nitrophenyl) phosphorazidate in the presence of aromatic bases. Various amides underwent the proposed cycloaddition reaction to provide the corresponding tetrazoles. Studies on the racemization of chiral substrates were also performed. Overall, the proposed synthesis method enables the preparation of 1,5-disubstituted and 1-substituted tetrazoles, and 5-substituted 1H-tetrazoles without using toxic or explosive reagents.
An Expeditious Approach to Tetrazoles from Amides Utilizing Phosphorazidates
Ishihara, Kotaro,Shioiri, Takayuki,Matsugi, Masato
supporting information, p. 6244 - 6247 (2020/07/24)
A novel method was developed for the synthesis of tetrazoles from amides utilizing diphenyl phosphorazidate or bis(p-nitrophenyl) phosphorazidate as both the activator of amide-oxygen for elimination and azide source. Various amides were converted into th
An Environmentally Friendly Method for N-Methylation of 5-Substituted 1H-Tetrazoles with a Green Methylating Reagent: Dimethyl Carbonate
Xie, Aming,Zhang, Qiang,Liu, Yangyang,Feng, Liandong,Hu, Xinyu,Dong, Wei
, p. 1483 - 1487 (2015/10/06)
An environmentally friendly method was established for the N-methylation of the 5-substituted 1H-tetrazoles with a green reagent: DMC. DABCO was the optimal catalyst, and hazardous chemicals were avoided in this protocol. A plausible catalytic mechanism is proposed, which consists of a DABCO-activated process and a thermally induced rearrangement of tetrazole carbamates.
Tetrazoles: LIV. Alkylation of 5-aryltetrazoles under microwave activation
Efimova,Artamonova,Koldobskii
experimental part, p. 725 - 727 (2009/10/11)
The application of microwave activation (MWA) to alkylation of 5-aryltetrazoles with dimethyl sulfate in organic solvents did not considerably affect the selectivity of the process compared to nonactivated procedure. A significant enhancement of the selec
Progress in the proxifan class: heterocyclic congeners as novel potent and selective histamine H3-receptor antagonists
Grassmann, Sven,Sadek, Bassem,Ligneau, Xavier,Elz, Sigurd,Ganellin, C. Robin,Arrang, Jean-Michel,Schwartz, Jean-Charles,Stark, Holger,Schunack, Walter
, p. 367 - 378 (2007/10/03)
Histamine H3 receptors are critically involved in the pathophysiology of several disorders of the central nervous system (CNS). Among other families of H3-receptor ligands, the proxifan class has recently been described to contain numerous potent histamine H3-receptor antagonists, e.g. ciproxifan or imoproxifan. In the present study, we report on the design of novel heterocyclic proxifan analogues and their antagonist potencies at histamine H3 receptors. The new compounds were tested for in vitro and in vivo H3-receptor antagonist potencies in different species as well as for H3-receptor selectivity vs. H1 and H2 receptors. In vitro, all compounds investigated proved to be potent H3-receptor antagonists in the rat as well as in the guinea-pig. In addition, they showed good to high oral CNS potency in vivo in mice. Especially, oxadiazole derivatives 24-26 displayed nanomolar antagonist activity in vitro and high potency in vivo (ED50=0.47-0.57 mg/kg). The results show that the additional heteroaromatic moieties might act as bioisosteres of the ketone or oxime moieties of ciproxifan or imoproxifan, respectively, and might cause divergent pharmacokinetic properties. Thus, these novel H3-receptor antagonists are interesting leads for further development. Copyright
TETRAZOLES. XVI. ALKYLATION OF TETRAZOLES UNDER THE CONDITIONS OF PHASE-TRANSFER CATALYSIS
Osipova, T. F.,Ostrovskii, V. A.,Koldobskii, G. I.,Erusalimskii, G. B.
, p. 357 - 362 (2007/10/02)
The alkylation of tetrazole and 5-substituted tetrazoles with dimethyl sulfate and methyl iodide in the two-phase methylene chloride-water system in the presence of tetrabutylammonium bromide was investigated.The alkylation of tetrazoles with methyl iodide takes place in the organic phase, while that with dimethyl sulfate takes place both in the organic and in the aqueous phases.The ratio of the isomeric tetrazoles formed during the alkylation of 5-aryltetrazoles by methyl iodide correlate with the substituent constants ?.The use of phase-transfer catalysis during the alkylation of tetrazoles does not lead to a change in the selectivity of the reaction.
Positional Selectivity of the Methylation of 5-Substituted Tetrazolate Anions
Spear, Robert J.
, p. 2453 - 2468 (2007/10/02)
The methylation of a series of 15 sodium 5-substituted tetrazolates using iodomethane in acetone/water (4:1) has been studied.The reaction yields both 1- and 2-methyl products, and the ratio of these products is discussed in terms of the nature of the 5-substituent.Electronic and steric effects dominate the reaction pathway; both increased substituent electronegativity and steric bulk lead to predominant methylation at N 2.Sodium 5-ethoxycarbonyltetrazolate (3n) goes against this trend and an intermediate is proposed where the incoming electrophile is associated with the ester carbonyl group.
