1826-12-6Relevant academic research and scientific papers
Synthesis of 1-Pyrroline by Denitrogenative Ring Expansion of Cyclobutyl Azides under Thermal Conditions
Ban, Kazuho,Miki, Yuya,Sajiki, Hironao,Sawama, Yoshinari,Tomita, Naohito
, p. 3481 - 3484 (2021/06/17)
We herein report an efficient and systematic synthesis of 1-pyrrolines from cyclobutyl azides under thermal and neutral conditions. The reaction proceeded without any additional reagents, and nitrogen was generated as the sole by-product. Furthermore, the generated 1-pyrrolines could be continuously transformed into pyrroles, N-Boc-amines, and oxaziridines in an one-pot manner. (Figure presented.).
Regio- And Stereoselective Synthesis of Thiazole-Containing Triarylethylenes by Hydroarylation of Alkynes
Lee, Woohyeong,Shin, Changhoon,Park, Soo Eun,Joo, Jung Min
, p. 12913 - 12924 (2019/09/12)
Thiazole-containing π-conjugated moieties are important structural units in the development of new electronic and photochromic materials. We have developed a Pd-catalyzed syn-hydroarylation reaction of diaryl alkynes with thiazoles that provides access to thiazole-containing triarylethylenes. Pd(II) complexes derived from Pd(0) species and carboxylic acids facilitated C-H functionalization of the unsubstituted thiazole with high C5 selectivity. The catalytic system was also compatible with other azoles, such as oxazoles and a pyrazole, allowing the stereoselective syntheses of various trisubstituted olefins.
Rhodium-catalyzed 2-methylthiolation reaction of thiazoles/oxazoles using 2-(methylthio)thiazole
Arisawa, Mieko,Nihei, Yuri,Yamaguchi, Masahiko
, p. 939 - 949 (2015/03/04)
RhH(PPh3)4 and 1,3-bis(dicyclohexyl)phosphinopropane (dcypp) catalyze the 2-methylthiolation of oxazoles and thiazoles using 2-(methylthio)thiazole as a thiolating reagent. The methylthio transfer reaction is under equilibrium, and various 2-methylthiolated thiazoles and oxazoles were obtained in moderate to good yields by removing thiazole under refluxing o-dichlorobenzene.
NaBH4-TMEDA and a palladium catalyst as efficient regio- and chemoselective system for the hydrodehalogenation of halogenated heterocycles
Chelucci, Giorgio,Figus, Susanna
, p. 191 - 209 (2014/07/21)
The pair NaBH4-TMEDA as hydride source and a palladium catalyst in THF prove to be an efficient system for the hydrodehalogenation of halogenated heterocycles with one or more heteroatoms. In general, Pd(OAc) 2-PPh3 rapidly hydrodehalogenates reactive halo-heterocycles such as bromo-pyridines, -quinolines, -thiophenes, -indoles, -imidazoles, etc., at room temperature in very good yields, whereas in most cases PdCl2(dppf) reduces less reactive halides such as chloro-pyridines, -quinolines, -pyrimidines and bromo-indoles, -benzofurans, etc. Moreover, PdCl2(tbpf) shows to be even more active removing the 2- and 5-chlorine from both thiophene and thiazole rings. The reaction conditions tolerate various functional groups, allowing highly chemoselective reactions in the presence of halide, ester, alkyne, alkene and nitrile substituents. Moreover, with a proper selection of the catalyst it is also possible to obtain a good control in the regioselective hydrodehalogenation of a variety of polyhalogenated substrates.
Programmed synthesis of arylthiazoles through sequential C-H couplings
Tani, Satoshi,Uehara, Takahiro N.,Yamaguchi, Junichiro,Itami, Kenichiro
, p. 123 - 135 (2014/01/06)
A programmed synthesis of privileged arylthiazoles via sequential C-H couplings catalyzed by palladium or nickel catalysts has been accomplished. This versatile protocol can supply all possible arylthiazole substitution patterns (2-aryl, 4-aryl, 5-aryl, 2
Novel series of 3-amino-N-(4-aryl-1,1-dioxothian-4-yl)butanamides as potent and selective dipeptidyl peptidase IV inhibitors
Nitta, Aiko,Fujii, Hideaki,Sakami, Satoshi,Satoh, Mikiya,Nakaki, Junko,Satoh, Shiho,Kumagai, Hiroki,Kawai, Hideki
, p. 7036 - 7040 (2013/01/15)
A series of novel 3-amino-N-(4-aryl-1,1-dioxothian-4-yl)butanamides were investigated as dipeptidyl peptidase IV (DPP-4) inhibitors. Introduction of a 4-phenylthiazol-2-yl group showed highly potent DPP-4 inhibitory activity. Among various derivatives, (3R)-3-amino-N-(4-(4-phenylthiazol-2-yl)-tetrahydro-2H- thiopyran-4-yl)-4-(2,4,5-trifluorophenyl)butanamide 1,1-dioxide (30) reduced blood glucose excursion in an oral glucose tolerance test by oral administration.
Room-temperature hydrodehalogenation of halogenated heteropentalenes with one or two heteroatoms
Chelucci, Giorgio,Baldino, Salvatore,Ruiu, Andrea
, p. 9921 - 9925,5 (2012/12/12)
The pair NaBH4-TMEDA as a hydride source and catalytic PdCl 2(dppf) in THF prove to be an efficient system for the hydrodehalogenation of bromo(chloro)-heteropentalenes with one or two heteroatoms, while Pd(OAc)2/PPh3 is able to reduce reactive haloheteropentalenes, and PdCl2(tbpf) allows the removal of the 2-chlorine from a thiophene ring. The reaction conditions tolerate various functional groups, allowing highly chemoselective reactions in the presence of halide, ester, alkyne, alkene, and nitrile substituents and also showing good efficiency in the regioselective hydrodehalogenation of a variety of polyhalogenated substrates.
Photochemistry of 3- and 5-phenylisothiazoles. Competing phototransposition pathways
Pavlik, James W.,Tongcharoensirikul, Pakamas
, p. 3626 - 3631 (2007/10/03)
5-Phenylisothiazole undergoes phototransposition via the electrocyclic ring closure-heteroatom migration pathway and by the N2-C3 interchange reaction pathway. The latter route is enhanced by the addition of triethylamine (TEA) to the reaction medium and by increasing the polarity of the solvent. In addition to phototransposition, 5-phenylisothiazole also undergoes photocleavage to 2-cyano-1-phenylethenethiol which was trapped by reaction with benzyl bromide to yield 2-cyano-1-phenylethen-1-ylbenzyl thioether. 3-Phenylisothiazole also phototransposes by both reaction pathways, but the product distribution is not affected by the addition of TEA or by changing the solvent polarity.
Phototransposition Chemistry of 4-Substituted Isothiazoles. The P4 Permutation Pathway
Pavlik, James W.,Tongcharoensirikul, Pakamas,French, Kathleen M.
, p. 5592 - 5603 (2007/10/03)
Upon irradiation in the presence of a small quantity of base, 4-substituted isothiazoles undergo photocleavage to yield substituted cyanosulfides, which can be trapped as their benzyl thioether derivatives, and substituted isocyanosulfides. Both products are suggested to arise via initial photocleavage of the sulfur-nitrogen bond, resulting in the formation of a substituted β-thioformylvinyl nitrene, which can rearrange to the observed cyanosulfide, or cyclize to an undetected thioformylazirine. Deprotonation of the azirine leads directly to the isocyanosulfide. The plight of the isocyanosulfide depends on the C-4 substituent. If the substituent is aromatic, the isocyanosulfide is reprotonated at the isocyanide carbon and spontaneously cyclizes to a 4-substituted thiazole, the observed transposition product. If the substituent is not aromatic, the isocyanosulfide is reprotonated at sulfur and the resulting species has a higher energy barrier to cyclization. In these cases, the isocyanosulfides can be observed spectroscopically and can be trapped as their N-formylaminobenzyl thioether derivatives.
Deamination of 2-aminothiazoles and 3-amino-1,2,4-triazines with nitric oxide in the presence of a catalytic amount of oxygen
Itoh, Takashi,Matsuya, Yuji,Nagata, Kazuhiro,Ohsawa, Akio
, p. 1547 - 1549 (2007/10/03)
2-Aminothiazoles, 2-aminobenzazoles, and 3-amino-1,2,4-triazines were deaminated using nitric oxide (NO) in the presence of a catalytic amount of oxygen to afford corresponding unsubstituted heterocycles in good yields.
