39208-34-9Relevant academic research and scientific papers
Environment-friendly and efficient synthesis of 2-aminobenzo-xazoles and 2-aminobenzothiazoles catalyzed by: Vitreoscilla hemoglobin incorporating a cobalt porphyrin cofactor
Li, Fengxi,Li, Zhengqiang,Su, Jiali,Wang, Chunyu,Wang, Ciduo,Wang, Lei,Xu, Yaning,Zhao, Nan
, p. 8047 - 8052 (2021/11/01)
In this study, an environment-friendly and efficient artificial Vitreoscilla hemoglobin (VHb) for the synthesis of 2-aminobenzoxazoles and 2-aminobenzothiazoles has been reported. We demonstrate an expression-based porphyrin substitution strategy to produce VHb containing cobalt porphyrin instead of native hemin, which can catalyze the oxidative cyclization of corresponding 2-aminobenzoxazoles and 2-aminobenthiazoles with up to 97% yield and 4850 catalytic turnovers in water under aerobic conditions. Hence, we provide a green and mild method for the synthesis of 2-aminobenzoxazoles and 2-aminobenzothiazoles. In addition, we indicate the value of porphyrin ligand substitution as a strategy to tune and enhance the catalytic properties of hemoproteins in non-natural reactions.
Iodide catalyzed synthesis of 2-aminobenzoxazoles via oxidative cyclodesulfurization of phenolic thioureas with hydrogen peroxide
Yadav, Vinod K.,Srivastava, Vishnu P.,Yadav, Lal Dhar S.
, p. 252 - 255 (2017/12/26)
A convenient and efficient oxidative cyclodesulfurization of o-phenolic thioureas to 2-aminobenzoxazoles employing TBAI (tetrabutylammonium iodide)/H2O2 catalyst/reagent system is reported. The protocol utilizes and offers a number o
Visible-light-promoted cyclodesulfurization of phenolic thioureas: An organophotoredox catalytic approach to 2-aminobenzoxazoles
Yadav, Vinod K.,Srivastava, Vishnu P.,Yadav, Lal Dhar S.
, p. 155 - 158 (2015/12/24)
A facile and efficient one-pot operation for the photo-oxidative cyclodesulfurization of o-phenolic thioureas to afford 2-aminobenzoxazoles is reported. The protocol could be executed under visible light irradiation employing eosin Y as an organophotoredo
A new NBS/oxone promoted one pot cascade synthesis of 2-aminobenzimidazoles/2-aminobenzoxazoles: A facile approach
Daswani, Ujla,Dubey, Nitin,Sharma, Pratibha,Kumar, Ashok
supporting information, p. 8093 - 8099 (2016/09/12)
A new strategy for the synthesis of 2-aminobenzimidazoles via a reaction of α-halogenated cyclohexanone with guanidine is reported. It provides a facile N-bromosuccinimide (NBS) mediated transition metal free, sustainable path for the synthesis of 2-substituted azoles. NBS along with the oxone promotes in situ halogenation of cyclohexanone, which in turn, when allowed to react with guanidine, afforded 2-aminobenzimidazoles (2-ABI). This eco-friendly protocol provides a competent laboratory synthesis method associated with significant advantages such as greater selectivity, cost-efficiency, mild reaction conditions, absence of chromatographic purification, clean reaction profile, and a simple work-up procedure to furnish high yields. The structures of all the synthesized compounds were confirmed on the basis of IR, 1H and 13C NMR, mass spectrometry, and elemental analyses data. In addition, we have also extended the scope of this strategy for obtaining 2-amino substituted benzoxazoles.
Dithiocarbamate promoted practical synthesis of N-Aryl-2-aminobenzazoles: Synthesis of novel Aurora-A kinase inhibitor
Katari, Naresh Kumar,Venkatanarayana,Srinivas, Kummari
, p. 447 - 453 (2015/05/20)
Various N-aryl-2-aminobenzoxazoles and N-aryl-2-aminobenzothiazoles were synthesized from o-aminophenol and o-aminothiophenol, respectively, mediated by dithiocarbamate in one step. The salient features of this method include mild reaction condition, high
An economically and environmentally sustainable synthesis of 2-aminobenzothiazoles and 2-aminobenzoxazoles promoted by water
Zhang, Xinying,Jia, Xuefei,Wang, Jianji,Fan, Xuesen
supporting information; experimental part, p. 413 - 418 (2011/04/16)
Tandem reactions of isothiocyanates (1) with 2-aminothiophenols (2), or isothiocyanates (1) with 2-aminophenols (4), were carried out rapidly and efficiently in water. A significant rate acceleration of the reaction between 1a and 2a in water compared wit
One-pot synthesis of five and six membered N, O, S-heterocycles using a ditribromide reagent
Yella, Ramesh,Patel, Bhisma K.
experimental part, p. 754 - 763 (2010/11/03)
In a one-pot procedure, bromine less brominating reagent 1,1′-(ethane-1,2-diyl)dipyridinium bistribromide (EDPBT) has been utilized as an efficient desulfurizing agent for the construction of a library of heterocycles containing N, O, and S starting from aryl/alkyl isothiocyanates. In this approach, aryl/alkyl isothiocyanate reacts with o-phenylenediamine (o-PD), o-aminophenol, and o-aminothiophenol to form their monothiourea which on desulfurization with EDPBT led to the formation of corresponding 2-aminobenzimidazoles, 2-aminobenzoxazoles, and 2-aminobenzothiazoles, respectively. An interesting regioselectivity was observed for unsymmetrical thiourea having a naphthyl moiety on the one side and an ortho amino or an ortho hydroxy phenyl group on the other side giving a completely different product which is mainly dependent on the nature of the nucleophiles (-OH or -NH 2). Further, the bis-thioureas resulted from the aliphatic 1,2-diamine with 2 equiv of aryl isothiocyanates on treatment with EDPBT gave imidazolidenecarbothioamides, whereas bis-thioureas resulted from aromatic 1,2-diamine yielded benzimidazoles with concurrent expulsion of an isothiocyanate unit. This method is simple and applied to various substrates which are amenable to bromination that reveals the desulfurizing ability of EDPBT predominating over its brominating ability. Finally, the spent reagent EDPDB can be recovered, regenerated, and reused without any loss of activity.
Desulfurization mediated by hypervalent iodine(III): A novel strategy for the construction of heterocycles
Ghosh, Harisadhan,Yella, Ramesh,Nath, Jayashree,Patel, Bhisma K.
scheme or table, p. 6189 - 6196 (2009/05/27)
The desulfurization ability of diacetoxyiodobenzene (DIB) has been explored in the preparation of isothiocyanates from the corresponding dithiocarbamate salts. The in situ generated isothiocyanates reacted with o-phenylenediamine and o-aminophenol to form monothioureas, which, on treatment with a further equivalent of DIB in one pot, gave benzimidazoles and aminobenzoxazoles, respectively. Aliphatic 1,2-diamines on reaction with 2 equiv. of isothiocyanate followed by treatment with DIB gave imidazolidenecarbothioamides, whereas the treatment of aromatic 1,2-diaminebis(thioureas) yielded benzimidazoles with the concurrent formation of isothiocyanate. The driving force for the formation of the latter is the aromatization of the product. The use of DIB makes these methods simpler and more efficient, giving high yields of the desired products in one pot. Wiley-VCH Verlag GmbH & Co. KGaA, 2008.
