Le Anh Nguyen, Supasorn Phaenok, Duc Long Le, Thi Thu Tram Nguyen, Quoc Anh Ngo*, and Thanh Binh Nguyen*
Org. Lett. 2023, 25, 5145-5150.
Abstract. As frequently encountered byproducts of isocyanate chemistry, hydrogen sulfide and related sulfur containing compounds should be treated in a safe way to lower their adverse health and environmental effects, especially in large scale syntheses. As a proof of concept, we report herein an example of in situ recycling of sulfur byproduct to reductant in the synthesis of bioactive 2-aminobenzoxazoles 3. Using an Fe/S catalytic system, this heterocyclic scaffold could be obtained from o-nitrophenols 1 with isothiocyates 2 via direct redox condensation consisting of reduction of the nitro group of 1 by the sulfur moiety of 2.
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Bich Ngoc Nguyen, Minh Hieu Tran, Thai Thanh Thu Bui, Dinh Hung Mac*, Van Phong Pham*, Pascal Retailleau, and Thanh Binh Nguyen*
J. Org. Chem. 2023, 88, 15, 11197–11204
Abstract.
Elemental sulfur and DABCO were found to be an excellent combination to
promote a one-pot cascade of condensation-oxidative cyclization of
chalcones and unsubstituted cyanoacetamide in DMSO to provide
3-cyanopyrid-2-ones.
xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxHoang Yen Nguyen, Thi Minh Chau Tran, Van Ha Nguyen, Pascal Retailleau, Dinh Hung Mac* and Thanh Binh Nguyen*
Org. Biomol. Chem. 2023, 21, 503-507.
Abstract. 1-Anilinonaphtho[2,1-b]thiophenes could be conveniently synthesized from a three-component reaction of 1-acetonaphthones with anilines and elemental sulfur under catalyst-free simple heating conditions.
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Thanh Binh Nguyen* and Pascal Retailleau
Chem. Commun. 2022, 58, 13333-13336.
Abstract. Thieno[3,4-b]thiophene cores could be conveniently obtained via one-pot sulfurative tetramerization of acetophenones using a ternary system comprised of elemental sulfur, a base and DMSO under simple heating conditions. The structure of the products was verified by X-ray crystallography.
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Thi Thu Tram Nguyen, Viet Dung Duong,Thi Ngoc Nga Pham, Quoc Thanh Duong and Thanh Binh Nguyen*
Org. Biomol. Chem. 2022, 20, 8054-8058.
Abstract.The elemental sulfur–DMSO couple was found to efficiently promote the oxidative coupling of active methylhetarenes with amines to yield amides under simple heating conditions. When 2-methylquinoline was used as the methylhetarene component, the formation of the expected 2-quinolinecarboxamides from anilines could be efficiently catalyzed by iron, nickel and cobalt salts. The method displayed good functional group tolerance and was applicable to aromatic, heteroaromatic and aliphatic amines. Other substrates such as phenylacetic acid, dibenzyl disulfide, and benzylamine could act as competent partners in place of methylhetarenes.
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Thanh Binh Nguyen,* and Pascal Retailleau
Org. Lett. 2022, 23, 6676–6680.
DOI:10.1021/acs.orglett.2c02736
Abstract.2-Naphthols 1were found to react with aryl isothiocyanates 2 to provide 2-iminonaphtho-1,3-oxathioles 3 in the presence of DABCO as a catalyst. When elemental sulfur was used, moderate to good yields of 3 could be achieved from a nearly equimolar mixture of two starting materials 1 and 2. Products 3 could also be formed in the absence of sulfur or an external oxidant. In the latter case, an additional equivalent of 2 was found to act as a dehydrogenating agent.
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Thanh Binh Nguyen,* Hung Dinh Mac,* Thi Minh Chau Tran, Bich Ngoc Nguyen and Hai Thuong Cao
Org. Biomol. Chem. 2022, 20, 7226-7231.
DOI: 10.1039/D2OB01343F
Abstract.3-Arylquinoxaline-2-thiones were conveniently synthesized via three-component oxidative condensation of acetophenones with o-phenylenediamines and sulfur in DMSO in the presence of piperidine as a catalyst. The products could be readily isolated from the reaction mixture by simple precipitation and washing with methanol. This set of reaction conditions applied to higher homologs of acetophenones as well as benzyl phenyl ketones led to 2,3-di-C-substituted quinoxalines. Further functionalization of 3-phenylquinoxaline-2-thione via reaction on the thione group could be readily performed to provide quinoxaline derivatives in good yields.
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Le Anh Nguyen, Thi Thu Tram Nguyen, Quoc Anh Ngo,* Thanh Binh Nguyen*
Adv. Synth. Catal. 2022, 364, 2748-2752.
DOI: 10.1002/adsc.202200527
Nguyen, L. A.; Nguyen, T. T. T.; Ngo, Q. A.; Nguyen, T. B. Adv. Synth. Catal. 2022, 364, 2748-2752.
Abstract. While elemental sulfur has been largely used as oxidant or sulfurating agent, its role as a catalyst has not been developed. We report here its catalytic activity in the oxidative condensation of o-phenylenediamines with acetophenones in DMSO to provide quinoxalines. The method was also extended to α-tetralones, propiophenones (R=Me) as well as higher homologues (R=Et, n-Pr) in place of acetophenones, leading to a wide range of naphthoquinoxalines and 3-substituted 2-arylquinoxalines.
xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Nang Duy Lai, Thu Trang Nguyen, Nhu Ngan Ha Nguyen, Pascal Retailleau, Dinh Hung Mac* and Thanh Binh Nguyen*
DOI: 10.1039/D2QO00526C
Org. Chem. Front. 2022, 9, 3163-3168.Abstract. 3-Cyanothiophene is an important heterocyclic scaffold in bioorganic and
medicinal chemistry as a useful synthetic intermediate as well as in
materials science as a privileged motif for photovoltaic development.
Herein, we report our unexpected results on the formation of
3-cyanothiophene derivatives as the major products via a
three-component reaction of chalcones, benzoylacetonitriles and
elemental sulfur along with the minor products 2-aminothiophenes. The
ratios between these two thiophene products is 4 : 3 and could be varied
by simply changing the promoting base as well as its stoichiometric
ratio. The method was successfully extended to benzoylacetate in place
of benzoylacetonitrile to provide thiophene-3-carboxylates.
xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Thanh Binh Nguyen*
Nguyen, T. B. Clean Technol. 2022, 4, 234-238.
DOI: 10.3390/cleantechnol4020013
Abstract. Elemental sulfur (S8) was found to react very rapidly (<1
min) with a stoichiometric amount of triphenylphosphine at rt in
sufficient amount of solvent (0.2–0.5 mL of solvent/1 mmol of PPh3).
Compared to the previously described methods, the present procedure
constitute excellent access to triphenylphosphine sulfide.
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Tan Sang Truong, Pascal Retailleau, Thanh Binh Nguyen*
Asian J. Org. Chem. 2022,11, e202100751
DOI: 10.1002/ajoc.202100751
Truong, T. T.; Retailleau, P.; Nguyen, T. B. Asian J. Org. Chem. 2022, 11, e202100751
Abstract.
TFA/DMSO combination was found to efficiently promote the
cross-dehydrogenative coupling of a wide range of hetaryl thiols with
indole derivatives, leading to 3-(hetarylsulfenyl)indoles in good-to
excellent yields under mild heating conditions. Two-fold
hetarylsulfenylation of indoles in 2- and 3- positions could be
conveniently achieved by simply adapting molar ratio of the starting
materials.
xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Thanh Binh Nguyen,* and Pascal Retailleau
Org. Lett. 2021, 23, 5344-5348.
DOI:10.1021/acs.orglett.1c01653
Nguyen, T. B.; Retailleau, P. Org. Lett. 2021, 23, 5344-5348.
Abstract. A convenient synthesis of thiazole-2-thiones was developed based on base-catalyzed three-component reac-tions between chalcones, isothiocyanates and elemental sulfur.
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Thanh Binh Nguyen,* Dinh Hung Mac,* and Pascal Retailleau
J. Org. Chem. 2021, 86, 9418-9427.
DOI: 10.1021/acs.joc.1c00740
Nguyen, T. B.; Mac, D. H.; Retailleau, P. J. Org. Chem. 2021, 86, 9418-9427.
Abstract. While Gewald reaction was well known for more than haft a century as an excellent method providing bioactive 2-aminothiophenes from reactions of α-cyanoacetates and carbonyl compounds and elemental sulfur, its application to dibenzoylmethanes as the carbonyl substrates was however unknown and experimentally proven unsuccessful. We proposed here a convenient approach to such series of compounds by a DABCO catalyzed, one-pot, two-step, three-component reaction of α-cyanoacetate with chalcones and elemental sulfur. This catalytic strategy is highlighted by its excellent atom/step efficiency and high degree of structural diversification by simply choosing the suitable starting chalcones, which are unarguably much more readily available than dibenzoylmethanes.
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Le Anh Nguyen, Thi Thu Tram Nguyen, Quoc Anh Ngo,* Thanh Binh Nguyen*
Org. Biomol. Chem. 2021, 19, 6015-6020.
DOI:10.1039/D1OB00976A
Nguyen, L. A.; Nguyen, T. T. T.; Ngo, Q. A.; Nguyen, T. B. Org. Biomol. Chem. 2021, 19, 6015-6020.
Abstract. An Fe/S catalyst generated in situ from FeCl2·4H2O and elemental sulfur S8 in the presence of a tertiary amine as a base was found to catalyze efficiently a 6e− redox condensation of o-nitrophenols
with acetophenones and methylquinolines. The condensed products
2-benzoylbenzoxazoles and 2-quinolylbenzoxazoles were obtained in
reasonable yields with water as the only byproduct at a temperature as
low as 80 °C.
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