A set of novel series of 1,3,4-thiadiazolyl-sulfanyl-4,5-dihydropyridazin-3(2H)-ones with anticipated antimicrobial activity has been synthesized. The synthetic protocol of the targeted compounds was accomplished by treating β-aroylacrylic acid 1 with 5-amino-1,3,4-thiadiazole-2-thiol (2) to afford the thia-Michael adduct 3. Afterwards, the obtained thia-Michael adduct 3 was cyclized to 4,5-dihydropyridazin-3(2H)-ones 4a-d and the non-cyclized product hydrazone 5 by using different hydrazines. Moreover, adduct 3 was reacted with esters like diethyl malonate and ethyl acetoacetate affording 1,3,4-thiadiazolobutanamides 6a, b. Furthermore, the concurrent reaction of later butamides 6a, b with the hydrazine derivatives furnished thiadiazolopyridazin-3(2H)-ones 7a-d, 8, and butanoic acid 9.
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http://dx.doi.org/10.1248/cpb.c17-00918 | DOI Listing |
Org Biomol Chem
December 2024
Institute of Organic Chemistry, Catalysis and Petrochemistry, Slovak University of Technology, Radlinského 9, 812 37 Bratislava, Slovakia.
J Org Chem
May 2024
Department of Chemistry, School of Chemical Sciences and Pharmacy, Central University of Rajasthan, NH-8, Bandarsindri District, Ajmer, Rajasthan 305817, India.
The reaction of Morita-Baylis-Hillman ketones with 2-aminothiophenol mediated by CsCO results in an oxidative cyclization to 2,2-disubstituted dihydro-1,4-benzothiazines, with the structure of the product indicating the occurrence of an aza-Michael addition along the pathway. In contrast, in the absence of a base, the parent compounds interact to produce a thia-Michael adduct instead. A deeper mechanistic study improved our understanding of the apparent contradiction and provided insight into the base-dependent switch in reactivity.
View Article and Find Full Text PDFMolecules
January 2024
Department of Industrial Chemistry 'Toso Montanari', Alma Mater Studiorum-Università di Bologna, Via Piero Gobetti 85, 40129 Bologna, Italy.
Juglone, a quinonic compound present in walnut extracts, was proposed as a restoring agent for hair keratin treated with permanent or discoloration processes. The proposed mechanism of restoration by juglone involves the formation of a Michael adduct between the quinone and the thiol moieties of cysteine residues. To this purpose, the first part of the present paper involved the spectroscopic study of the product of the reaction between juglone and N-acetyl-L-cysteine as a model compound.
View Article and Find Full Text PDFChem Commun (Camb)
December 2023
Graduate School of Pharmaceutical Sciences, Tohoku University, 6-3 Aoba, Aramaki, Aoba-ku, Sendai, 980-8578, Japan.
Ratiometric Raman analysis of reversible thia-Michael reactions was achieved using α-cyanoacrylic acid (αCNA) derivatives. Among αCNAs, the smallest derivative, ThioRas (molecular weight: 167 g mol), and its glutathione adduct were simultaneously detected in various subcellular locations using Raman microscopy.
View Article and Find Full Text PDFOrg Biomol Chem
September 2023
Department of Chemistry and Center of Excellence for Innovation in Chemistry (PERCH-CIC), Faculty of Science, Mahidol University, Rama VI Road, Bangkok 10400, Thailand.
Base-catalyzed diastereodivergent thia-Michael addition of thiols to chiral β-trifluoromethyl-α,β-unsaturated -acylated oxazolidin-2-ones is reported. By tuning the base-catalyst (-PrNEt, DABCO, or P--Bu), a range of chiral thia-Michael adducts was synthesized in good yields with high diastereoselectivities. A plausible mechanism was proposed on the basis of the experimental results.
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