- Stereoselective synthesis and characterization of monocyclic cis-β-lactams containing 5-methyl-1,3,4-thiadiazole-2-thiol moiety
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This article describes the stereoselective synthesis of monocyclic cis-β-lactams. The 2-(4-chlorophenoxy)-acetic acid or 2-phenoxy-acetic acid with a carboxylic acid activator 2-ethoxy carbonyl DCPN generate ketene in situ, which reacts with imines derived from substituted tetralone carbaldehyde yielded monocyclic cis-β-lactams having 5-methyl-1,3,4-thiadiazole-2-thiol moiety through [2+2] cyclo-addition reaction (Staudinger reaction). All structures of cis-β-lactams were elucidated by a spectral technique like FT-IR, 1H and 13C NMR spectra, HRMS, and single X-ray crystallography. The cis configuration of the β-lactams was determined based on coupling constant (J) value using 1H NMR for hydrogens H-3 and H-4 of the β-lactams ring. This work presents the synthesis of β-lactams more simply with high yields. The products were simply purified by crystallization technique.
- Singh, Vedeshwar N.,Sharma, Sitaram
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- Synthesis of organic carbonates with alkyl/aryl 4,5-dichloro-6-oxopyridazine-1(6H)-carboxylates and ROH/AlCl3under ambient condition
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We demonstrated the synthesis of organic carbonates using alkyl/aryl 4,5-dichloro-6-oxopyridazine-1(6H)-carboxylates and alcohol in the presence of aluminum chloride. Alkyl/aryl 4,5-dichloro-6-oxopyridazine-1(6H)-carboxylates were reacted with alcohol in the presence of AlCl3 in toluene at room temperature to afford the corresponding unsymmetric and symmetric organic carbonates in good to excellent yields. These are efficient and convenient processes. Alkyl/aryl 4,5-dichloro-6-oxopyridazine-1(6H)-carboxylates are solid, stable and non-toxic CO2/CO2R(Ar) source. It is noteworthy that the reaction is carry out under an ambient and acidic conditions, the easy-to prepare and readily available starting materials and the quantitative isolation of reusable 4,5-dichloropyridazin-3(2H)-one.
- Sung, Gi Hyeon,Bo, Ram Kim,Ryu, Ki Eun,Kim, Jeum-Jong,Yoon, Yong-Jin
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p. 2758 - 2764
(2015/04/22)
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