Lithium 1-alkynethiolates, generated by a base-induced ring cleavage of 4-substituted 1,2,3-thiadiazoles, were efficiently converted into the corresponding sulfenate salts by mild oxidation using an N-sulfonyloxaziridine derived from pinacolone. In situ S-alkylation with alkyl halides led to α,β-acetylenic sulfoxides.
Preparation of 2<i>H</i>-spiro[benzo[<i>d</i>]isothiazole-3,3′-pyrazole]-1, 1-dioxide-2′(4′<i>H</i>)-carboxylates from dilithiated<i>C</i>(α),<i>N</i>-carboalkoxyhydrazones and methyl 2-(aminosulfonyl)benzoate
作者:Anna C. Dawsey、Chandra Potter、John D. Knight、Zachary C. Kennedy、Ellyn A. Smith、Amanda M. Acevedo-Jake、Andrew J. Puciaty、Clyde R. Metz、Charles F. Beam、William T. Pennington、Donald G. VanDerveer
DOI:10.1002/jhet.50
日期:2009.3
A variety of substituted spiro(benzoisothiazole-pyrazoles) have been prepared by the condensation of dilithiated C(α),N-carboalkoxyhydrazones with lithiated methyl 2-(aminosulfonyl)benzoate followed by the cyclization of intermediates with acetic anhydride, which also resulted in spiro N-acetylated products when carbomethoxyhydrazones or carboethoxyhydrazones were used, and spiro NH products when
The reaction of 1,2,3-thiadiazoles with base. I. A new route to 1-alkynyl thioethers
作者:R. Raap、R. G. Micetich
DOI:10.1139/v68-179
日期:1968.4.1
unsubstituted in the 5-position, and a strong base such as an organolithium compound, sodamide, sodium methylsulfinyl carbanion, or potassium t-butoxide results in cleavage of the thiadiazole ring system with evolution of nitrogen and formation of alkalimetal alkynethiolate. Subsequent addition of an alkyl or acyl halide to the reaction mixture produces 1-alkynyl thioethers. 4-(5-Phenyl-1,2,3-thiadiazolyl)lithium
Synthesis and reactions of chloroazodienes. A new and general synthesis of pyridazines
作者:Michael S. South、Terri L. Jakuboski
DOI:10.1016/0040-4039(95)01128-5
日期:1995.8
base gives 4-chloroazodienes, which were found to combine with a variety of electron rich olefins to yield chloro-substituted tetrahydropyridazines. These chloroazodiene cyclizations are best characterized as inverse electron demand, 4+2 hetero Diels-Alder reactions that maintain a high degree of regio- and stereochemical control. The chloro-substituted tetrahydropyridazines that are formed give high yields
作者:Michael S. South、Terri L. Jakuboski、Mark D. Westmeyer、Daniel R. Dukesherer
DOI:10.1016/0040-4039(96)00020-2
日期:1996.2
The novelcyclizationreactions of the in-situ generated 1-carboxyethyl-3-phenyl-4,4-dichloroazodiene were found to give N-aminopyrroles and pyridazines when combined with acyclic enamines, Table 1. However, reactions with cyclic enamines gave the N-aminopyrroles, pyridazines, a dihydropyridazine as products as well as the non-cyclized enamine intermediates, Table 2. The enamines 10c and 11c could