Hydrazones sulfonylhydrazones

N2O2SC a-Diazosulfones a-Ketosulfone hydrazones Monosulfonylcarbodimides Sulfonylamidines Sulfonic acid amidines 5 N-Sulfonylformamidines 20 N -Sul fony Icyanamides Sulfonylformaldehyde hydrazones Sulfonylhydrazones Thiourea S-dioxides... 

A disadvantage of this method of synthesis is that unless the conditions are carefully controlled, complete oxidation of the bis hydrazone occurs, the product being an acetylene. This problem can normally be avoided by using bis toluene-p-sulfonylhydrazones. These are... 

A variation on the thermal reactions of diazo compounds with alkenes is the decomposition of salts of sulfonylhydrazones. This procedure, known as the BamfoTd-Stevens reaction, is believed to occur via the formation of diazo compounds. Subsequent 1,2-hydrogen shifts generally lead to the formation of alkenes as the final products. Cyclopropanes may also be formed as the result of intramolecular 1,3-C—H insertion reactions or when the original hydrazone substrate contains a remote alkenic group as a site for intramolecular cyclopropanation.10... 

Nitro-phenyl)-l -phenyl- E16a, 596 (Hamstoff-Umlager.) 2-(4-Nitro-phenyl)-l -phenyl- X/2, 713 E16a, 609 (Hydrazon-Red.) Naphthalin l-Diazo-4,4-dimethyl-6-nitro-l,4-dihydro- El4b, 1037 (Sulfonylhydrazon/NaO —R A) Propansaure 2-Diazo-3-(3-indolyl)- -methylester E14b, 1103 (Amin + R —O—NO)... 

Ketone toluene-p-sulfonylhydrazones of type (189) function as a convenient source of vinyllithium reagents (190) the latter are obtained by treatment of the hydrazones (189) with butyllithium (two equivalents) in a suitable solvent, e.g. ether or hexane (Scheme 77). 

Most tosylhydrazone sodium salts could be usually Isolated from the reaction of the corresponding tosylhydrazones with sodium methoxide. However, a number of more functionalized hydrazone sodium salts, such as those derived from alkenyl aryl (25) sulfonyUiydrazones, ketone sulfonylhydrazones, and trimethylsi-lylacrolein sulfonylhydrazones, could not be isolated and an in situ salt generation procedure using NaHMDS was developed. A mixture of the desired hydrazones and NaHMDS was stirred at —78 °C then concentrated down before the addition of rhodium... 

Lam and Raghavendra have also highlighted the synthesis of 1,2,3-triazoles through an intramolecular cyclization of a diazo intermediate that was generated from the Bamford-Stevens reaction between a tosyl hydrazone and abase. Polystyrene sulfonyl hydrazide 74 was treated with 1,1-dichloroacetone in THF to yield polymer-bound a-dichloro carbonyl sulfonylhydrazone 75 (Scheme 12.19). Alternative reaction of 74 with 1,1,1-trichloroace-taldehyde and pyridine derivatives yielded resin 76 and 77. When treated with excess amine,... 

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