1122-25-4Relevant articles and documents
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Spencer,T.A. et al.
, p. 5727 - 5729 (1967)
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Base-promoted ring expansion of 3-aminopyrimidine-2-thiones into 1,2,4-triazepine-3-thiones
Fesenko, Anastasia A.,Shutalev, Anatoly D.
supporting information, p. 2560 - 2573 (2016/04/26)
A base-promoted ring expansion of 3-amino-4-hydroxyhexahydropyrimidine-2-thiones into 2,4,5,6-tetrahydro-3H-1,2,4-triazepine-3-thiones has been developed. Experimental data and DFT calculations showed that the reaction proceeded through fast formation of intermediate acyclic isomers of pyrimidines followed by their slow cyclization into triazepines. The starting hydroxypyrimidines were prepared by reaction of α,β-unsaturated ketones or β-alkoxy ketones with HNCS followed by treatment of the obtained β-isothiocyanato ketones with hydrazine. Triazepine-3-thiones were transformed into their 3-oxo analogs by oxidation with H2O2 under basic conditions.
NEW DEVELOPMENTS OF THE WHARTON TRANSPOSITION
Dupuy, C.,Luche, J. L.
, p. 3437 - 3444 (2007/10/02)
The synthetically useful Wharton transposition can be improved by using a more adequate procedure in the critical step of the intermediate α-epoxyhydrazone cleavage.Either for stable hydrazones or unstable ones, the yield of the transposed allylic alcohol is increased by treatment under anhydrous conditions with highly basic reagents (KDA in the former case, NEt3 in the latter).
α-Haloalkanesulfonyl Bromides in Organic Synthesis. 3. α-Alkylidene Ketones and 1,3-Oxathiole 3,3-Dioxides from Trimethylsilyl Enol Ethers
Block, Eric,Aslam, Mohammad,Iyer, Rajeshwari,Hutchinson, John
, p. 3664 - 3666 (2007/10/02)
α-Alkylidene ketones and 1,3-oxathiole 3,3-dioxides can be conveniently prepared by treatment of trimethylsilyl enol ethers with α-haloalkanesulfonyl bromides followed by an amine base such as 1,5-diazabicyclonon-5-ene (DBN).
