Author pages are created from data sourced from our academic publisher partnerships and public sources.
Berberine and coptisine free bases
Abstract The free bases of protoberberine alkaloids berberine and coptisine and related compounds have been examined. The 1H and 13C NMR data of 8-hydroxy-7,8-dihydroberberine (2a),… Expand
Synthesis of the anti-HIV agent (-)-hyperolactone C by using oxonium ylide formation-rearrangement.
Starting from readily available (S)-styrene oxide an asymmetric synthesis is described of the naturally occurring anti-HIV spirolactone (-)-hyperolactone C, which possesses adjacent fully substituted… Expand
Fused Tetracyclic Heterocycles by Thermally Initiated Intramolecular Criss-Cross Cycloaddition of 3-Substituted Homoallenylaldazines
A thermally initiated intramolecular criss-cross cycloaddition of 3-substituted symmetrical homoallenyl azines (5) was searched. Their cyclization led to interesting new fused heterocyclic systems… Expand
Molecular and Crystal Structures of Three Berberine Derivatives
- S. Man, M. Potáček, M. Nečas, Z. Ẑák, J. Dostal
- Molecules : A Journal of Synthetic Chemistry and…
- 30 April 2001
Berberine azide, berberine thiocyanate, and 8-cyano-8H-berberine were prepared from berberine chloride, a quaternary protoberberine alkaloid. The molecular and crystal structures of all compounds are… Expand
Rearrangement of fused tetracyclic heterocycles induced by alkyl halides and formation of a new type of ‘proton sponge’
Abstract Intramolecular criss-cross cycloaddition of 3-substituted symmetrical homoallenyl azines 2 by heating in xylene lead to interesting fused heterocyclic systems consisting of four… Expand
The Synthesis of Two Regioisomeric Aldehydes with a Tetrahydrobenzo[b]thiophene Scaffold and Their Application in Solvent-Free Intramolecular 1,3-Dipolar Cycloaddition Reactions
The paper describes the synthesis of two regioisomeric 2-amino-3-formyl- and 3-amino-2-formyl-substituted derivatives of tetrahydrobenzo[ b ]thiophene and their subsequent thermally initiated… Expand
A new and facile synthesis of methyl 3-amino-4,5,6,7-tetrahydrobenzo[b]thiophene-2-carboxylate
A four-step synthesis of methyl 3-amino-4,5,6,7-tetrahydrobenzo[b]thiophene-2-carboxylate from commercially available starting materials is presented.
Unexpected Heterocyclic Products from Cycloaddition Reactions of Nonsymmetrical Allenyl Aldoketazines with Substituted Alkynes
Thermally initiated cycloaddition reactions of nonsymmetrical allenyl azines 1 with alkynes or other dipolarophiles usually lead to compounds with three fused, five-membered heterocyclic rings. With… Expand
Dihydropyrrolo[1,2-b]pyrazoles: withasomnine and related compounds
In the paper we indicate the increasing importance of derivatives containing a dihydropyrrolo[1,2-b]pyrazole (DPP) core. We try to show our synthetic approach based on an improved Kulinkovich method… Expand
Cyclization of β-allenyloximes as a novel method for nitrone preparation
Two different procedures for β-allenyloxime cyclization are described. One leads to substituted 1-hydroxypyrrolidines and the other represents a new route to pyrroline-N-oxides.