Ignacio H. Sanchez

Sceletium (Aizoaceae) Alkaloids: Total Synthesis of Racemic Mesembranone, Mesembrenone, O-Methylsceletenone and O-Methyl Dihydrosceletenone

Abstract As a continuation of our synthetic studies2 regarding the Sceletium (Aizoaceae) alkaloids3 we decided to test the usefulness of the recently reported4 Arylacetonitrile Route when combined with the well-known5 endocyclic enamine pathway first enunciated by Curphey6, Stevens7 and Tahk8 in 1968.

Facile Synthesis of Alkyl 5-Alkoxy-3-Oxopentanoates

Abstract A facile synthesis of several alkyl 5-alkoxy-3-oxopentanoates, based on the reductive elimination of triphenylphosphine from the readily available alkyl 5-alkoxy-3-oxo-2-(triphenylphosphoranylide-ne) pentanoates, is described.

N-p-Toluenesulfonylpyrroles from 1,3-Dienes

Abstract 1,3-Dienes can be converted to N-p-toluenesulfonylpyrroles in two steps: 1) [4+2]-cycloaddition with N-sulfinyl-p-toluenesulfonamide and 2) conversion of the 3,6-dihydro-1,2-thiazine oxide adduct to a pyrrole using triethylamine-trimethylphosphite.

Facile Synthesis of 4-Carbethoxycyclohexanone

Abstract A facile decarboalkoxylative route to 4-carbethoxycyclohexanone (1) from the tricarbethoxy derivative 3 is described.

Sceletium (aizoaceae) alkaloids: total synthesis of racemic mesembranone, joubertinamine and epijoubertinamine

Abstract The total synthesis of the Sceletium alkaloids mesembranone, joubertinamine and epijoubertinamine via the intramolecular cyclization of an enone to a benzensulfo n amide grouping under the conditions of a dissolving metal reduction is described.

Improved formal total synthesis of tetrahydrometinoxocrinine

Abstract An improved, isomer-free synthesis of Tetrahydrometinoxocrinine ( 1 ) is described.

Application of the Cyanurate-Isocyanurate Rearrangement to Amine Synthesis: Preparation of 2-(2-Thienyl)ethylamine

Abstract This communication describes a new method for preparation of 2-(2-thienyl)ethylamine, an important pharmaceutical intermediate. The method is based on the O-to-N migration of an alkyl group via cyanurate-isocyanurate rearrangement.

Sceletium (Aizoaceae) Alkaloids : Short Total Synthesis of Racemic O-methyljoubertiamine by the Arylacetonitrile Route

Abstract Renewed synthetic interest in the mesembrane alkaloids3,4 has resulted from the recent characterization of several new bases found in various Southwest African Sceletium (Aizoaceae) species used in the elaboration of the pharmacollogicalPy interesting preparation known a8 “Channa” or “Kougoed”4. These include, amongst others, the seco-mesembrane alkaloids joubertiamine (Ia), dihydrojoubertiamine (11) and dehydrojoubertiamine (III)5.

2D NMR Studies of Octahydroindole Svstems

Abstract The 1H and 13C NMR resonances of title compounds were assigned by using 2D and decoupling techniques. The stereochemistry of ring fusion was identified by using, in particular, NOE and COSY 1H1H experiments. The low temperature COSY enables the evaluation of the relative populations (2:1) of N-acyl forms of isomeric octahydroindoles resolvable at −60°C.

Synthetic studies in the tetranorditerpene lactone series. I. The total synthesis of dihydro-8-epi-acrostalidic acid

Abstract The total synthesis of dihydro-8-epi-acrostalidic acid ( 8b ) and other related tetranorditerpene lactones are described.