Atanas P. Venkov

Synthesis of isoquinolines from 2-phenylethylamines, amides, nitriles and carboxylic acids in polyphosphoric acid

Abstract A convenient one pot synthesis of 1-. 1.3-substituted 3.4-dihydroisoquinolines 5. enamines 10 and 3-oxo-2,3-dihydroisoquinolines 18 as well as of enamides 22 of isoquinoline from 2-phenyl-. 1,2-diphenylethylamines, phenylacetamides, phenylacetonitriles, N-acylphenylethyl-amines and carboxylic acids in nonaqueous media has been accomplished.

Synthesis of 3,4-dihydroisoquinolines, 2-alkyl(Acyl)-1(2H)-3,4-dihydroisoquinolinones, 2-alkyl-1(2H)-isoquinolinones and 1-alkyl-2(2H)-quinolinones by oxidation with potassium permanganate

Abstract Synthesis of 3,4-dihydroisoquinolines 2,2-alkyl- 6 and 2-acyl-3,4-dihydro -1(2H)-isoquinolinones 9 , 2-alkyl-1(2H)- isoquinolinones 14 , N-alkyl-3,4-dihydro-2(2H)-quinolinones 16 and N-alkyl-2(2H)-quinolinones 19 by oxidation of 1,2,3,4-tetrahydroisoquinolines 1, N-alkyl (acyl)iminium salts of 3,4-dihydroisoquinolines 5,8 and isoquinoline 13 as well as of N-alkyl ammonium salts of tetrahydroquinoline 15 and quinoline 18 with potassium permanganate is described.

An alumina catalyzed addition of secondary amines to exocyclic α,β-unsaturated ketones

Abstract A Michael addition of secondary amines to exocyclic α,β-unsaturated ketones has been achieved in excellent yield in the presence of alumina. In the absence of alumina, the reaction does not proceed or takes place in low yield with many side products after a long reaction time.

Synthesis of 1-Phenyl-2-acyl-tetrahydroisoquinolines by Intermolecular α-Amidoalkylation Reaction

Abstract 1-Phenyl-2-acyl-tetrahydroisoquinolines are obtained by an intermolecular α-amidoalkylation reaction of aromatics 4 with the adducts 3 of 3,4-dihydroiso-quinolines and acyl chlorides.

1,1-Disubstituted Tetrahydroisoquinolines from Enaminones via Pictet–Spengler Reaction

Abstract Enaminones, prepared by condensation of homoveratrylamine with 1,3-dicarbonyl compounds, undergo intramolecular cyclization in acidic media to afford 1,1-disubstituted tetrahydroisoquinolines in good yields. Further modification of the title compounds is demonstrated.

Application of the Intermolecular α-Amido-alkylation Reaction for the Synthesis of Tertiary Amides and 1-Substituted 2-Acyltetrahydroiso-Quinolines. Synthesis of (±)-Carnegine

Abstract Adducts 4 of Schiff bases and 3,4-dihydroisoquinolines with acyl chlorides react with Grignard reagents 5 in an intermolecular α-amidoalkylation reaction to the corresponding tertiary amides or 1-substituted 2-acyltetrahydroisoquinolines.

Synthesis of Some Novel 11b-Substituted Pyrimido(6,1-a)- isoquinoline Derivatives

A series of novel 11b-substituted 1,6,7,11b-tetrahydropyrimido[6,1-a]- isoquinoline-2,4-diones and 4-thioxo-1,3,4,6,7,11b-hexahydropyrimido[6,1-a]isoquinolin-2- ones were synthesized, utilizing two alternative strategies for ring closure of tetrahydroisoquinoline intermediates obtained from N-phenethyl enaminones.

Synthesis Of 2-Acyltetrahydro-β-Carbolines By An Intramolecular α-Amidoalkylation Reaction

Abstract 2-Acyltetrahydro-β-carbolines 7 have been obtained by cyclization of adducts 5 from imines 3 of tryptamine 1 and aldehydes 2 with acyl chlorides 4 as a result of an intramolecular a-amidoalkylation reaction in the presence of bases as N,N-dimethylaniline or Et3N.

The Application of Phase-Transfer Catalyzed Version of Atherton-Todd Reaction to Sulfonamides

Abstract A number of sulfonylphosphoramidates have been prepared by phase-transfer catalyzed version of Atherton-Todd reaction.

Sodium cyanoborohydride: a reagent for selective reduction of the oxazolidine ring of C20-diterpenoid alkaloids

Abstract A very selective reduction of the oxazolidine ring of C 20 -diterpenoid alkaloid derivatives in the presence of other functional groups, e.g., an α,β unsaturated ketone or a simple ketone, has been achieved in almost quantitative yield using sodium cyanoborohydride.