Showing papers by "Branko Stanovnik published in 1999"
57 citations
TL;DR: Methyl 2-(benzyloxycarbonyl)aimno-3-dimemylaminopropenoate (2) was prepared from methyl N-(bensyloxy carbonyl)-glycinate (1) and t-butoxybis(dimethylamino)methane, and used as a reagent for preparation of substituted 3-amino compounds 7, 8, 20, 36, 38 and 53-57 in yields better than 80% as discussed by the authors.
38 citations
TL;DR: In this paper, the rel-(4R,5R)-4-benzoylamino-5-phenyl-3-pyrazolidinone-1-azomethine imines 3a-g, were treated with sodium borohydride to give rel(4 R, 5R)-1-alkyl-4-Benzoyl-3,alkylamino,3,phenylalanine amides 5a-f.
18 citations
TL;DR: In this article, a cycloaddition of dimethyl acetylenedicarboxylate (3) to (1Z)-rel-(4R,5R)-1-aryl-methylidene-4-benzoylamino-5-phenyl-3-pyrazolidinone-1-azomethine imines is presented.
17 citations
TL;DR: In this article, 5-substituted (S)-tetrahydrofuran-2-ones (1a,b) and 3-acetylaminopyrrolidin-2 -ones (4c,d) were transformed in three steps, by treatment with tert-butoxybis(dimethylamino)methane (Bredereck's reagent), followed by nitrosation and stereoselective catalytic hydrogenation, into the corresponding (3S,5S)-3-actylamin
11 citations
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TL;DR: Methyl 2-(benzyloxycarbonyl)aimno-3-dimemylaminopropenoate (2) was prepared from methyl N-(bensyloxy carbonyl)-glycinate (1) and t-butoxybis(dimethylamino)methane, and used as a reagent for preparation of substituted 3-amino compounds 7, 8, 20, 36, 38 and 53-57 in yields better than 80%.
Abstract: Methyl 2-(benzyloxycarbonyl)aimno-3-dimemylaminopropenoate (2) was prepared from methyl N-(benzyloxycarbonyl)glycinate (1) and t-butoxybis(dimethylamino)methane, and used as a reagent for preparation of substituted 3-(benzyloxycarbonyl)amino-4H-quinolizin-4-ones 5 and 6, −2H-pyran-2-ones 17–19, −2H-1-benzopyran-2-ones 28–31, and -naphthopyrans 32–35, −2H-pyrano[3,2-c]pyridine-2,5-dione 46, -pyrano-[4,3-b]pyran-2,5-dione 47, -pyrano[3,2-c]benzopyran-2,5-dione 48, -pyrano[2,3-c]pyrazol-6-ones 49 and 50, -pyrano[2,3-d]pyrirnidin-7-ones 51 and 52 derivatives. In the reaction of 2 with 1,3-diketones trisubsti tuted pyrroles 14–16 were formed. Selective removal of benzyloxycarbonyl group was achieved by cat alytic transfer hydrogenation with Pd/C in the presence of cyclohexene to afford free 3-amino compounds 7, 8, 20, 36–38 and 53–57 in yields better than 80%.
2 citations
TL;DR: Methyl 2-benzoylamino-3-oxobutanoate (3) was prepared from hippuric acid (1) which was converted with N,N-dimethylacetamide and phosphorus oxychloride into 4-(1-dimethylaminoethylidene)-2-phenyl-5(4H)-oxazolone (2) followed by hydrolysis with hydrochloric acid in methanol.
Abstract: Methyl 2-benzoylamino-3-oxobutanoate (3) was prepared from hippuric acid (1) which was converted with N,N-dimethylacetamide and phosphorus oxychloride into 4-(1-dimethylaminoethylidene)-2-phenyl-5(4H)-oxazolone (2) followed by hydrolysis with hydrochloric acid in methanol. Compound 3 was treated with hydrazines 4 to give 4-benzoylamino-3-methyl-1H-pyrazol-5(2H)-one (6a) and its 1-substituted derivatives 6b-j. The corresponding hydrazones 5f, i, j were isolated as intermediates.
TL;DR: In this paper, the transformation of intermediates from methyl 2-(2,2-disubstituted-ethenyl)amino-3-dimethylaminopropenoates and sterically hindered heteroarylamines into methyl 1-heteroaryl-1H-imidazole-4-carboxylates was described.
Abstract: Transformations of intermediates 4, prepared from methyl 2-(2,2-disubstituted-ethenyl)amino-3-dimethylaminopropenoates 2 and sterically hindered heteroarylamines 3, into methyl 1-heteroaryl-1H-imidazole-4-carboxylates 7 are described.
TL;DR: In this article, a cycloaddition of dimethyl acetylenedicarboxylate (3) to (1Z)-rel-(4R,5R)-1-aryl-methylidene-4-benzoylamino-5-phenyl-3-pyrazolidinone-1-azomethine imines is presented.
Abstract: rel-(2R,3R)-N-Benzoylamino-6,7-bis(methoxycarbonyl)-2,3-dihydro-1-oxo-1H,5H-pyrazolot[1,2-a]-pyrazoles 5, accesible by cycloaddition of dimethyl acetylenedicarboxylate (3) to (1Z)-rel-(4R,5R)-1-aryl-methylidene-4-benzoylamino-5-phenyl-3-pyrazolidinone-1-azomethine imines 4, undergo oxidative ring cleavage with methanolic bromine giving rel-(2R,3R)-N-benzoyl-3-phenyl-3-[5-aryl-3,4-bis(methoxy-carbonyl)pyrazolyl-1]alanine methyl esters 6 as products.
TL;DR: In this paper, 5-substituted (S)-tetrahydrofuran-2-ones (1a,b) and 3-acetylaminopyrrolidin-2 -ones (4c,d) were transformed in three steps, by treatment with tert-butoxybis(dimethylamino)methane (Bredereck's reagent), followed by nitrosation and stereoselective catalytic hydrogenation, into the corresponding (3S,5S)-3-actylamin
Abstract: 5-Substituted (S)-tetrahydrofuran-2-ones (1a,b) and (S)-pyrrolidin-2-ones (1c,d) were transformed in three steps, by treatment with tert-butoxybis(dimethylamino)methane (Bredereck's reagent), followed by nitrosation and stereoselective catalytic hydrogenation, into the corresponding 5-substituted (3S,5S)-3-acetylaminotetrahydrofuran-2-ones (4a,b) and (3S,5S)-3-acetylaminopyrrolidin-2-ones (4c,d).
TL;DR: In this article, the rel-(4R,5R)-4-benzoylamino-5-phenyl-3-pyrazolidinone-1-azomethine imines 3a-g, were treated with sodium borohydride to give rel(4 R, 5R)-1-alkyl-4-Benzoyl-3,alkylamino,3,phenylalanine amides 5a-f.
Abstract: rel-(4R,5R)-4-Benzoylamino-5-phenyl-3-pyrazolidinone (1) was alkylated at position 1 with carbonyl compounds 2a-g. The corresponding rel-(4R,5R)-4-benzoylamino-5-phenyl-3-pyrazolidinone-1-azomethine imines 3a-g, were treated with sodium borohydride to give rel-(4R,5R)-1-alkyl-4-benzoylamino-5-phenyl-3-pyrazolidinones 4a-g. Reduction of pyrazolidinones 4a-g with Raney-nickel alloy in methanolic potassium hydroxide furnished rel-(4R,5R)-N-benzoyl-3-alkylamino-3-phenylalanine amides 5a-f.