ABSTRACT
A conceptual strategy for a formal α-alkylation of α-methylene ketones was developed. Diverse 1° and 2° alkyl substituents were generated in the α-position of various ketones via synthesis of enaminone (step 1) and treatment with organomagnesium (step 2) with subsequent catalytic hydrogenation (step 3, 1° alkyl) or organocopper reagents (step 4, 2° alkyl). Tolerance toward ester, Boc-protected amine, and α-fluoro-substituted ketone moieties was demonstrated. The suitability of the method for late-stage natural product modification was shown.
ABSTRACT
A one-step synthesis of functionalized 3-azabicyclo[3.2.0]heptanes by [2+2]-photochemical intermolecular cycloaddition of N-benzylmaleimide to alkenes was elaborated. The obtained compounds were easily transformed into the bi- and tricyclic analogues of piperidine, morpholine, piperazine, and GABA, which are advanced building blocks for drug discovery.
ABSTRACT
Intramolecular photochemical [2 + 2]-cyclization of acetophenone enamides gave 2-azabicyclo[3.2.0]heptanes, advanced building blocks for drug discovery. Synthesis of a conformationally restricted analogue of proline, 2,3-ethanoproline, was performed.
ABSTRACT
In the context of drug discovery, novel spirocyclic pyrrolidines have been synthesized in two steps from common three- to seven-membered-ring (hetero)alicyclic ketones. The key transformation is a reaction between an electron-deficient exocyclic alkene and an in situ generated N-benzyl azomethine ylide. The developed method has been used to synthesize the central diamine core of the known antibacterial agents Sitafloxacin and Olamufloxacin.
Subject(s)
Anti-Bacterial Agents/chemical synthesis , Pyrrolidines/chemistry , Spiro Compounds/chemistry , Anti-Bacterial Agents/chemistry , Catalysis , Cycloaddition Reaction , Drug Design , Palladium/chemistry , Pyrrolidines/chemical synthesisABSTRACT
We have developed a rapid two-step synthesis of substituted 3-azabicyclo[3.2.0]heptanes which are attractive building blocks for drug discovery. This new method utilizes very common chemicals, benzaldehyde, allylamine, and cinnamic acid, via intramolectular [2+2]-photochemical cyclization.
Subject(s)
Benzaldehydes/chemical synthesis , Cinnamates/chemical synthesis , Drug Discovery , Benzaldehydes/chemistry , Cinnamates/chemistry , Cyclization , Molecular Structure , Photochemical Processes , SolubilityABSTRACT
A series of novel sulfonamide substituted heteroleptic salan titanium(IV)-bis-chelates complexed to 2,6-pyridinedicarboxylic acid were synthesized, structurally characterized and evaluated for their anticancer activity against two human carcinoma cell lines. All cytotoxic complexes showed complete inhibition of cell growth at active concentration, two complexes based on pyrrolidine and azepane substituted sulfonamides displayed IC50 values below 1.7 µM and are more cytotoxic than cisplatin in both tested cell lines. The azepane substituted complex [L3Ti(dipic)] exhibited excellent activity with an IC50 value of 0.5 ± 0.1 µM in Hela S3 and 1.0 ± 0.1 µM in Hep G2.
Subject(s)
Antineoplastic Agents/chemical synthesis , Chelating Agents/chemistry , Coordination Complexes/chemical synthesis , Sulfonamides/chemistry , Titanium/chemistry , Antineoplastic Agents/chemistry , Antineoplastic Agents/toxicity , Cell Survival/drug effects , Coordination Complexes/chemistry , Crystallography, X-Ray , HeLa Cells , Hep G2 Cells , Humans , Magnetic Resonance Spectroscopy , Molecular Conformation , Picolinic Acids , Pyridines/chemistryABSTRACT
A set of novel SO2-containing azabicyclo[3.n.1]alkanes has been synthesized by the double-Mannich annulation of of the corresponding monocyclic S-ketones. These compounds have been rationally designed as 3D-shaped, conformationally restricted SO2-containing building blocks for drug discovery.
