The synthesis and stereochemistry of some pyrido[3,4-d]carbazole derivatives

Pyrido[3,4-d]carbazole derivatives have been synthesised from N-acetyl-5-oxodecahydro-isoquinoline by the Fischer indole synthesis, and their stereochemistry established by ¹H-NMR spectroscopy. In contrast to experience with simpler systems, cyclisation in acetic acid gave only the alternative pyrido[3,4-a]-carbazole, and the desired pyrido[3,4-d]carbazole formation occurred only in the presence of sodium acetate.     

Facile synthesis of novel indolo[3,2-b]carbazole derivatives and a chromogenic-sensing 5,12-dihydroindolo[3,2-b]carbazole

Novel indolo[3,2-b]carbazole derivatives and a chromogenic-sensing 5,12-dihydroindolo[3,2-b]carbazole have been synthesized starting from tetra-tert-butylated 6,12-diaryl-5,11-dihydroindolo[3,2-b]carbazoles, which were prepared via an efficient tert-butylation of 6,12-diaryl-5,11-dihydroindolo[3,2-b]carbazoles.     

Carbazolo[2,1‐a]carbazole derivatives via fischer indole synthesis

A series of new carbazolo[2,1‐a]carbazoles was synthesized from 4‐oxo‐1,2,3,4‐tetrahydrobenzo[a]‐carbazole derivatives.     

A photochemical synthesis of 11H-benzo[a]carbazole

11H-Benzo[a]carbazole was prepared from 5-acetamido-1,2,3,4-tetrahydronaphthalene in four steps. A Goldberg arylation followed by hydrolysis afforded N-phenyl-1,2,3,4-tetrahydro-5-naphthylarnine ( 3 ). Photolysis of 3 produced 1,2,3,4-tetrahydro-11H-benzo[a]carbazole ( 4 ) which was converted to 11H-benzo[a]-carbazole by dehydrogenation with chloranil.     

Synthesis and aminomethylation of derivatives of pyrazino[3.2.1-jk]carbazole and diazepino[3.2.1-jk]carbazole

Derivatives of pyrazino- and diazepino[3.2.1-jk]carbazoles were obtained by the Fischer condensation of 1-amino-3-oxo-1,2,3,4-tetrahydroquinoxaline and 1-amino-4-oxo-2,3-dihydrobenzodiazepine(1,5) with cyclohexanone and 3-methylcyclohexanone. A study was carried out on the transformations of derivatives of pyrazino- and diazepino[3.2.1-jk]carbazoles by methylation at the NH group and aminomethylation of the N-methyl derivatives.     

The synthesis of some derivatives of benzo[f]naphtho[1,8-bc]thiepin-12-one

The preparations of benzo[f]naphtho[1,8-bc]thiepin-12-one, its 6-methyl and 6-methoxy derivatives and their corresponding sulfoxides and sulfones are described. They involve the coupling of suitable halogen naphthyl derivatives with thiophenoxides with the help of copper and the cyclization of the resulting acids with phosphorus pentoxide in benzene. The oxidations to sulfoxides and sulfones were performed with iodo-benzene diacetate and hydrogen peroxide, respectively. The ir and pmr spectra are reported.     

Synthesis of new pyrido[3,4-c]carbazole derivatives

Previously unknown 2-[6-hydroxy-9-(4-methoxyphenyl)-1,2,3,9-tetrahydro-4H-carbazol-4-ylidene]malononitrile was synthesized by the Nenitzescu reaction and was used for the construction of new tetracyclic compounds, viz., pyrido[3,4-c]carbazoles. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1600–1604, September, 2006.     

The synthesis of heterocyclic derivatives of dibenzo[a,d]cycloheptene

The synthesis of 2-amino-7,8-dihydrobenzo[1,2]cyclohepta[3,4,5-de]quinazoline ( 10 ) and 6,7-dihydrobenzo[1,2]cyclohepta[3,4,5-cd]indazole ( 5 ) is described.     

The synthesis of pyrazino[2,3-d]pyridazine and some of its derivatives

Pyrazino[2,3-d]pyridazine (I) was synthesized by two different routes. 5, 8-Dihydroxy-pyrazino[2, 3-d]pyridazine (IV) was converted to 5, 8-dichloropyrazino[2, 3-d]pyridazine (V) and 5, 8-dibromopyrazino[2, 3-d]pyridazine (Va). When V was treated with various benzyl mercaptans and alkoxides the corresponding disubstituted derivatives were obtained. Compound V when allowed to react with aromatic amines gave 5, 8-bisamino-pyrazino[2,3-d]pyridazines, however, with aliphatic amines only mono substituted products were obtained substituted in the 8-position. The reaction of pyrazine-2, 3-dinitrile with hydrazine gave 5, 8-diaminopyrazino[2, 3-d]pyridazine (X).     

One-step synthesis of some polyfluoroalkylated 1,3-benzodioxoles, 4H-l,3-benzodioxins anddibenzo[d,f] [l,3]dioxepins

Several polyfluoroalkylated heterocyclic compounds containing methylenedioxy group such as 2-(F-alkyl) substituted 1,3-benzodioxole, piperonal, 4H-1,3-benzodioxin, 1,3-dioxolane and 6-(F-alkyl) substituted dibenzo[d,f][1,3]dioxepin have been prepared through double Michael-addition reactions of 2,2-dihydropolyfluoroalkanoates with the corresponding diphenols or diols in high yields.     

One-pot multicomponent synthesis of some 5,6-dihydro-benzo[h]quinoline derivatives

5,6-Dihydrobenzo[h]quinoline derivatives 4a–f and 5a–c were prepared via condensation of the corresponding arylidenes 2, with 1-tetralone in the presence of ammonium acetate and sodium methoxide, respectively, following thermal, microwave and ultrasound methodologies. The yields of 4a–f were moderate when the latter two methodologies used, but the products were pure. Ultrasound and microwave irradiation methods were also used in the synthesis of 4-aryl-3-cyano-1,2,5,6-tetrahydro-benzo[h]quinoline-2-ones (6a–e) and its analogues 7a,b. The majority of compounds 4–7 were synthesized via one-pot multicomponent reactions of aldehydes, active cyanomethylene compounds, 1-tetralone and ammonium acetate. Attempts to cyclocondensation of the aminocyano derivative 4a,d with acetic anhydride in presence of conc. H₂SO₄ failed; instead the acetylamino derivative 8 was isolated. On the other hand, refluxing of 4d with formamide in DMF led to the formation of dihydrobenzo-pyrimidoquinoline 9 giving good yield. All prepared condensates were structurally elucidated by various spectroscopic methods. Screening of the potential cytotoxicity for compounds 4a–f on five cell lines, namely: colorectal carcinoma (HCT-116), Hepatocellular carcinoma (HEPG2), Human breast adenocarcinoma (MCF7), Cervix adenocarcinoma (HELA) and Glioblastoma (U251), did not show any cytotoxic activity.     

Efficient synthesis of 8-oxa-bicyclo[3.2.1]octane derivatives from d-arabinose

Our studies of the TIBAL-promoted Claisen rearrangement reaction and ring-closing metathesis (RCM) resulted in the development of an efficient synthetic route to polyfunctional seven-membered carbasugar synthons from d-arabinose. Moreover, the construction of 8-oxa-bicyclo[3.2.1]octane derivatives 10 and 13 was achieved by BCl₃ or iodide-promoted intramolecular electrophilic addition reactions, which were regio- and stereoselective.     

The synthesis of some benzo[d,d']diisothiazoles

Four examples of benzo[d,d']diisothiazoles have been made by cyclisation of appropriate o-alkylthioaryl-ketoximes by simultaneous or consecutive ring formation.     

The synthesis of some pyrido[1,4] benzoxazepines and a dipyrido[1,4] oxazepine

Synthetic routes to pyrido[2,3-b]-, pyrido[4,3-b]-, pyrido[3,2-f] [1,4]benzoxazepines and dipyrido[2,3-b:2,3-f] [1,4]oxazepine are described. The applicability of one of the methods to dibenz[b,f] [1,4]oxazepine synthesis is discussed.     

Design,synthesis and antifungal activity of carbazole derivatives

The incidence of invasive fungal infections is increasing rapidly. Clinically available antifungal agents suffer from limited efficacy and severe resistance. There is an urgent need to discover antifungal lead compounds with novel chemical scaffold. On the basis of our previously identified tetrahydrocarbazole antifungal leads, the structure-activity relationship was further explored by modifying the scaffold and the side chains. Several targeted compounds showed potent activity against Candida species. Particularly, compound 13i showed better antifungal activity than the lead compound, which can be used as a good starting point for further optimization.     

Thermolysis of 3-azidophenalen-1-ones to naphtho[8,1-ab]carbazolones and naphtho[8,1-ab]-8a-azonia-9-λ2-azafluoren-7-ones

3-Azido-1-phenalenones 4 with aryl- or hetarylsubstituents in position 2 cyclized by thermolysis to give naphtho[8,1-ab]carbazolones 5 or naphtho[8,1-ab]-8a-azonia-9-λ²-azafluorenones 7. Reduction of the azides 4 gave the corresponding amino derivatives 9. The thermolysis conditions were studied by differential scanning calorimetry.     

A novel synthesis of 6,7,8,9-tetrahydro-5H-dibenzo[c,g]carbazole

The synthesis of the title compound from 2-tetralone and thiosemicarbazide is reported. The structure was obtained by X-ray crystallography and its evaluation in certain anticonvulsant, cytotoxic and DNA binding screens is described.