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Heterocyclic Ring Systems (heterocyclic + ring_system)

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Chemistry100%

Selected Abstracts

Solution Phase Synthesis of Imidazo[1,2-b]pyrazol-2-one, an Interesting 5,5-Fused Heterocyclic Ring System.

CHEMINFORM, Issue 17 2004
Benjamin E. Blass
Abstract For Abstract see ChemInform Abstract in Full Text. [source]

Novel Fused Pyrrole Heterocyclic Ring Systems as Structure Analogs of LE 300: Synthesis and Pharmacological Evaluation as Serotonin 5-HT2A, Dopamine and Histamine H1 Receptor Ligands

ARCHIV DER PHARMAZIE, Issue 2 2010
Sherif A. F. Rostom
Abstract LE 300 represents a structurally novel type of antagonists acting preferentially at the dopamine D1/D5 receptors and the serotonin 5-HT2A receptor. This compound consists of a ten-membered central azecine ring fused to an indole ring on one side and a benzene moiety on the other side. To estimate the importance of the indole and / or phenyl moieties in this highly active benz-indolo-azecine, both rings were removed and replaced with a 1H -pyrrole counterpart. Accordingly, some new analogs of LE 300 namely, pyrrolo[2,3- g]indolizine, pyrrolo[3,2- a]quinolizine rings and their corresponding dimethylpyrrolo[2,3- d]azonine, and dimethylpyrrolo[2,3- d]azecine were synthesized to be evaluated for their activity at the 5-HT2A and dopamine D1, D2L, D4, D5 receptors in relation to LE 300. In addition, their activity at the H1 -histamine receptors was also determined. The results suggested that the rigid pyrrolo[2,3- g]indolizine 7 and pyrrolo[3,2- a]quinolizine 8 analogs lacked biological activity in the adopted three bioassays. However, their corresponding flexible pyrrolo[2,3- d]azonine 11 and pyrrolo[2,3- d]azecine 12 derivatives revealed weak partial agonistic activity and weak antagonistic potency at the serotonin 5-HT2A and histamine H1 receptors, respectively. Meanwhile, they showed no affinity to any of the four utilized dopamine receptors. Variation in ring size did not contribute to a significant influence on the three tested bioactivities. Removal of the hydrophobic moiety (phenyl ring) and replacement of the indole moiety with a 1H -pyrrole counterpart led to a dramatic alteration in the profile of activity of such azecine-type compounds. [source]

ChemInform Abstract: The Synthesis of Novel Polycyclic Heterocyclic Ring Systems via Photocyclization.

CHEMINFORM, Issue 25 2001
Part 23.
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source]

Intramolecular Photochemical Cross-Coupling Reactions of 3-Acyl-2-haloindoles and 2-Chloropyrrole-3-carbaldehydes with Substituted Benzenes

ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 17 2009
Shen-Ci Lu
Abstract Highly efficient syntheses of indolo[2,1- a]isoquinolines, indolo[2,1- a][2]benzazepines, pyrrolo[2,1- a]isoquinolines and pyrrolo[1,2- a]benzazepines in excellent yields have been achieved by the intramolecular photochemical cross-coupling reactions of 3-acyl-2-halo- N -(,-arylalkyl)indoles and 2-chloro- N -(,-arylalkyl)pyrrole-3-carbaldehydes in acetone. A new heterocyclic ring system , pyrrolo[1,2- d][1,4]benzoxazepine , has also been constructed for the first time in this work by the photocyclization of 2-chloro- N -(2-phenoxyethyl)pyrrole-3-carbaldehyde. [source]

Synthesis of oxazolo[3,2- b]hetero[1,2,4]thiadiazine S,S-dioxides ,

JOURNAL OF HETEROCYCLIC CHEMISTRY, Issue 5 2005
Salvador Vega
Six bromomethyl derivatives of the new 2,3-dihydrooxazolo[3,2- b]thieno[3,4- e][1,2,4]thiadiazine 5,5-dioxides, 2,3-dihydrooxazolo[3,2- b]thieno[2,3- e][1,2,4]thiadiazine 5,5-dioxides and 6,7-dihydrooxazolo-[3,2- b]pyrazolo[4,3- e][1,2,4]thiadiazine 9,9-dioxides heterocyclic ring systems were synthesized. These compounds are good intermediates for the preparation and development of promising antiviral and psy-chotropic drugs. The structures of the products are supported by different nmr spectroscopic methods and mass spectrometry. [source]

The synthesis of novel polycyclic heterocyclic ring systems via photocyclization.

JOURNAL OF HETEROCYCLIC CHEMISTRY, Issue 4 2000
3- a]quinoline, 3- c][, 3- c]quinoline, 3- c]quinoline§, 4]triazolo[, 5]thieno[, Dibenzo[f, dibenzo[f, h]benzothieno[, h]naphtho[
Photocyclization of 3-chloro- N -(9-phenanthryl)benzo[b]-thiophene-2-carboxamide (3) and 3-chloro- N -(9-phenanthryl)-naphtho[1,2- b]thiophene-2-carboxamide (10) yielded dibenzo[f,h]benzothieno[2,3- c]-quinolin-10(9H)-one (4) and dibenzo[f,h]naphtho[2,,1,:4,5]thieno[2,3- c]quinolin-10(9H)-one (11), respectively. Further elaboration of the lactams provided three novel unsubstituted new ring systems. [source]

The synthesis of novel polycyclic heterocyclic ring systems via photocyclization.

JOURNAL OF HETEROCYCLIC CHEMISTRY, Issue 1 2000

Photocyclization of 3-chloro- N -(3-phenanthryl)naphtho[1,2- b]thiophene-2-carboxamide (12) furnished only one of the two possible isomers, i.e., naphtho[2,,1,:4,5]thieno[2,3- c]naphtho[1,2- f]quinolin-6(5H)-one (13), which was further elaborated to yield the unsubstituted ring system 7, its triazole 8 and tetrazole 9. The structural confirmation of 7 was accomplished by the total assignment of its 1H and 13C nmr spectra utilizing the concerted two-dimensional nmr spectroscopic experiments. [source]

Synthesis and Structure-Activity Relationship Studies of Pyrazole-based Heterocycles as Antitumor Agents

ARCHIV DER PHARMAZIE, Issue 7 2010
Ahmad M. Farag
Abstract Several 4-cyano-1,5-diphenylpyrazoles attached to different heterocyclic ring systems at position 3 were synthesized starting from ethyl 4-cyano-1,5-diphenyl-1H -pyrazole-3-carboxylate 1. The newly synthesized compounds were tested in vivo for their anti-estrogenic effects and evaluated in vitro for their cytotoxic properties against estrogen-dependent tumors. 3-(5-Mercapto-1,3,4-oxadiazole-2-yl)-1,5-diphenyl-1H -pyrazole-4-carbonitrile 13 revealed the highest cytotoxic activity with a GI50 value equal to 40 nM against the IGROVI ovarian tumor cell line. It also showed an anti-estrogen activity 1.6 more effective than the reference drug, in addition to a high tolerable dose. 3-(5-(Methylthio)-4-phenyl-4H -1,2,4-triazol-3-yl)-1,5-diphenyl-1H -pyrazole-4-carbonitrile 7 was found to have the highest anti-estrogenic activity, while 1,5-diphenyl-3-[5-(phenylamino)-1,3,4-thiadiazol-2-yl]-1H -pyrazole-4-carbonitrile 11 showed the lowest activity. The oral LD50 values revealed that most of the tested compounds are relatively nontoxic. [source]