New Heterocycles (new + heterocycle)

Distribution by Scientific Domains

Selected Abstracts

Studies on organophosphorus compounds: Synthesis and reactions of [1,2,4,3]triaza-phospholo[4,5- a]quinoxaline derivative

Hassan M. Moustafa
2,4-Bis-(4-methoxyphenyl)-1,3,2,4-dithiadiphosphetane-2,4-disulfide (Lawesson's reagent) (1) reacted with 2-hydrazino-3-methyl-quinoxaline (2) to give [1,2,4,3]-triazaphospholo[4,5- a]quinoxaline derivative 3. The Mannich reaction using different amines on compound 3 gave Mannich bases 4a,d. Also, compound 3 reacted with formaldehyde to give the corresponding 2-hydroxymethyl derivative 5, which upon reaction with thionyl chloride gave the corresponding chloromethyl derivative 6. Treatment of compound 6 with some thiols yielded the corresponding sulfides 7a,d. Acylation of compound 3 gave acylated compounds 8a,b. Compound 9, which was prepared through the reaction of compound 3 with ethyl cyanoacetate, was investigated as a starting material for the synthesis of some new heterocyclic systems 10,13. Also, reaction of compound 9 with carbon disulfide and 2 equivalents of methyl iodide in a one-pot reaction yielded the corresponding ketene-S,S-acetal 14, which in turn reacted with bidentates to give some new heterocycles 15,17. 2008 Wiley Periodicals, Inc. Heteroatom Chem 19:520,529, 2008; Published online in Wiley InterScience ( DOI 10.1002/hc.20473 [source]

Chemistry of phosphorus ylides 21 new route for the synthesis of azetidinones.

Reaction of phosphonium ylides with benzil-, o -naphthoquinone-, triketonemonoanils
Active vinylidenetriphenylphosphoranes are nucleophilic reagents which can be con- sidered as versatile synthons for the synthesis of new heterocycles. The active phosphacumulene ylides, namely N -phenylimino- 2a, 2-oxo- 2b or 2-thioxo-vinylidenetriphenylphosphoranes (2c), react with benzil- (1a,b), o -naphthoquinone- (8), or triketone-monoanils (11), to give the corresponding phenylimino- (3a, d, 9a, 12a), oxo- (3b, e, 9b, 12b), or thioxoazetidinones (3c, f, 9c, 12c), respectively, which constitute an important class of organic compounds with medicinal and biological importance. On the other hand, quinone monoanils 1a, 8, 11 can be converted by reaction with the stabilized alkylidenephosphoranes (5a,d), namely acetylmethylene- 5a, methoxycarbonylmethylene- 5b, ethoxycarbonylmethylene- 5c, and benzoylmethylene-triphenylphosphorane 5d, into the phosphoranylidenes (7a,d, 10a,d, 13a,d). No reaction was observed between iminophosphorane (14) and the monoanil (11). The structures of the new products were assigned according to consistent analytical and spectroscopic data. 2005 Wiley Periodicals, Inc. Heteroatom Chem 16:476,483, 2005; Published online in Wiley InterScience ( DOI 10.1002/hc.20144 [source]

Synthesis of new heterocycles containing more than one 1,2,3-thia or selenadiazole rings

Mousa Al-Smadi
The diketones 2a-d with different alkyl chain length are used for the synthesis of di-1,2,3-thia or selenadiazole derivatives 4a-d and 5a-d. The diketones 2a-d where prepared by a unique method through the reaction between the corresponding dibromoalkanes 1a-d and ethyl acetoacetate, which are transformed into the corresponding semicarbazone derivatives 3a-d. The di-1,2,3-thia or selenadiazole derivatives 4a-d and 5a-d were prepared from the semicarbazones derivatives 3a-d on oxidative cyclization with thionyl chloride and selenium dioxide respectively in high yield. [source]

ChemInform Abstract: Furan Ring Recyclization in 2-Furfurylthieno[2,3-b]pyridines: An Intramolecular N-Alkylation of Pyrrole Ring under Acid Conditions.

CHEMINFORM, Issue 34 2010
Darya Yu.
Abstract Depending on reaction conditions, the new heterocycles (V) and (VII) are formed from the 4-unsubstituted derivative (IVa). [source]