Four new heteroaromatic pentalenes have been synthetised by reductive cyclisation with triethylphosphite of the appropriate nitropyridylbenzotriazoles or nitrophenyltriazolo [4,5‐b] pyridines: the [2,3‐b] pyridino [4,5] benzo‐1,3a,6,6a‐tetraazapentalene 2; [3,2‐c] pyridino [4,5] benzo‐1,3a,6,6a‐tetraazapentalene 3; [3,2‐b] and [2,3‐b] pyridino [5,6] benzo‐1,3a,4, 6a‐tetraazapentalene 5,6. The spectral properties of these new compounds are described.
Bull. Soc. Chim. B e l q . vo1.92/nn 1/1983 SYNTHESE ET REACTIVITE DU [9,2-b] PYRIDINO [ 4 , 5 1 BENZO-l,3a,6,6a-TETRAAZAPENTALENE. A. MAQUESTIAU, M. FLAMMANG-BARBIEUX et E. VILAIN. Laboaatoihe de Chimie Ohganique, hiVehbi.t6? d e 1'Eta.t ir Monb. ABSTRACT. A new heteroaromatic pentalene, [3.2-b] pyridino [ 4 , 5 ] benzoil,3a,6,6a-t&traazapentalene [3] has been prepared by direct condensation of 2-chloro-3-ni-tropyridine with benzotriazole followed by reductive cyclisation of the l-(3'n i t r o -2 ' -p y r i d y l ) b e n z o t r i a z o l e intermediate with triethylphosphite. The spectral and chemical properties of this new compound are described and the positions of the introduced substituents are determined a s well by 'H NMR spectroscopy as by EHT calculations.
Bull. SOC. Chim. Belg. vo1.93/n011/1984 SYNTHESE ET REACTIONS DE DEPLACEMENT NUCLEOPHILE DE DERIVES NITRES ET HALOGENES DU [ 3,2-b] PYRIDINO [ 4,5 I BENZO-1,3a, 6,6a-TETRAAZAPENTALENE.* A. MAQUESTIAU, M. FLAMMANG-BARBIEUX et E. VILAIN. U n i u e a b i t t de C'Etat, Labofiatoiae de C h i n i e Oaganique, 1 0 0 0 Monb I l e t g i q u e ) . hcrivrd : 12/10/1984 -Accrptad : 05/11/1984 ABSTRACT. T h e reactions of [3,2-b] pyridino [4,5] benzo-l,3a.6,6a-tetraarapentalene [I] and i t s nitroor halogeno-derivatives w i t h some electrophiles and nucleophiler a r e described. T h e directive influence of the tetraazapentalene nucleus o n electrophilic and nucleophilic substitution reactions at the pyridine and the benzene rings is discussed. INTRODUCTION. Les betaines rnesomeriques iso-n-electroniques du dianion pentalenique constituent une famille importante de composes heteroaromatiques") . Parmi ces derives, les tetraazapentalenes possedant deux atomes d'azote conununs aux cycles ne peuvent Btre representes sans separation de charges et prdsentent des proprietes chimiques qui sont liees a la nature n-deficiente ou n-excedentaire des atomes d'azote. Nous avons decrit precedemment la synthese du [3,2-bl pyridino [4,51 benzo-1, 3a,6,6a-tetraazapental&ne 111 (2). Les diverses formes canoniques possibles de [I] constituent une indication de la versatilite de la polarisabilite de la molecule, le systeme tetraazapentalenique pouvant agir a la fois c o m e accepteur et donneur d'electrons. Les substitutions tant electrophiles que nucleophiles en ortho et para par rapport aux atomes d'azote non communs aux cycles doivent donc Btre activees. Ces activations au niveau des cycles benzenique et pyridinique ne pourront evidemment pas etre equivalentes. Ces problemes constituent l'objet du present travail. *Dedie au Professeur R.H. MARTIN a l'occasion de son 70eme anniversaire.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.