Synthesis of novel imidazo[1,2-a]pyrrolo[2,1-c][1,4]benzodiazepines and pyrimido[1,2-a]pyrrolo[2,1-c][1,4]benzodiazepines

Several 1 1-amino-5H-pyrrolo[2,1-c][1,4]benzodiazepines have been used as starting material to prepare a number of derivatives of 9H-imidazo[1,2-a]pyrrolo[2,1-c][1,4]benzodiazepines and 10H-pyrimido[1,2-a]pyrrolo[2,1-c][1,4]benzodiazepines. The imidazole nucleus was built by reaction of amidines with ethyl bromopyruvate or aminoacetaldehyde dimethylacetal. Several derivatives of imidazo[1,2-a]pyrrolo[2,1-c][1,4]benzodiazepine have been prepared by formylation of the pyrrole ring followed by formation of thioamides. Condensation of 11-amino-5H-pyrrolo[2,1-c][1,4]benzodiazepines with diethyl ethoxymethylenemalonate afforded intermediate diesters which were transformed into the corresponding 10H-pyrimido[1,2-a]pyrrolo[2,1-c]-benzodiazepines.     

Ring closure reactions with nitriles. I. Formation of pyrrolo [2,1-c] [1,2,4] benzothiadiazines and pyrrolo[1,2-a] quinazolines

Pyrrolo[2,1-c][1,2,4]benzothiadiazines have been prepared from the reactions of o-amino-benzenesulfonamides with γ-cyanopropionaldehydes. Pyrrolo[1,2-a]quinazolines have been prepared from the reaction of anthranilamides with either γ-cyanopropionaldehyde or succinic anhydride. The cyclization of a 4-oxo-2-quinazolinepropionic acid has produced a pyrrolo-[1,2-a]quinazoline and the isomeric pyrrolo[2,1-b]quinazoline.     

Synthesis of 5H-imidazo[2,1-c]pyrrolo[1,2-a][1,4]benzodiazepine

We have synthesized 5H-imidazo[2,1-c]pyrrolo[1,2-a][1,4]benzodiazepine 1 in five steps from 1-(2-amino-methylphenyl) pyrrole 4 . Amidino derivatives 11-12 have also been prepared.     

Synthesis of 5,8-dihydroxynaphtho[2,3-c][1,2,5]thiadiazole-6,9-dione and 6,9-dihydroxybenzo[g]quinoxaline-5,10-dione

The synthesis of 5,8-dihydroxynaphtho[2,3-c][1,2,5]thiadiazole-4,9-dione 3 , 6,9-dihydroxybenzo[g]quinoxaline-5,10-dione 4 , and their lesser oxygenated analogs via Friedel-Crafts and Diels-Alder synthesis is reported.     

Synthesis of pyrido[3,2-e]pyrrolo[2,1-c][1,2,4]triazines from pyrido[3,2-e][1,2,4]triazine derivatives

In carrying on our interest in heteropolycyclic structures with biological activities, we projected the preparation of compounds containing the pyrido[3,2-e][1,2,4]triazine or pyrido[2,3-b][1,4]triazepine systems. The established synthetic approach for the preparation of latter system led to the triazine derivatives 5a-f while a new bicyclic triazepine structure 6 is accomplished with difficulty. In expanding the pyridotriazine structure, we obtained derivatives of a new tricyclic structure, 5-substituted-6a-ethyloxycarbonyl-5,6,6a,7-tetrahydropyrido[2,3-e]pyrrolo[2,1-c][1,2,4]triazin-9(8H)-ones 8 in which the triazine ring is fused with a pyrrole nucleus. Compounds 5a-f and 8a,b will be tested as potential CNS depressant, antiinflammatory, analgesic and antibacterial agents.     

Efficient One-pot Synthesis of Pyrrolo[2,1-a]isoquinoline and Pyrrolo[1,2-a]quinoline Derivatives

A one-pot sequential reaction for efficient synthesis of pyrrolo[2,1-a]isoquinoline and pyrrolo[1,2-a]-quinoline derivatives has been developed. The reaction included firstly the Cu-catalyzed three-component reaction of isoquinoline(quinoline), acetylenedicarboxylate and alkynylbenzene and then Cs₂CO₃-promoted intramolecular cyclization reaction of initially formed 1-alkenyl-2-alkynyl-1,2-dihydroisoquinoline(1,2-dihydroquinoline).     

Novel routes to 1,2,3,4-tetrahydropyrrolo[1,2-a]pyrazines and 5,6,9,10,11,11a-hexahydro-8H-pyrido[1,2-a]pyrrolo[2,1-c]pyrazines

Condensation reactions of benzotriazole and 2-(pyrrol-1-yl)-1-ethylamine (1) with formaldehyde and glutaric dialdehyde, respectively, afforded intermediates 2 and 6. Subsequent nucleophilic substitutions of the benzotriazole group in 2 and 6 with Grignard reagents, sodium cyanide, and sodium borohydride gave 1,2,3,4-tetrahydropyrrolo[1,2-a]pyrazines 3a-e, 4, 5 and 5,6,9,10,11,11a-hexahydro-8H-pyrido[1,2-a]pyrrolo[2,1-c]pyrazines 7a-c, 8, 9, respectively, in good yields.     

Synthesis of a new bridgehead nitrogen heterocyclic system. Pyrrolo [2,1-f]-1,2,4-triazine derivatives

1-Ureidopyrroles of type 6a,b prepared by the general method previously described (2), readily cyclized under basic conditions giving pyrrolo [2,1-f]-1,2,4-triazine-2,4(1H, 3H)dione derivatives.     

Cleavage of Pyrrolo[2,1-c][1,4]benzoxazine-1,2,4-triones with Thiocarbonohydrazide. Synthesis of Substituted 4-Amino-1,2,4-triazines

Russian Journal of Organic Chemistry - 3-Acylpyrrolo[2,1-c][1,4]benzoxazine-1,2,4-triones reacted with thiocarbonohydrazide to give mixtures of...     

Synthesis and some properties of N-unsubstituted pyrrolo[2,1-c]-1,3-diazacycloalkano[1,2-a]pyrazinones

Reactions of methyl 2-(2-formyl-1H-pyrrol-1-yl)alkanoates with unsubstituted aliphatic 1,2-, 1,3-, and 1,4-diamines gave N-unsubstituted pyrrolo[2,1-c]-1,3-diazacycloalkano[1,2-a]-pyrazinones. Some of them show ring-chain tautomerism. Transformations of these compounds led to a number of novel heterocyclic systems: 2,10-dihydro-3H,5H-imidazo[1,2-a]-pyrrolo[1,2-d]pyrazines, 2,3,4,11-tetrahydro-6H-pyrrolo[1??,2??:4,5]pyrazino[1,2-a]pyrimidines, 1,2,3,5,6,10b-hexahydroimidazo[1,2-a]pyrrolo[2,1-c]pyrazines, 1,3,4,6,7,11b-hexahydro-2H-pyrrolo[2??,1??:3,4]pyrazino[1,2-a]pyrimidines, and 2,3,4,5,6,7-hexahydro-1H-pyrrolo[2,1-c]-[1,4,7]triazacycloundecin-8(9H)-one.     

Synthesis and selected properties of N-substituted pyrrolo[2,1-c]-1,3-diazacycloalkano[1,2-a]pyrazinones

The reactions of methyl α-(2-formyl-1H-pyrrol-1-yl)carboxylates with N-substituted aliphatic 1,2-, 1,3-, and 1,4-diamines afford new pyrrole-containing heterocyclic systems: 1,2,3,10b-tetrahydroimidazo[1,2-a]pyrrolo[2,1-c]pyrazin-5(6H)-ones, 1,3,4,11b-tetrahydro-2H-pyrrolo[2′,1′:3,4]pyrazino[1,2-a]pyrimidin-6(7H)-ones, and 1,2,3,4,5,12b-hexahydro-pyrrolo[2′,1′:3,4]pyrazino[1,2-a][1,3]diazepin-7(8H)-ones. The reduction of these compounds with different reagents was studied.     

Electronic spectra of pyrrolo[2,1-a]isoquinolines and pyrrolo[1,2-f]phenanthridines

The electronic absorption spectra of dioxo-compounds of the pyrroto[2,1-a]isoquinoline and pyrrolo[1,2-f]phenanthridine series and products of their condensation with o phenylenediamine were studied. The influence of substituents was demonstrated; halochromic phenomena in sulfuric acid medium were described; the fluorescence spectra are discussed.Institute of Technical Chemistry, Urals Branch of the Russian Academy of Sciences, Perm' 614600. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 650-653, May, 1995. Original article submitted March 14, 1995.     

Heterocyclic compounds with a bridgehead nitrogen atom. Synthesis in the imidazo[1,2-c]quinazoline series

The structures of imidazo[1,2-c]quinazolines were reexaminated and established by spectroscopic studies with the aid of high-field ¹H and ¹³ C nmr and mass spectra. In acidic media, 3 reacts to give the products of electrophilic substitution reaction and ring opening compound 5 , leading to the imidazo[1,2-c]benzo[e]-[1,2,3]triazine ring.