Syntheses of Examples of the 5,6-dihydro-4H-[1,2,3]triazolo[4,5,1-ij]quinoline, 4,5,6,7-tetrahydro[1,2,3]triazolo[4,5,1-jk][1,4]benzodiazepine,and 5,6,7,8-tetrahydro-4H-[1,2,3]triazolo[4,5,1-kl][1]benzazocine ring systems

Lithiation of 1-vinylbenzotriazole 9 with n-BuLi (2 equiv) generates dianion 10, which upon subsequent reaction with 1,2- and 1,4-diketones affords 14 and 13, representatives of the 5,6-dihydro-4H-[1,2,3]triazolo[4,5,1-ij]quinoline 1 and 5,6,7,8-tetrahydro-4H-[1,2,3]triazolo[4,5,1-kl][1]benzazocine 2 ring systems, respectively. Reactions of dianion 10 with isocyanates give 15a,b, which contain the 4,5,6,7-tetrahydro[1,2,3]triazolo[4,5,1-jk][1,4]benzodiazepine 3 ring system.     

5,6-Dihydro-4H-imidazo[4,5,1-i,j]quinoline derivatives

The oxidation of 2-hydroxymethyl and 2-methyl derivatives of 5,6-dihydro-4H-imidazo[4,5,1-i,j] quinoline with active manganese dioxide and selenium dioxide gave 2-formyl derivatives of this heterocycle. Some transformations of these compounds are realized.See [1] for communication I.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 967–969, July, 1971.     

5,6-Dihydro-4H-imidazo[4,5,1-i,j]quinoline derivatives

9-Substituted 5,6-dihydro-4H-imidazo[4,5,1-i,j]quinolines were synthesized and aminated by the action of sodium amide and hydroxylated by fusing with potassium hydroxide. The mononitro and dinitro compounds of some 5,6-dihydro-4H-imidazo[4,5,1-i,j]quinoline deivatives and the corresponding amino and diamino compounds were obtained. The latter react with nitric or formic acids to form a new heterocyclic ring.See [1] for communication II.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 242–246, February, 1972.     

Synthesis and reactions of some dihydro and tetrahydro-4H-imidazo[5,4,1-ij]quinoline derivatives

Reaction of phenyl N-(8-quinolinyl)carbamate with sodium borohydride afforded 1,2-dihydro-4H-imidazo-[5,4,1-ij]quinolin-2-one, 2a . The 5,6-double bond of 2a was functionalized by reaction with nitrosyl chloride to give the nitroolefin 4 and by reaction with hypobromous acid to give the trans-bromohydrin 5 . Reaction of 5 with sodium azide led to the rearranged trans-6-azido-5-ol 7 , the structure of which was determined by ¹H nmr studies.     

An Efficient One-pot Synthesis of 4H-Pyrrolo[3,2,1-ij]quinolines

Summary. Dialkyl 4H-pyrrolo[3,2,1-ij]quinoline-4,5-dicarboxylates are obtained in quantitative yields from the 1:1:1 addition reaction between triphenylphosphine, dialkyl acetylenedicarboxylates, and indole-7-carboxaldehyde.     

Synthesis and Properties of 1,3-Diaryl-5,6-dihydro-8H-imidazo[2,1-c]-1,4-oxazinium Bromides

It has been established that the condensation of 3-(4-methoxyphenylamino)-5,6-dihydro-2H-1,4-oxazine with substituted phenacyl bromides occurs at the exocyclic nitrogen atom with formation of 3-aryl-3-hydroxy-1-(4-methoxyphenyl)-2,5,6,8-tetrahydro-3H-imidazo[2,1-c]-1,4-oxazinium bromides. By treatment of the latter with acetic anhydride 3-aryl-1-(4-methoxyphenyl)-5,6-dihydro-8H-imidazo[2,1-c]-1,4-oxazinium bromides are formed. The structures of the compounds synthesized were determined via ¹H NMR spectroscopy and X-ray diffraction.     

Some 5,6-dihydro-4H-pyrrolo[3,2,1-i,j]quinolines

On the basis of structural features which relate 5,6-dihydro-4H-pyrrolo[3,2,1-i,j]quinolines to indoles, several representative groups of derivatives were synthesized.     

A Novel synthesis of 5,6-dihydro-2,3-bisaryl-8H-imidazo[2,1-c][1,4]thiazine

Bisaryl-8H-imidazo[2,1-c][1,4]thiazines were prepared from the corresponding 2-thiomethylimidazoles. A novel and efficient synthesis is presented for these intermediates based on the condensation of benzils with protected 2-thioacetaldehydes.     

5,6-Dihydro-4h-imidazole[4,5,1-i,j]quinoline derivatives

2-Alkyl(dialkyl)amino derivatives of I and their respective cyclic ammonium salts were obtained by reaction of the 2-chloro derivative of 5,6-dihydro-4H-imidazole [4,5,1-i,j ]quinoline (I) and its methiodide with amines. The eycloammonium salt was converted into 2-amino(alkylimino)-l,2-dihydro derivatives of 5. Methoxy- and methyl-substituted I readily formed 2-amino derivatives by reaction with sodium amide. Comparison of the UV spectra of the 2-amino derivative of I and its fixed tautomeric form indicates that the 2-amino derivative of I exists primarily in the amino form in dioxane and CC14.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1410–1413, October, 1970.     

Synthesis and structural assignment of 5,6-dihydro-8-hydroxy-9-methoxy-1H,7H-benzo[ij] quinolizine-1,7-dione

The compound 5,6-dihydro-8-hydroxy-9-methoxy-1H,7H-benzo[ij]quinolizine-1,7-dione ( 4a ) was synthesized from 3-(1,4-dihydro-6,7-dimethoxy-4-oxo-1-quinolyl)propionic acid ( 3a , free base), involving spontaneous demethylation with ring closure. The structural assignment of 4a was based on an analogous, unequivocal synthesis of 5,6-dihydro-9-ethoxy-8-hydroxy-1H,7H-benzo[ij]quinolizine-1,7-dione hydrochloride ( 4b ).     

Synthesis of 2,3-dihydro-1H-imidazo[1,2-b]pyrazoles

Two novel 2,3-dihydro-1H-imidazo[1,2-b]pyrazole derivatives 7 and 8 have been prepared by hydrazinolysis with 2,4-dinitrophenylhydrazine of 1-(benzylideneamino)-2-(2-ethoxycarbonyl-2-nitromethylidene)-imidazolidine 4 . The precursor 4 was conveniently prepared from ethyl nitroacetate and 1-(benzylidene-amino)-2-(methylthio)imidazoline 3 . Two examples are presented in which ethyl aceto(and trifluoroaceto)acetate 2-nitrophenyl-hyrazone, 9 and 10 , both of which also feature the β-hydrazinoacrylate arrangement, are refluxed in ethanol containing hydrochloric acid and thereby converted into pyrazolones 11 and 12 , pyrazoles 13 and 14 , and ketone 2-nitrophenylhydrazones 15 and 16 , respectively.     

Synthesis of 5,6-dihydro-4H-pyrrolo[1, 2-a] [1,4]benzodiazepines

The title compounds are. Prepared by the reaction of carbonyl compounds with 1-(2′-amino-methylphenyl)pyrrole hydrochloride.     

Novel heterocycles. 13 Synthesis of 5,6-dihydro-1H-3H-pyrrolo[3,2,1-ij][3,1]benzoxazine-1,3-dione

The synthesis of 5,6-dihydro-1H,3H-pyrrolo[3,2,1-ij][3,1]benzoxazine-1,3-dione ( 2a ), a new ring system, from N-acetylindoline is described.     

Synthesis of 5,6-dihydro-4H-pyrrolo[1,2-a]thieno[2,3-f][1,4]diazepines

The reduction of 1-[3-(thienyl-2-carbonitrile)]pyrrole, formed by condensation of 3-aminothiophene-2-carbonitrile with 2,5-dimethoxytetrahydrofuran, gave 1-[3-(thienyl-2-aminomethyl)]pyrrole. This compound was found to be a convenient intermediate for the preparation of 4-aryl-5,6-dihydro-4H-pyrrolo[1,2-a]thieno-[2,3-f][1,4]diazepines which was accomplished by two different synthetic routes.     

Synthesis of 4-aryl-2,6,6-trimethyl-5-oxo-5,6-dihydro-4H-thieno[3,2-b]pyrroles

The method for the synthesis of 4-aryl-2,6,6-trimethyl-5-oxo-5,6-dihydro-4H-thieno[3,2-b]pyrroles from accessible 4-aminothiophene derivatives was developed.     

Synthesis of substituted 4H-imidazo[5,1-b]benzimidazoles

4-Methyl-1-phenylimidazo[5,1-b]benzimidazole (III) has been synthesized. It has been shown that 1,4-dimethylimidazo[5,1-b]benzimidazole (I) and III readily undergo acetylation and nitrosation at position 3. The reaction of I and III with formalin, like the Mannich reaction, leads to the formation of methylenebis derivatives. The bromination of III with N-bromosuccinimide forms the 3-bromo derivative of III (X).For part IV, see [1].     

Synthesis of some pyrimido[4′,5′:4,5]thieno[2,3-b]quinolines and related heterocycles

Several thieno[2,3-b]quinolines 6a-i have been synthesized. These compounds were used as key intermediates in the synthesis of oxazino[4′,5′:4,5]thieno[2,3-b]quinoline 8 , pyrimido[4′,5′:4,5]-thieno[2,3-b]quinolines 9–12 , triazino[4′,5′:4,5]thieno[2,3-b] quinolines 14 and imidazo[4′,5′:4,5]-thieno[2,3-b]quinolines 17 .     

Novel synthetic approach to 6,7-dihydro-5H-imidazo[1,5-a]-pyrazin-8-ones

[reaction: see text] A novel route to highly substituted chiral 6,7-dihydro-5H-imidazo[1,5-a]pyrazine-8-ones starting from Meldrum's acid is disclosed. The key features of the methodology are the incorporation of amino esters as a chiral pool and facile mild intramolecular cyclization to form the pyrazine ring. Incorporation of various substituents at different stages of the synthesis from various building block sets makes this methodology readily amenable to parallel synthesis.