Amination of pyrido[3,2,1‐jk]carbazol‐6‐ones

Amination of 4‐hydroxypyridocarbazolones 1 with aniline or benzylamine gave in good yields 4‐amines 3 . With piperidine in a sealed tube from 4‐hydroxy‐ or 4‐chloro‐5‐alkylpyridocarbazolones 1 or 4 ring opened 1‐acylcarbazoles 5 were obtained. Only 4‐hydroxy‐5‐phenyl‐pyridocarbazolone 1d gave 4‐amines 6 . Reduction of 4‐azidopyridocarbazolones 7 either by catalytic hydrogenation or in a 2‐step synthesis via phosphazenes 8 gave 4‐aminopyridocarbazolones 9 . Amines 9 were also obtained from benzylamines 3 by catalytic debenzylation. A one step amination of 4‐hydroxy‐5‐phenylpyridocarbazolone 1d via debenzylation to 9d was observed by reaction with benzylammonium chloride. At elevated temperatures the highly fused 6,13b‐diazaindeno[1,2,3‐hi]chrysenone 10 was formed from 1d .     

Synthesis and reactions of pyrido[3,2,1‐jk]carbazole‐4,6‐diones

Pyrido[3,2,1‐jk]carbazoles 1 , synthesized from carbazoles and alkyl‐ or arylmalonates, gave regioselective electrophilic substitution reactions at position 5 such as chlorination to 5‐chloro derivatives 2 , nitration to 5‐nitro compounds 3 , or hydroxylation to 5‐hydroxy derivatives 4 . 5‐Hydroxy compounds 4 gave on treatment with strong bases ring contraction to 5 , 6 or the ring opening product 7 . Exchange of the chloro group in 2 with azide or amines gave the corresponding azides 8 and the 5‐amino derivatives 9 and 10 . Alkylation of 1 with benzyl chloride or allyl bromide resulted in the formation of 5‐C‐alkylated products 11 together with 4‐alkyloxy derivatives 12 . J. Heterocyclic Chem., 48, 1039 (2011).     

5‐Unsubstituted Pyrido[3,2,1‐jk]carbazol‐6‐ones: Syntheses,Substitution, and Cyclization Reactions

The synthesis of the 5‐unsubstituted pyrido[3,2,1‐jk]carbazol‐6‐one 4 can be achieved by the reaction of carbazole ( 1 ) and malonate derivatives, either in a three‐step synthesis via 5‐acetyl‐pyridocarbazolone 3 or in a one‐step reaction from 1 and malonic acid/phosphoryl chloride. The 5‐acetyl derivative 5 can be transformed via a tosylate intermediate to 4‐azido‐pyridocarbazolone 11 , which cyclizes by thermal decomposition to the isoxazolo‐pyrido[3,2,1‐jk]carbazolone 12 . The thermolysis conditions were investigated by DSC. Nitration of pyridocarbazolone 4 and subsequent introduction of azide leads to azido derivative 23 , which cyclizes on thermolysis to furazan‐oxide derivative 24 . Again, the thermolysis conditions were investigated by DSC. 5‐Chloro‐5‐nitro‐pyrido[3,2,1‐jk]carbazole‐4,6‐dione, obtained from 4 by subsequent nitration and chlorination, forms by exchange of both 5‐substituents 5,5‐dihydroxy‐pyridocarbazoledione 17 , which acylates phenol to give 5‐hydroxy‐5‐(p‐hydroxyphenyl)‐pyridocarbazoledione 20 . Acid‐catalyzed cyclodehydration of 20 forms a highly fused benzofuro‐pyridocarbazole 21 . Another C–C coupling at position 5 starts from 4‐chloro‐5‐nitro‐pyridocarbazolone 22 and diethyl malonate 2a , which forms the diethyl (nitrocarbazolyl)malonate 25 . With dimethyl malonate 2c , the intermediate dimethyl (nitrocarbazolyl)malonate gives on thermolysis the (nitrocarbazolyl)acetate 27 by loss of one ester group.     

Synthesis and structure elucidation of 3,4‐dihydroxy‐2‐quinolin‐2‐ylpyrido[3,2,1‐jk]carbazol‐6‐ones

3,4‐Dihydroxy‐2‐quinolin‐2‐ylpyrido[3,2,1‐jk]carbazol‐6‐ones 6 were obtained by cyclocondensation of carbazole 1 with malonates 2 in the presence of quinoline. The assignment of the structures of 6 was performed by NMR experiments such as 1D ¹H, ¹³C and DEPT, as well as 2D COSY, HSQC, HMBC and 1,1‐ADEQUATE spectra.     

Synthesis and reactions of 10,10‐dimethyl‐10H‐pyrido[1,2‐a]indol‐6‐ones

Cyclocondensation of 2,3,3‐trimefhyl‐3H‐indoles 2 with malonates 3 gives 8‐hydroxy‐10,10‐dimefhyl‐10H‐pyrido[1,2‐a]indol‐6‐ones 4 , which were halogenated in position 7, 8 and 9 with sulfuryl chloride, bromine or phosphoroxychloride to give the corresponding halo‐10,10‐dimethyl‐10H‐pyrido[1,2‐a]indoles 5, 6, 7 and 8 . Amination affords the 8‐amino‐10,10‐dimethyl‐10H‐pyrido[1,2‐a]indol‐6‐one 9 . Nitration gives either the 10,10‐dimethyl‐7‐nitro‐10H‐pyrido[1,2‐a]indoles 10 or 10,10‐dimethyl‐7‐hydroxy‐10H‐pyrido[1,2‐a]indoles 11 , depending on the conditions.     

Synthesis of novel pyrido[3′,2′:5,6]thiopyrano[3,2‐b]indol‐5(6H)‐ones and 6H‐pyrido[3′,2′:5,6]thiopyrano[4,3‐b]quinolines,two new heterocyclic ring systems

The synthesis of new pyrido[3′,2′:5,6]thiopyrano[3,2‐b]indol‐5(6H)‐ones was accomplished by the Fischer‐indole cyclization of some 2,3‐dihydro‐3‐phenylhydrazonothiopyrano[2,3‐b]pyridin‐4(4H)‐ones, obtained from the 2,3‐dihydro‐3‐hydroxymethylenethiopyrano[2,3‐b]pyridin‐4(4H)‐one, by the Japp‐Klingemann reaction. 6H‐Pyrido[3′,2′:5,6]thiopyrano[4,3‐b]quinolines were obtained by reaction of 2,3‐dihydrothiopyrano‐[2,3‐b]pyridin‐4(4H)‐ones with o‐aminobenzaldehyde or 5‐substituted isatins. The preparation of some derivatives, functionalized with an alkylamino‐substituted side chain, is also described.     

Synthesis of Pyrazolo[3,4‐b]pyridin‐6‐ones

The procedures for the synthesis of substituted pyrazolo[3,4‐b]pyridine‐6‐ones and some of their properties are reviewed.     

Spiro[pyrido[3,2,1‐ij]pyrimido[4,5‐b]quinoline‐7,5′‐pyrrolo[2,3‐d]pyrimidines] and Spiro[pyrimido[4,5‐b]quinoline‐5,1′‐pyrrolo[3,2,1‐ij]quinolines] Derived from 5,6‐Dihydro‐4H‐pyrrolo[3,2,1‐ij]quinoline‐1,2‐dione

Reaction of 5,6‐dihydro‐4H‐pyrrolo[3,2,1‐ij]quinoline‐1,2‐dione ( 1 ) with two equivalents of some 6‐aminouracils (or 6‐amino‐2‐thiouracil) generates spirocyclic tetrahydrobenzo[if]quinolizines ( 7 ). The one‐pot, three‐component reaction of amido ketone ( 1 ) with 6‐aminouracil (or 6‐amino‐2‐thiouracil) and a cyclic six‐membered 1,3‐diketone produces spirocyclic tetrahydropyrrolo[3,2,1‐ij]quinolinones ( 15 ).     

Synthesis and reactions of 11H‐benzo[b]pyrano[3,2‐f]indolizines an pyrrolo[3,2,1‐ij]pyrano[3,2‐c]quinolines

2‐Methyl‐3H‐indoles 1 cyclize with two equivalents of ethyl malonate 2 to form 4‐hydroxy‐11H‐benzo[b]pyrano[3,2‐f]indolizin‐2,5‐diones 3, whereas 2‐mefhyl‐2,3‐dihydro‐1H‐indoles 9 give under similar conditions regioisomer 8‐hydroxy‐5‐methyl‐4,5‐dihydro‐pyrrolo[3,2,1‐ij]pyrano[3,2‐c]quinolin‐7,10‐diones 10 . The pyrone rings of 3 and 9 can be cleaved either by alkaline hydrolysis to give 7‐acetyl‐8‐hydroxy‐10H‐pyrido[1,2‐a]indol‐6‐ones 4 or 5‐acetyl‐6‐hydroxy‐2‐methyl‐1,2‐dihydro‐4H‐pyrrolo‐[3,2,1‐ij]quinolin‐4‐ones 11 , respectively. Chlorination of 3 and 9 with sulfurylchloride gives under subsequent ring opening 7‐dichloroacetyl‐8‐hydroxy‐10H‐pyrido[1,2‐a]indol‐6‐ones 5 or 5‐dichloracetyl‐6‐hydroxy‐2‐methyl‐1,2‐dihydro‐4H‐pyrrolo[3,2,1‐ij]quinolin‐4‐ones 12 . The dichloroacetyl group of 5 can be reduced with zinc to 7‐acetyl‐8‐hydroxy‐10H‐pyrido[1,2‐a]indol‐6‐ones 7. Treatment of the acetyl compounds 4, 7 and 11 with 90% sulfuric acid cleaves the acetyl group and yields 8‐hydroxy‐10H‐pyrido[1,2‐a]‐indol‐6‐ones 6 and 8 , and 6‐hydroxy‐2‐methyl‐1,2‐dihydro‐4H‐pyrrolo[3,2,1‐ij]quinolin‐4‐ones 13 . Reaction of dichloroacetyl compounds 12 with sodium azide yields 6‐hydroxy‐2‐methyl‐5‐(1H‐tetrazol‐5‐ylcarbonyl)‐1,2‐dihydro‐4H‐pyrrolo[3,2,1‐ij]quinolin‐4‐ones 14 via intermediate geminal diazides.     

Ring closure reactions of pyrido[2,3‐d]pyrimidines to pyrano[2′,3′:4,5]‐ and oxazolo[5′,4′:4,5]pyrido[2,3‐d]pyrimidines

The cyclocondensation of 5‐hydroxy‐pyrido[2,3‐d]pyrimidines 1 with malonates gives pyrano[2′,3′:4,5]‐pyrido[2,3‐d]pyrimidines 2 . Nitration of 1 and reduction with zinc in the presence of carboxylic acids/anhydrides gave 2‐alkyloxazolo[5′,4′:4,5]pyrido[2,3‐d]pyrimidines 4 , which were ring‐opened to 6‐aminopyrido[2,3‐d]pyrimidines 5, 6 and 7 . Cyclization of 6‐aminopyrido[2,3‐d]pyrimidines 6 with benzoylchlorides 8 gave 2‐aryloxazolo[5′,4′:4,5]pyrido[2,3‐d]pyrimidines 9 . Reaction conditions for the cyclization have been studied by differential scanning calorimetry (DSC).     

Synthesis of 1,4,5,6‐tetrahydropyrazolo[3,4‐d]pyrido[3,2‐b]azepine

The synthesis of 7,8‐dihydro‐5(6H)‐quinolinone ( 3 ) from commercially available 3‐amino‐2‐cyclohexen‐1‐one ( 1 ) and 3‐(dimethylamino)acrolein ( 4 ) in 23% yield avoids the preparation of propynal ( 2 ). Conversion of 5‐(4‐methylphenylsulfonyl)‐6,7,8,9‐tetrahydro‐5H‐pyrido[3,2‐b]azepine ( 12 ) to 6‐(4‐methylphenylsulfonyl)‐1,4,5,6‐tetrahydropyrazolo[3,4‐d]pyrido[3,2‐b]azepine ( 24 ) is described. Removal of the N‐(4‐methylphenylsulfonyl) group with 40% sulfuric acid in acetic acid gave the tricyclic azepine 26. Application of a similar series of reactions to 5‐(4‐nitrobenzoyl)‐6,7,8,9‐tetrahydro‐5H‐pyrido[3,2‐b]‐azepine ( 13 ) afforded 6‐(4‐nitrobenzoyl)‐1,4,5,6‐tetrahydropyrazolo[3,4‐d]pyrido[3,2‐b]azepine ( 25 ).     

Ring closure reactions of 3‐arylhydrazonoalkyl‐quinolin‐2‐ones to 1‐aryl‐pyrazolo[4,3‐c]quinolin‐2‐ones

4‐Hydroxy‐3‐arylhydrazonoalkyl‐2‐quinolones 6 or reactive derivatives such as 3‐arylhydrazonoalkyl‐4‐tosyloxy‐2‐quinolones 7 or 4‐chloro‐3‐arylhydrazonoalkyl‐2‐quinolones 14 , which are obtained via 3‐acyl‐4‐hydroxyquinolones 4, 10 or 3‐phenylarrmomethylene‐quinoline‐2,4‐diones 12 , cyclize in excellent yields to 1‐aryl‐pyrazolo[4,3‐c]quinolin‐4‐ones (11). The cyclization conditions were investigated by differential scanning calorimetry (DSC).     

Synthesis of pyrazolo[1,3,2]diazaphosphinin‐4‐ones

It was found that phosphinimidic isocyanates based on 3‐, 4‐, and 5‐aminopyrazoles could undergo intramolecular heterocyclization to yield previously unknown pyrazolo[1,3,2]diazaphosphorin‐4‐ones containing an endocyclic PN double bond. It was shown that phosphinimidic isocyanate based on 4‐aminopyrazole, in which there are two positions (3 and 5) available for the cyclization, reacts exclusively at the 5‐carbon atom. © 2012 Wiley Periodicals, Inc. Heteroatom Chem 23:210–215, 2012; View this article online at wileyonlinelibrary.com . DOI 10.1002/hc.21005     

The Production and Characterisation of Novel Conducting Redox‐Active Oligomeric Thin Films From Electrooxidised Indolo[3,2,1‐jk]carbazole

Novel thin‐film materials have been produced from indolo[3,2,1‐jk]carbazole (see picture). These are conducting and redox‐active and, unusually, consist of three distinct covalently coupled luminescent dimer species, consistent with a specific radical‐cation coupling mechanism.

     

Synthesis of new benzo[h]‐ and benzo[f]chromeno[2,3‐b]‐pyridine‐5‐ones

A number of new benzo[h]‐ and benzo[f]chromeno[2,3‐b] pyridine‐5‐ones derivatives were synthesized from benzo[h]‐ and benzo[f]‐chromone‐carbonitriles and amino‐benzo[h]‐ and benzo[f]chromone‐carbaldehydes. © 2006 Wiley Periodicals, Inc. Heteroatom Chem 17:2–7, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20152     

Furan ring opening ‐ indole ring closure: Synthesis of furo[2′,3′:3,4]‐cyclohepta[1,2‐b]indolium chlorides

A new synthetic approach to furo[2′,3′:3,4]cyclohepta[1,2‐b]indolium chlorides is elaborated starting from 2‐acetylaminoaryldifurylmethanes or 2‐aminoaryldifurylmethanes under treatment with methanolic HCl solution. The reaction proceeds in three steps: recyclization, intramolecular cyclization, and disproportionation. In this case the furan ring takes part in building up both pyrrole and seven‐membered rings. The same salts can be obtained directly from 2‐acetylaminobenzaldehydes and 2‐methylfuran under similar conditions without isolation of corresponding 2‐acetylaminoaryldifurylmethanes.