The Synthesis of Novel Polycyclic Heterocyclic Ring Systems via Photocyclization. 12. Benzo[h]naphtho-[2′,1′:4,5]thieno[2,3-c]quinoline and benzo[f]-naphtho[2′,1′:4,5]thieno[2,3-c]quinoline

The synthesis of two previously unknown heterocyclic ring systems, namely benzo[h]naphtho[2′,1′:4,5]thi-eno[2,3-c]quinoline (1) and benzo[f]naphtho[2′,1:4,5]thieno[2,3-c]quinoline (2) was accomplished via photocyclization of the appropriate amides followed by chlorination and catalytic dechlorination. The total assignment of ¹H and ¹³C nmr spectra of 2 was determined utilizing two-dimensional nmr methods, providing unequivocal structural proof of the two novel polycyclic ring systems.     

The synthesis of novel polycyclic heterocyclic ring systems via photocyclization. 4 . Benzo[f]thieno[2′,3′:4,5]thieno[2,3-c]quinoline and Benzo[h]thieno[2′,3′:4,5]thieno[2,3-c]quinoline and the total assignment of their 1H- and 13C-NMR spectra

The synthesis of two novel polycyclic heterocyclic ring systems via photocyclization are reported. These are benzo[f]thieno[2′,3′:4,5]thieno[2,3-c]quinoline and benzo[A]thieno-[2′,3′:4,5]thieno[2,3-c]quinoline. The total assignment of their ¹H- and ¹³C-nmr spectra was determined by utilizing two-dimensional nmr spectroscopic methods.     

The synthesis of novel polycyclic heterocyclic ring system via photocyclization. 18. Benzo[h]naphtho-[1′,2′:4,5]thieno[2,3-c]quinoline and benzo[h]naphtho-[1′,2′:4,5]thieno[2,3-c] [1,2,4]triazolo[4,3-a]quinoline

The synthesis of two previously unknown polycyclic ring systems, benzo[h]naphtho[1′2′:4,5]-thieno[2,3-c]quinoline ( 1 ) and benzo[h]naphtho[1′,2′:4,5]thieno[2,3-c][1,2,4]triazolo[4,3-a]quinoline ( 2 ), was achieved via oxidative photocyclization of 1-chloro-N-(1-naphthyl)naphtho[2,1-b]thiophene-2-carboxamide ( 5 ). The total assignment of their ¹H and ¹³C nmr spectra was determined by the concerted use of two-dimensional nmr methods.     

Synthesis of two novel ring systems via photocyclization: Thieno[2′,3′:4,5]thieno[2,3-c][1,10]phenanthroline and thieno[3′,2′:4,5]thieno[2,3-c][1,10]phenanthroline

The synthesis of thieno[2′,3′:4,5]thieno[2,3-c][1,10]phenanthroline ( 5 ) and thieno[3′,2′:4,5]thieno-[2,3-c][1,10]phenanthroline ( 10 ) are described. Each compound was obtained in four steps from known starting materials. The basic skeleton of the molecule and of the phenanthroline ring were formed via photocyclization. The total assignment of ¹H-nmr spectra was accomplished with the aid of two-dimensional nmr methods.     

The synthesis of novel polycyclic heterocyclic ring systems. 3. Synthesis and NMR spectroscopy of 15-chloro[1]benzo-thieno[2″,3″:3′,4′]naphtho[1′,2′:4,5]thieno[2,3-c]quinoline

The polycyclic heterocyclic compound with a novel ring system, 15-chloro[1]benzothieno[2″,3″:3′,4′]-naphtho[1′,2′:4,5]thieno[2,3-c]quinoline was synthesized via photocyclization of 3-chloro-N-phenyl[1]-benzothieno[2′,3′:3,4]naphtho[2,1-b]fhiophene-2-carboxamide followed by chlorination with phosphorus oxychloride. The assignment of its ¹H and ¹³C nmr spectra was accomplished by utilizing two-dimensional nmr methods.     

The synthesis of novel polycyclic heterocyclic ring systems via photocyclization. 1. Thieno[3′,2′:4,5]thieno[2,3-c]quinoline and thieno[2′,3′:4,5]thieno[2,3-c]quinoline

The synthesis of two previously unknown heterocyclic ring systems, namely, thieno[3′,2′:4,5]thieno[2,3-c]-quinoline and thieno[2′,3′:4,5]thieno[2,3-c]quinoline is reported. These two novel ring systems were assembled by photocyclization of the appropriate anilides.     

The synthesis of novel polycyclic heterocyclic ring systems via photocyclization. 9. Phenanthro[9′,10′:4,5]thieno[2,3-c]quinoline,benzo[f]phenanthro[9′,10′:4,5]thieno[2,3-c]quinoline,and benzo[h]-phenanthro[9′,10′:4,5]thieno[2,3-c]quinoline

The synthesis of three novel polycyclic heterocyclic ring systems are reported via photocyclization. The specific final products in these ring systems are: phenanthro[9′,10′:4,5]thieno[2,3-c]quinoline ( 13 ), benzo[h]-phenanthro[9′,10′:4,5]thieno[2,3-c]quinoline ( 14 ), and benzo[f]phenanthro[9′,10′:4,5]thieno[2,3-c]quinoline ( 15 ).     

Synthesis and total 1H-NMR assignment of naphtho[1′,2′:4,5]thieno[2,3-c][1,10]phenanthroline and naphtho[2′,1′:4,5]-thieno[2,3-c] [1,10]phenanthroline

Naphtho[1′,2′:4,5]thieno[2,3-c][1,10]phenanthroline and naphtho[2′,1′:4,5]thieno[2,3-c][1,10]phenanthroline, two novel polycyclic heterocyclic ring systems, have been synthesized in four steps from known starting materials. The total ¹H nmr spectral assignments were made using a COSY experiment to identify the spin systems.     

The synthesis of novel polycyclic heterocyclic ring systems via photocyclization. 13. Dibenzo-[f,h]phenanthro[9′,10′:4,5]thieno[2,3-c]quinoline

The synthesis of a previously unknown polycyclic heterocyclic ring system, dibenzo[f,h]phenanthro-[9′,10′:4,5]thieno[2,3-c]quinoline ( 4 ), was accomplished via photocyclization of the appropriate amide followed by chlorination. Substitution of the chlorine atom with hydrazine followed by removal of the hydrazine moiety with 10% copper sulfate solution afforded the parent ring system 4 . The unequivocal assignment of its highly congested ¹H and ¹³C spectra was accomplished by utilizing two-dimensional nmr methods.     

The synthesis of monomethoxynaphtho[1′,2′:4,5]thieno[2,3-c]quinolines

A series of monomethoxynaphtho[1′,2′:4,5]thieno[2,3-c]quinolines has been prepared by photocyclization of the appropriate N-methoxyphenyl-1-chloronaphtho[2,1-b]thiophene-2-carboxamides. Some of the lactams obtained were converted into the thiolactams and their S-methyl derivatives. The lactams were also converted into the corresponding 6-chloro derivatives. Some of these were catalytically dechlorinated into the monomethoxynaphtho[1′,2′:4,5]thieno[2,3-c]quinolines which were then quaternized into the N-methyl quaternary salts.     

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 .     

The synthesis of novel polycyclic heterocyclic ring systems via photocyclization. 17. Thieno[3′,2′:4,5]thieno[2,3-c]naphtho-[2,1-f]quinoline and thieno[3′,2′:4,5]thieno[2,3-c]-naphtho[1,2-g]quinoline

The synthesis of two previously unknown novel polycyclic heterocyclic ring systems via photocyclization is described. The structural assignment of the isomeric ring systems, 4 and 5 , was achieved by the total assignment of their ¹H and ¹³C nmr spectra by the concerted usage of two-dimensional nmr methods.     

The synthesis of novel polycyclic heterocyclic ring systems via photocyclization. 23 . Naphtho[2′,1′:4,5]thieno‐[2,3‐c]naphtho[2,1‐f]quinoline

A previously unknown heterocyclic ring system, naphtho[2′,1′:4,5]thieno[2,3‐c]naphtho[2,1‐f]quinoline ( 14 ), was synthesized via oxidative photocyclization of 3‐chloro‐N‐(2‐phenanthryl)naphtho[1,2‐b]‐thiophene‐2‐carboxamide ( 9 ). Further elaboration of the lactam 10 yielded the unsubstituted ring system 14 . Structural confirmation of compound 14 was accomplished by a total assignment of its ¹H and ¹³C nmr spectra utilizing the concerted two‐dimensional nmr spectroscopic methods.     

Synthesis and S-methylation of 2-thioxopyrido[3′,2′:4,5]thieno[3,2-d]-pyrimidin-4(3H)-ones with and without a phase transfer catalyst

A number of 2-thioxopyrido[3′,2′:4,5]thieno[3,2-H]pyrimdin-4(3H-ones (5) have been synthesized by cyclocondensation of 2-carbethoxy-3-amino-4-phenyl-6-substituted-thieno[2,3-b]pyridines (3) with various isothiocyanates. Compounds 5 were S-methylated routinely and the reactions compared under solid-liquid phase transfer conditions to obtain 2-methylthiopyrido[3′,2′:4,5]thieno[3,2-d]pyrimidin-4(3H)-^ones (6). The new triheterocyclic pyridothienopyrimidines were prepared with the objective to study their pharmacological properties.     

Fusions of pyrido[4′,3′:4,5]thieno[2,3-d]pyrimidines with N-heterocyclic moieties

Versatile 2-thioxopyrimidine-type building blocks ethyl 3-(2-ethoxy-2-oxoethyl)- 4 -oxo-2-thioxo-1,2,3,4,5,6,7,8-octahydropyrido[4′,3′:4,5]thieno[2,3-d]pyrimidine-7-carboxylate ( 4 ) and ethyl 4-oxo-2-thioxo-1,2,3,4,5,6,7,8-octahydropyrido[4′,3′:4,5]thieno[2,3-d]pyrimidine-7-carboxylate ( 8 ) were synthesized from diethyl 2-amino-4,5,6,7-tetrahydrothieno[2,3-c]pyridine-3,6-dicarboxylate ( 1 ). Derivatives of linear and angular heterocyclic systems having the imidazole and 1,2,4-triazole ring were obtained from the key intermediates 4 and 8 , respectively.     

Studies of thieno[2,3-b]pyrazines in preparation of pyrazino[2′,3′:4,5]thieno[3,2-d]pyrimidines and related molecules

A variety of 2,3-disubstituted derivatives of the previously unknown thieno[2,3-b]pyrazine ring system have been employed as a synthetic foundation for pyrazino[2′,3′:4,5]thieno[3,2-d]-pyrimidine and several of its derivatives.     

Nitration of dithieno[3,4-b:3′,2′-d]pyridine and dithieno[2,3-b:3′,2′-d]pyridine

The nitration of dithieno[3,4-b:3′,2′-d]pyridine ( 2 ) and dithieno[2,3-b:3′,2′-d]pyridine ( 3 ) has been studied. Nitration of 2 occurred in both positions of the c-fused thiophene ring, while 3 was predominantly substituted in the 2-position. The structures of the nitro derivatives were proven by extensive use of ¹H and ¹³C nmr spectroscopy.     

The synthesis of novel polycyclic heterocyclic ring systems via photocyclization. 5. [1]Benzothieno[2,3-c]naphtho[2,1-f]-quinoline and [1]benzothieno[2,3-c]naphtho[1,2-g]quinoline

Two previously unknown heterocyclic ring systems, namely, [1]benzothieno[2,3-c]naphtho[2,1-f]quinoline ( 4 ) and [1]benzothieno[2,3-c]naphtho[1,2-g]quinoline ( 5 ) were synthesized via photocyclization of 3-chloro-N-(2-phenanthryl)benzo[b]thiophene-2-carboxamide ( 8 ) followed by chlorination and dechlorination. The total assignment of their ¹H- and ¹³C-nmr spectra was determined by utilizing inverse-detected HMQC and HMBC two-dimensional nmr spectroscopic methods.     

Pyrido[2′1′:2,3]imidazo[4,5-c]isoquinoline and the alkylation of pyrido[2′,1′:2,3]imidazo[4,5-c]isoquinolin-5(6H)-one

The reaction of 2-aminopyridine, o-phthaldehydic acid and potassium cyanide gave pyrido[2′,1′:2,3]imidazo[4,5-c]isoquinolin-5(6H)-one, which upon treatment with propargylbromide, yielded both O and N alkylated products. 2-Aminopyridine, o-phthaldehyde and potassium cyanide gave 1-cyano-2-(2-pyridyl)isoindole which rearranged in acid to give the previously unreported parent pyrido[2′,1′:2,3]imidazo[4,5-c]isoquinole. Structures were confirmed using uv, ir, nmr and x-ray spectroscopy.     

Synthesis of novel pyrido[3′,2′:4,5]thieno[3,2‐d]pyrimidines,pyrido[3″,2″:4′,5′]thieno[3′,2′:4,5]pyrimido[l,6‐a]benzimidazoles and related fused systems

3‐Amino‐4‐aryl‐5‐ethoxycarbonyl‐6‐methylthieno[2,3‐b]pyridine‐2‐carboxamides 3a‐c were prepared from ethyl 4‐aryl‐3‐cyano‐6‐methyl‐2‐thioxo‐1,2‐dihydropyridine‐5‐carbonylates 1a‐c and reacted with some carbonyl compounds to give tetrahydropyridothienopyrimidine derivatives 6a‐c, 7a‐c and 8a‐c , respectively. Treatment of compound 3c with chloroacetyl chloride led to the formation of a next key compound, ethyl 2‐chloromethyl‐4‐oxo‐3,4‐dihydropyrido[3′,2′:4,5]thieno[3,2‐d]pyrimidine‐8‐carboxylate 9 . Also, 3‐amino‐2‐benzimidazolylthieno[2,3‐b]pyridine‐5‐carboxylate 5 and 2‐(3′‐aminothieno [2,3‐b]pyridin‐2′‐yl)‐4‐oxo‐3,4‐dihydropyrido[3′,2′:4,5]thieno[3,2‐d]pyrimidine‐8‐carboxylate 17 were prepared from 1c. The compounds 5, 9 and 17 were used as good synthons for other pyridothienopyrimidines and pyridothienopyrimidobenzimidazoles as well as for related fused polyheterocyclic systems.