A facile synthesis of enol type acyl cyanides via a 1,3-dipolar cycloaddition reaction and a cyano group migration

The reaction of 7-chlorotetrazolo[1,5-a]quinoxaline 5-oxide 4a or 7-chloro-1,2,4-triazolo[4,3-a]quinoxaline 5-oxide 4b with 2-chloroacrylonitrile gave 7-chloro-4-(2-cyano-2-hydroxyvinyl)tetrazolo[1,5-a]quinoxaline 5a or 7-chloro-4-(2-cyano-2-hydroxyvinyl)-1,2,4-triazolo[4,3-a]quinoxaline 5b , respectively. Alcoholysis of compound 5a or 5b afforded 7-chloro-4-ethoxycarbonylmethylene-4,5-dihydrotetrazolo[1,5-a]quinoxaline 6a or 7-chloro-4-ethoxycarbonylmethylene-4,5-dihydro-1,2,4-triazolo[4,3-a]quinoxaline 6b , respectively. Compounds 5a,b were found to exist as a syn and anti mixture of the enol form, while compounds 6a,b occurred as the enamine and methylene imine forms. The tautoraeric character and/or D-H exchange of the vinyl protons are described for compounds 5a,b and 6a,b .     

NMR study on the tautomeric equilibria between the hydrazone imine and diazenyl enamine forms in side chained quinoxalines: Solvent effects and temperature dependence

The reaction of 7-chloro-4-ethoxycarbonylmethylene-4,5-dihydro-1,2,4-triazolo[4,3-a]quinoxaline 6 with 4-ethoxycarbonyl-1-methyl-1H-pyrazole-5-diazonium chloride or 4-cyano-1,3-dimethyl-1H-pyrazole-5-diazonium chloride gave 7-chloro-4-[α-(4-ethoxycarbonyl-1-methyl-1H-pyrazol-5-ylhydrazono)-ethoxycarbonylmethyl]-1,2,4-triazolo[4,3-a]quinoxaline 8a or 7-chloro-4-[α-(4-cyano-1,3-dimethyl-1H-pyrazol-5-ylhydrazono)ethoxycarbonylmethyl]-1,2,4-triazolo[4,3-a]quinoxaline 8b , respectively, while the reaction of 7-chloro-4-ethoxycarbonylmethylene-4,5-dihydrotetrazolo[1,5-a]quinoxaline 7 with 4-ethoxycarbonyl-1-methyl-1H-pyrazole-5-diazonium chloride or 4-cyano-1,3-dimethyl-1H-pyrazole-5-diazomum chloride provided 7-chloro-4-[α-(4-ethoxycarbonyl-1-methyl-1H-pyrazol-5-ylhydrazono)ethoxycarbonylmethyl]tetrazolo[1,5-a]quinoxaline 9a or 7-chloro-4-[α-(4-cyano-1,3-dimethyl-1H-pyrazol-5-ylhydrazono)ethoxycarbonylmethyl]tetrazolo[1,5-a]quinoxaline 9b , respectively. Compounds 8a,b and 9a,b showed the tautomeric equilibria between the hydrazone imine C and diazenyl enamine D forms in dimethyl sulfoxide and/or trifluoroacetic acid, and the effects of solvent and temperature on the tautomer ratios of C to D were studied by the nmr measurements in a series of mixed trifluoroacetic acid/dimethyl sulfoxide media (compounds 8a,b and 9a,b ) and at various temperatures (compounds 8a,b ).     

Reaction of azole condensed quinoxaline N-oxides with acetic anhydride

The reaction of 7-chlorotetrazolo[1,5-α]quinoxaline 5-oxide 6a with acetic anhydride gave 7-chloro-5-(7-chlorotetrazolo[1,5-α]quinoxalin-4-yl)-4,5-dihydro-4-oxotetrazolo[1,5-α]quinoxaline 7a , while the reaction of 7-chloro-1,2,4-triazolo[4,3-α]quinoxaline 5-oxide 6b with acetic anhydride afforded 7-chloro-5-(7-chloro-1,2,4-triazolo[4,3-α]quinoxalin-4-yl)-4,5-dihydro-4-oxo-1,2,4-triazolo[4,3-α]quinoxaline 7b and 7-chloro-4,5-dihydro-4-oxo-1,2,4-triazolo[4,3-α]quinoxaline 8b . The reaction of compound 6a or 6b with acetic anhydride/acetic acid provided 7-chloro-4,5-dihydro-4-oxo-tetrazolo[1,5-α]quinoxaline 8a or compound 8b , respectively.     

Synthesis of mesoionic triazolo[4,3-a]quinoxalines

The reaction of 6-chloro-2-(1-methylhydrazino)quinoxaline 4-oxide 1 or 6-chloro-2-(1-methylhydrazino)-quinoxaline 5 with phenyl isothiocyanate under reflux in N,N-dimethylformamide gave 7-chloro-3-methyl-1,2,4-triazolo[4,3-a]quinoxalin-3-ium-1-thioate 4 , which was also obtained by refluxing of 6-chloro-2-[1-methyl-2-(N-phenylthiocarbamoyl)hydrazino]quinoxaline 4-oxide 2b or 6-chloro-2-[1-methyl-2-(N-phenylthiocarbamoyl)hydrazino]quinoxaline 6 in N,N-dimethylformamide.     

Synthèse et étude physicochimique des 1,2,4-triazolo[4,3-a]-pyridines et des 1,2,4-triazolo[2,3-a]pyridines

The synthesis of 1,2,4-triazolo[4,3-a] and [2,3-a]pyridines 7, 8 was achieved by cyclization of 2-hydrazino-8-nitropyridine 3a with formic acid. The 4,5,6,7-tetrahydro-1,2,4-triazolo[2,3-a]pyridine 13 and 8-amino-1,2,4-triazolo[2,3-a]pyridine 9 were obtained by catalytic hydrogenation. The reduction of triazolo pyridine 8 using stannous chloride led to the intermediate compound 10 which with acetic anhydride afforded 8-acetylamino-5-chloro-1,2,4-triazolo[2,3-a]pyridine 10a . The structure of the derivatives was determined by ¹H-nmr (DMSO-d₆).     

Synthesis of 1-hydrazinopyridazino[4,5-b]quinoxaline and related compounds

This paper describes the synthesis of 1-hydrazinopyridazino[4,5-b]quinoxaline ( 10 ), tetrazolo[4,3-b]pyridazino[4,5-b]quinoxaline ( 11 ) and some 1,2,4-triazolo[4,3-b]pyridazino[4,5-b]quinoxalines 13 . Starting with 2-ethoxycarbonyl-3-methylquinoxaline 1,4-dioxide ( 1 ), 1,2-dihydro-1-oxopyridazino[4,5-b]quinoxaline ( 5 ) was prepared by three different ways: (a) chlorination of 1 in acetic acid gave 2-ethoxycarbonyl-3-dichloromethylquinoxaline 1,4-dioxide, which reacts with an excess of hydrazine to give about 60% of 5 ; (b) oxidation of 1 with selenium dioxide gave 90% of 2-ethoxycarbonyl-3-formylquinoxaline 1,4-dioxide ( 3 ), which reacts with hydrazine to give 5 (63%); (c) compound 3 was treated with hydrazine to give 1,2-dihydro-1-oxopyridazino-[4,5-b]quinoxaline 1,4-dioxide ( 4 ) (70%), which by reduction with sodium dithionite gave 5 (80%). Compound 5 reacts with phosphorus pentasulfide or the Lawesson reagent to give 1,2-dihydro-1-thiocarbonylpyridazino[4,5-b]quinoxaline ( 9 ), which treated with hydrazine gave 5 (80%). This last compound reacts with nitrous acid to give 11 . Some hydrazones 12 from 10 are described. Heating the aldehyde hydrazones 12a,c,d with dimethylsulfoxide some 1,2,4-triazolo[4,3-b]pyridazino[4,5-b]quinoxalines 13 were obtained. Compound 13a was also obtained in the reaction of 10 with benzoyl chloride. Reaction of 3 with phenylhydrazine gave 1,2-dihydro-1-oxo-2-phenylpyridazino[4,5-b]quinoxaline ( 6 ). Reactions of 5 with acetic anhydride and dimethylsulfate gave, respectively, 1-acetoxypyridazino[4,5-b]quinoxaline ( 8 ) and 1,2-dihydro-1-oxo-2-methylpyridazino-[4,5-b]quinoxaline ( 7 ). All the compounds were characterized by elemental analysis and ¹H-nmr spectra. Compounds 5 and 10 showed antihypertensive activity in rats.     

The synthesis of 11H-1,2,4-triazolo[4,3-b]pyridazino[4,5-b]indoles,11H-tetrazolo[4,5-b]pyridazino[4,5-b]indoles and 1,2,4-triazolo[3,4-f]-1,2,4-triazino[4,5-a]indoles

This paper describes the synthesis of the previously unknown 11H-1,2,4-triazolo[4,3-b]pyridazino[4,5-b]indoles (2) and 11H-tetrazolo[4,5-b]pyridazino[4,5-b]indoles (3) from 4-hydrazino-5H-pyridazino[4,5-b]indoles (1) , as well as the synthesis of 1,2,4-triazolo[3,4-f]-1,2,4-triazino-[4,5-a]indoles (10) from 2-indolecarbohydrazide (4) . Compounds 2 were obtained by acylation of compounds 1 , followed of thermal cyclization and compounds 3 by treating compounds 1 with nitrous acid. The reactions of compound 4 with formic acid or ethyl orthoformiate gave 1,2-dihydro-1-oxo-1,2,4-triazino[4,5-a]indole (6) . Treating this last compound with phosphorus oxychloride or phosphorus pentasulfide, followed by hydrazine, gave 1-hydrazino-1,2,4-triazino-[4,5-a]indole (9) . Acylation of this last compound, followed of cyclization gave compounds 10 . All the compounds were characterized by elemental analysis and ir and ¹H-nmr spectra.     

Reaction of 1-hetaryl-4-phenylthiosemicarbazides with <Emphasis Type="Italic">N,N′</Emphasis>-dicyclohexylcarbodiimide

1,2,4-Triazolo[3,4-b][1,3]benzothiazole, 1,2,4-triazolo[4,3-a]pyrimidine, and thieno[3,2-e][1,2,4]-triazolo[4,3-a]pyrimidine derivatives were synthesized by reactions of 1-hetaryl-4-phenylthiosemicarbazides with N,N′-dicyclohexylcarbodiimide.     

An influence of a basic side chain moiety on the tautomer ratio between the enamine and methylene imine forms in azole condensed quinoxalines

The reaction of 7-chloro-4-(2-cyano-2-hydroxyvinyl)tetrazolo[1,5-α]quinoxaline 2a with 4-aminopyridine, p-toluidine or p-aminophenol gave 7-chloro-4-(4-pyridylcarbamoylmethylene)-4,5-dihydrotetrazolo[1,5-α]-quinoxaline 7a , 7-chloro-4-(p-tolylcarbamoylmethylene)4, 5-dihydrotetrazolo[1,5-α]quinoxaline 8a or 7-chloro-4-(p-hydroxyphenylcarbamoylmethylene)-4,5-dihydrotetrazolo[1,5-α]quinoxaline 9a , respectively. The reaction of 7-chloro-4-(2-cyano-2-hydroxyvinyl)-1,2,4-triazolo[4,3-α]quinoxaline 2b with 4-aminopyridine, p-toluidine or p-aminophenol afforded 7-chloro4-(4-pyridylcarbamoylmethylene)-4,5-dihydro-1,2,4-triazolo-[4,3-α]quinoxaline 7b , 7-chloro-4-(p-tolylcarbamoylmethylene)-4,5-dihydro-1,2,4-triazolo[4,3-α]quinoxaline 8b or 7-chloro-4-(p-hydroxyphenylcarbamoylmethylene)-4,5-dihydro-1,2,4-triazolo[4,3-α]quinoxaline 9b , respectively. The reaction of compound 2a with 2-aminopyridine or 3-aminopyridine provided 7-chloro-4-(2-pyridyl-carbamoylmethylene)-4,5-dihydrotetrazolo[1,5-α]quinoxaline 10 or 7-chloro-4-(3-pyridyl-carbamoylmethylene)-4,5-dihydrotetrazolo[1,5-α]quinoxaline 11 , respectively. Compounds 7a,b (4-pyridylcarbamoyl) predominated as the enamine tautomer A in a trifluoroacetic acid solution, while compounds 8a,b (p-tolylcarbamoyl) and compounds 9a,b (p-hydroxyphenylcarbamoyl) coexisted as the enamine A and methylene imine B tautomers in a trifluoroacetic acid solution. Moreover, the ratio of the enamine tautomer A elevated in an order of compound 11 (3-pyridylcarbamoyl), compound 10 (2-pyridylcarbamoyl) and compound 7a (4-pyridylcarbamoyl), reflecting an order of the increase in the pKa values of the aminopyridine side chain moieties. In general, the ratio of the enamine tautomer A was higher in the basic carbamoyl derivatives 7–11 than in the neutral ester derivatives 3a,b . From these results, the basic side chain moiety of the tetrazolo[1,5-α]quinoxalines 7a-11 or 1,2,4-triazolo[4,3-α]quinoxalines 7b-9b was found to increase the ratio of the enamine tautomer A in trifluoroacetic acid media.     

Synthesis of some new derivatives of 4-hydrazino-5H-pyridazino[4,5-b]indole

This paper describes the synthesis of 1-chloro-4-hydrazino-5H-pyridazino[4,5-b]indole ( 4 ) and some of the triazoles ( 6–8 ), tetrazoles ( 10–11 ), triazolotetrazoles ( 9 ) and bis-tetrazoles ( 12 ) derived from it. All of these were previously unknown compounds. Treating 1,4-dioxo-1,2,3,4-tetrahydro-5H-pyridazino[4,5-b]indole ( 1 ) with phosphorus oxychloride gave 1,4-dichloro-5H-pyridazino[4,5-b]indole ( 2 ), which reacts regioselectively with hydrazine to give compound 4 . The reactions of 4 with formic and acetic acids gave 6-chloro-11 H-1,2,4-triazolo[4,3-b]pyridazino[4,5-b]indoles ( 6a-6b ), respectively. Reaction of compound 6a with hydrazine gave 6-hydrazino-11H-1,2,4-triazolo[4,3–6]-pyridazino[4,5,-b]indole ( 8 ). This with nitrous acid gave 6-azido-11H-1,2,4-triazolo[4,3-b]pyridazino[4,5-b]-indole ( 9 ). Compound 4 reacted with nitrous acid to give 6-chloro-11H-tetrazolo[4,5-b]pyridazino[4,5-b]-indole ( 10 ), which gave 1,4-diazydo-5H-pyridazino[4,5-b]indole ( 12 ), through successive reactions with hydrazine and nitrous acid. All compounds were characterized by elemental analysis, ir and ¹H-nmr spectra.     

Synthesis and reactivity of 1,2,4-triazolo[1,5-c]quinazolines

The preparation of 1,2,4-triazolo[1,5-c]quinazolines 4a-d , 5 , 8a-d by cyclocondensation of 1a-c with carboxylic acids and carboxylic anhydrides, respectively, is described. By different pathways, the 5-thioxo-5,6-dihydro-1,2,4-triazolo[1,5-c]quinazolines 4a-d react with hydrazine hydrate or amines with the formation of 5-substituted 1,2,4-triazolo[1,5-c]quinazolines 9 and 10a-d . Cyclocondensation of 9 with carboxylic acids, carboxylic anhydrides, and nitrous acid, respectively, leads to the new anellated heterocycles bis-1,2,4-triazolo[4,3-a:1,5-c]quinazoline 13 and tetrazolo [1,5-a]-1,2,4-triazolo[1,5-c]quinazoline ( 14 ).     

The photo cycloaddition of alkenes to s-triazolo[4,3-b] and [2,3-b]pyridazines

s-Triazolo[4,3-b]pyridazine (I) reacted with cyclohexene under the influence of ultraviolet light to yield 4a,5,7,8,8a,9-hexahydro-9-methylene-6H-s-triazolo[1,5-a]indole (IV) and 9-cyanomethyl-4a,5,7,8,8a,9-hexahydro-6H-s-triazolo[1,5-a]indole (V). These products were formed by the addition of the alkene to the 1,8 positions of I with a concurrent cleavage of the N₄? N₅ bond. Similar additions were observed with cyclopentene and 2,3-dimethyl-1,3-butadiene. The isomeric s-triazolo[2,3-b]pyridazine (III) reacted with cyclohexene to form an isomer of IV, 4a,5,7,8,8a,9-hexahydro-9-methylene-6H-s-triazolo[4,3-a]indole (XV) and two [2 + 2] cycloadducts (XVI and XVII).     

Selenium Dioxide–Mediated Synthesis of Fused 1,2,4-Triazoles as Cytotoxic Agents

A series of fused 1,2,4-triazoles has been prepared by oxidative intramolecular cyclization of heterocyclic hydrazones with selenium dioxide. General applicability of this practical protocol was confirmed by the synthesis of moderate to good yields of 1,2,4-triazolo[4,3-a]pyridines, 1,2,4-triazolo[4,3-a]pyrimidines, 1,2,4-triazolo[4,3-a]pyramidines, and 1,2,4-triazolo-[4,3-a]quinoxa lines. All compounds were tested in vitro for their cytotoxic activity against HCT-116, A549, and Colo-205 cell lines. Two compounds, 3-(4-methoxyphenyl)-7-methyl-[1,2,4]triazolo[4,3-a]pyridine and 1-(4-methoxyphenyl)-[1,2,4]triazolo[4,3-a]quinoxaline, showed potent antiproliferative activity against the three cell lines.     

A Convenient Synthesis of NovelDerivatives of Pyrido[2,3- d ][1,2,4]triazolo[4,3- a ]pyrimidine-5,6-dione

 Reaction of 6-Amino-2-thiouracil with hydrazonoyl halides yielded regioselectively 7-amino-1,3-disubstituted-1,2,4-triazolo[4,3-a]pyrimidine derivatives. Upon treatment with methyl (Z)-2-benzoylamino-3-dimethylaminopropenoate, the corresponding methyl (Z)-2-benzoylamino-3-([1,2, 4]triazolo[4,3-a]pyrimidin-7-yl)-amino propenoates were obtained which cyclized in the presence of sodium ethoxide to afford novel derivatives of pyrido[2,3-d][1,2,4]triazolo[4,3-a]pyrimidine-5,6-(1H,8H)-diones.     

New heterocyclic structures. [1,3]Thiazino[3,2-a]purine and [1,2,3]triazolo[4,5-d][1,3]thiazino[3,2-a]pyrimidine

Derivatives of two new molecular structures, namely, [1,3]thiazino[3,2-a]purine and [1,2,3]triazolo[4,5-d]-[1,3]thiazino[3,2-a]pyrimidine, were synthesized together with other heterocyclic compounds. Retrosynthetic analysis of their molecular skeletons suggested a simple way of obtaining 3,4-dihydro-7,8-diamino-2H,6H-pyrimido[2,1-b][1,3]thiazin-6-one, which is a useful intermediate for their synthesis. This intermediate and the thiazole homologue were obtained directly by reaction of 5,6-diamino-2,3-dihydro-2-thioxo-4(lH)-pyrimidi-none with 1,3- or 1,2-dibromoalkane, respectively.     

Preparation of 5-substituted- and 3,5-disubstituted-s-triazolo[4,3-a]pyridines

Cyclization of N-acyl-N′-(6-chloropyrid-2-yl)hydrazines ( 2a-2e ) with phosphorus oxychloride has produced several 5-chloro-s-triazolo[4,3-a]pyridines ( 3a-3e ). Nucleophilic displacement of the chlorosubstituent of 5-chloro-s-triazolo[4,3-a]pyridine ( 3a ) availed the 5-ethoxy ( 4a ) and 5-thioethoxy ( 4b ) derivatives and di(s-triazolo[4,3-a]pyrid-5-yl)sulfide ( 8 ) while reaction of 5-ethylsulfonyl-s-triazolo[4,3-a]pyridine ( 4d ) with potassium hydroxide yielded the 5-hydroxy/5-one system ( 4c or 6 ). Further reaction of 3a with bromine to give 3-bromo-5-chloro-s-triazolo-[4,3-a]pyridine ( 3g ) has provided the corresponding 3-cyano- and 3-carboxamido-5-chloro-s-triazolo[4,3-a]pyridine derivatives ( 3h and 3i ). Treatment of 6-chloro-2-hydrazinopyridine ( 1 ) with cyanogen bromide has provided 3-amino-5-chloro-s-triazolo[4,3-a]pyridine ( 3f ) which, with bromoacetaldehyde dimethyl acetal, transformed into 7-chloroimidazo[1,2-b]-s-triazolo[4,3-a]-pyridine ( 7 ). Finally, attempts at cyclizing N-oxalyl-N′-(6-chloropyrid-2-yl)hydrazine derivatives ( 2g-2i ) with intentions of preparing various 3-acyl-5-chloro-s-triazolo[4,3-a]pyridines for entry into other 3,5-disubstituted systems were unsuccessful.     

A Convenient Synthesis of NovelDerivatives of Pyrido[2,3-d][1,2,4]triazolo[4,3-a]pyrimidine-5,6-dione

Summary.  Reaction of 6-Amino-2-thiouracil with hydrazonoyl halides yielded regioselectively 7-amino-1,3-disubstituted-1,2,4-triazolo[4,3-a]pyrimidine derivatives. Upon treatment with methyl (Z)-2-benzoylamino-3-dimethylaminopropenoate, the corresponding methyl (Z)-2-benzoylamino-3-([1,2, 4]triazolo[4,3-a]pyrimidin-7-yl)-amino propenoates were obtained which cyclized in the presence of sodium ethoxide to afford novel derivatives of pyrido[2,3-d][1,2,4]triazolo[4,3-a]pyrimidine-5,6-(1H,8H)-diones. E-mail: mosselhi@chem-sci.cairo.eun.eg Received February 8, 2002; accepted (revised) March 18, 2002     

On triazoles XXIII [1]. The reaction of 5-amino-1,2,4-triazoles with thiacyclohexane β-oxo esters [2]

Six novel isomeric ring systems, namely the thiopyrano[4,3-d]-1,2,4-triazolo[1,5-a]pyrimidine, the thiopyrano[3,4-e]-1,2,4-triazolo[1,5-a]pyrimidine, the thiopyrano[3,4-d]-1,2,4-triazolo[1,5-a]pyrimidine, the thiopyrano[4,3-e]-1,2,4-triazolo[1,5-a]pyrimidine, the thiopyrano[3,2-d]-1,2,4-triazolo[1,5-a]pyrimidine and the thiopyrano[2,3-e]-1,2,4-triazolo[1,5-a]pyrimidine were synthesised. Spectroscopical evidence was given for the structure of compounds obtained.     

Synthesis of 4(pyrazol-3-yl)[1,2,4]triazolo[4,3-a]quinoxalines and tetrazolo analog

The transformation of 2-chloro-3-[5-(acetoxymethyl)-1-phenylpyrazol-3-yl]quinoxaline 3 to 1-aryl-4-[5-(hydroxymethyl-1-phenylpyrazol-3-yl][1,2,4]triazolo[4,3-a]quinoxalines 4a-c has been achieved upon treatment with aroylhydrazines in boiling butanol. Compounds 4a-c were smoothly acetylated by acetic anhydride to give their acetyl derivatives 5a-c in good yield. 4-[5-(Acetoxymethyl)-1-phenylpyrazol-3-yl]-1-methyl[1,2,4]triazolo[4,3-a]quinoxaline was prepared by ring closure of 2-hydrazino-3-[5-(hydroxymethyl)-1-phenylpyrazol-3-yl]quinoxaline 6 by the action of acetic anhydride. The reaction of 6 with acetylacetone afforded 3-[5-(hydroxymethyl)-1-phenylpyrazol-3-yl]-2-(3,5-dimethylpyrazol-1-yl)quinoxaline 8 . In addition, the reaction of 3 with sodium azide in boiling N, N-dimethylformamide yielded the fused tetrazolo[1,5-a]quinoxaline 9 .     

Synthesis of tricyclic and tetracyclic thieno[3,2-f]-1,4-thiazepines

Treatment of 5-methylthio-2,3-dihydrothieno[3,2-f]-1,4-thiazepine ( 9 ) with acylhydrazines gave 5,6-dihydrothieno[3,2-f]-1,2,4-triazolo[4,3-d][1,4]thiazepines 10, 11 , and that of 9 with ethyl anthranilate gave 5,6-dihydrothieno[3′,2′:6,7][1,4]thiazepino[5,4-b]quinazolin-8-one ( 14 ). Reaction of 9 with hydrazine hydrate or 4-chlorophenylhydrazine afforded 5-hydrazino compounds 12, 15 , which were subsequently cyclized to ethyl 5,6-dihydrothieno[3,2-f]-1,2,4-triazolo[4,3-d][1,4]thiazepine-3-carboxylate ( 13 ), 2-(4-chlorophenyl)-5,6-dihydrothieno[3,2-f]-1,2,4-triazolo[4,3-d][1,4]thiazepin-3(2H)-one ( 16 ) and 2-(4-chlorophenyl)-6,7-dihydro-2H-thieno[3,2-f][1,2,4]triazino[4,3-d][1,4]thiazepine-3,4-dione ( 17 ). New thieno-anellated heterocycles were prepared with the aim of studying their affinity for the benzodiazepine receptors.