Synthesis of Some New Heterocycles Derived from Phenylacetyl Isothiocyanate

Phenylacetyl isothiocyanate (1) was reacted with benzoyl hydrazine (2a) in acetonitrile to give thiosemicarbazide derivative 3 which was cyclized by polyphosphoric acid to give 1,2,4-triazoline-5-thione derivative 4. Treatment of 1 with thiosemicarbazide (2b) yielded another 1,2,4-triazoline-5-thione derivative 5. Similar treatment of 1 with phenyl hydrazine (2c) in acetonitrile gave a differently substituted 1,2,4-triazoline-5-thione derivative 6 in one pot-reaction. On the other hand, when the reaction was carried out in acetone, a mixture of 6 and thiadiazolidine derivative 7 was obtained. However, reaction of 1 with hydrazine hydrate (2d) gave hydrazine derivative 8. Reaction of isothiocyanate 1 with anthranilic acid (9) gave benzo[d][1,3,6]oxazin-1-one derivative 10. Treatment of 1 with 2-aminothiophenol (11a), 2-aminophenol (11b) or o-phenylenediamine (11c) produced benzothiazole derivative 12a, benzoxazole derivative 12b and benzimidazole derivative 12c, respectively. The structures of all the products were confirmed by micro-analytical and spectral data.     

Studies on imidazole derivatives and related compounds. 4. Synthesis of O-glycosides of 4-carbamoylimidazolium-5-olate

Ribosylation of trimethylsilyl derivative of 1-(4-nitrobenzyl)-5-carbamoylimidazolium-4-olate ( 5 ) with 1,2,3,5-tetra-O-acetyl-β- D -ribofuranose in the presence of stannic chloride and trimethylsilyl trifluoromethanesulfonate afforded no 5-O-glycosides but N-1 ribosylated compound ( 6 ). However, 5-O-riboside ( 7a ) and its orthoamide derivative ( 8 ) were given by glycosylation of tri-n-butylstannyl derivative of 5 with 2,3,5-tri-O-acetyl-β- D -ribofuranosyl chloride in the presence of silver trifluoromethanesulfonate. This procedure was successfully applied to other sugars and 5-O-glucuronide ( 11 ), a possible metabolite of 1 in vivo, was obtained as one of the 5-O-glycoside derivatives.     

Synthesis of 1,2:5,6-Di-O-isopropylidene-3-O-[3-(5-fluorouracil-1-yl)-propionoyi]-α-D-glucofuranose and its antitumor activity

In order to provide a less toxic 5-fluorouracil derivative, 1,2:5,6-di-O-isopropylidene-3-O-[3-(5-fluorouracill-yl)-propionoyl]-α-D-glucofuranose, which was the derivative of 5-fluorouracil combining indirectly to 3-position of diacetoneglucose, was synthesized, and its antitumor activity was tested.     

Synthesis, Reactions, and Anti-arrhythmic activity of Substituted Heterocyclic Systems Using 5-Chloroanisic Acid as Starting Material

Summary. A series of substituted heterocyclic systems were prepared from N1-[4-(4-fluorocinnamoyl)phenyl]-5-chloro-2-methoxybenzamide, which was prepared from the corresponding 5-chloroanisic acid (2-methoxy-4-chlorobenzoic acid) as starting material. Treating of the cinnamoyl derivative with hydrazine hydrate in dioxane afforded a pyrazoline, which was reacted with morpholine and paraformaldehyde to give the N-substituted pyrazoline. Acylation of pyrazoline with acetyl chloride in dioxane afforded the N-acetyl analogue. Also, the cinamoyl derivative was reacted with methylhydrazine, phenylhydrazine, or ethyl cyanoacetate to yield the corresponding N-methyl-, N-phenylpyrazoline, pyrane, and pyridone derivatives. Condensation of the cinnamoyl derivative with cyanothioacetamide gave the pyridinethione derivative, which was treated with ethyl chloroacetate affording the ethyl carboxylate derivative. Also, it was reacted with malononitrile or ethyl acetoacetae to give the cyano amino analougues and ethyl carboxylate, which was reacted with methylhydrazine to give the (indazolyl)phenyl derivative. On the other hand, reaction of cinnamoyl derivative with acetyl acetone afforded the cyclohexenyl derivative, which was reacted with hydrazine hydrate to give the [methylindazolyl]phenyl derivative. Condensation of the cinnamoyl derivative with guanidine hydrochloride or thiourea afforded the aminopyrimidine derivative and thioxopyrimidine. The latter was condensed with chloroacetic acid to yield a thiazolopyrimidine, which was condensed with 2-thiophenealdehyde to yield the arylmethylene derivative, however, it was also prepared directly from thiopyrimidine by the action of chloroacetic acid, 2-thiophenealdehyde, and anhydrous sodium acetate. The pharmacological screening showed that many of these compounds have good anti-arrhythmic activity and low toxicity.     

Chemical conversion of uridine to 8,5′-O-cyclo-3-deazaguanosine

Treatment of 1-(2,3-O-isopropy lidene-β-D-ribofuranosyl)-2-oxo-4-imidazoline-4-carboxylic acid methyl ester with formaldehyde gave the 5-hydroxymethyl derivative which, after aeetylalion, gave the 5-eyanomelhyl derivative by treatment with tetra-n-butylammonium cyanide. The 2,5′-O-cyclo derivative of the 5-cyanomethylimidazole-4-carboxylate was converted to the title compound by treatment with ammonia. The present sequence of reactions furnished the chemical conversion of uridine to a 3-deazaguanosine via the imidazole nucleoside as the intermediate.     

Synthesis of [1,5-A]Pyrimidinone Ring Derivatives

Cyclodehydrogenation of the benzalhydrazino derivatives 5 and 6 gave 6-cyano-7-(4-methoxyphenyl)- 2-phenyl-5-oxo-1,2,4-triazolo[1,5-a]pyrimidine (8) and 6-cyano-7-(4-methoxyphenyl)-4-methyl-2-phenyl- 5-oxo-1,2,4-triazolo[1,5-a]pyrimidine (9) respectively. Melhylation, acetylation and benzylation of 8 gave the corresponding N-methyl, acetyl and benzyl derivatives 10-12 . Methylation of 5 with dimethylsulfate gave 2-benzalhydrazino-5-cyano-3-methyl-6-(4-methoxyphenyl)-3,4-dihydropyrimidin-4-one (6) , of which the reaction with acetic anhydride in pyridine afforded the N-acetylbenzalhydrazino derivative 15 . The latter was also prepared from acetylation of 5 followed by medthylation with iodomethane. Acetylation of 5 with boiling acetic anhydride afforded the diacetyl derivative 16 , whereas its benzylation gave the mono-N-benzyl derivative 14 .     

Directed regiospecificity of 1,3-dipolar cycloaddition of 2-diazopropane to 4- and 5-substituted pyridazin-3(2H)-ones

6-Methoxy-2-methylpyridazin-3(2H)-one ( 1 ) gave with 2-diazopropane ( 8 ) a mixture of 3H-pyrazolo[3,4-d]-pyridazin-4(5H)-one derivative 12 , as the main product, and -7(6H)-one derivative 10 , as the minor product. On the other hand, 4-substituted pyridazin-3(2H)-ones 2, 3 , and 4 gave 3H-pyrazolo[3,4-d]pyridazin-7(6H)-one 10 , exclusively, while 5-substituted pyridazin-3(2H)-ones 5, 6 , and 7 produced only the isomeric 3H-pyrazolo[3,4-H]pyridazin-4(5H)-one 12 . The 5-phenylsulfonyl derivative 13 gave with 8 by elimination of a molecule of nitrogen, followed by rearrangement, 1,2-diazepine derivative 15 and with an excess of 8 3H-pyrazolo[3,4-d][1,2]diazepine derivative 16. 1 ,2-Dimethylpyridazine-3,6-(1H,2H)-dione and its derivatives 18 and 19 produced 3H-pyrazolo[3,4-d]pyridazine-4,7(5H,6H)-dione derivative 23 , while from 17 and 1-diazoindane ( 24 ) the spiro compound 27 was obtained. The 1,2-dihydro and 3a,7a-dihydro intermediates 21 and 25 were isolated.     

On triazoles. XXV. The reaction of methyl (5-amino-3-Q-1H-1,2,4-triazolyl)dithiocarbonates with amines

Different “functionalised” triazolylthioamides 3 and -thioureas 4 were synthesised. The ring closure of the ω-hydroxyalkylthioamides 3/2–5 led to the corresponding 2-thiazoline 5/2–4 and 5,6-dihydro-4H-1,3-thiazine 5/5 derivatives, respectively. Unexpectedly, the ring closure of the corresponding 2,2-dimethoxyethyl derivative 3/18 led depending on the reaction conditions to a thiazole derivative 6 or to its 1,2,4-triazolo[3,4-b]-1,3,5-triazepin-5(9H)-thione isomer 7 representing a novel ring system. To corroborate its structure 7 was methylated to the corresponding S-methyl derivative 8 . Spectroscopical evidence is given for the structure of derivatives 3–8 obtained.     

Synthesis of some new pyrazoloquinazolinone and quinazolinone derivatives

The benzoxazinone derivative 2‐(6,8‐dibromo‐4‐oxo‐4H‐benzo[d]‐1,3‐oxazin‐2‐yl)‐3‐(4‐methoxyphenyl) acrylonitrile ( 1 ) has been used as a starting material for preparation of the hitherto unknown pyrazoloquinazolinone and quinazolinone derivatives. Under different conditions the benzoxazinone ( 1 ) was reacted with hydrazine hydrate to provide the pyrazolocarbonitrile derivative ( 2 ) and the azine derivative ( 3 ) and/or the pyrazoloquinazoline derivative ( 4 ). When ( 4 ) was conducted to react either with EAA (ethyl acetoacetate) or Ac₂O/AcOH (acetic anhydride/acetic acid) mixture or phthalic anhydride/acetic acid mixture, the pyrazoloquinazoline carbonitrile ( 5 ), pyrazolo‐quinazoline acetic acid ( 6 ) or the pyrazoloquinazolinone derivative ( 7 ) were formed respectively. When ( 1 ) was reacted with phenylhydrazine, a mixture of the quinazolinone derivative ( 8 ) and the hydrazone derivative ( 9 ) were obtained. The benzoxazinone derivative ( 1 ) was found also to react with benzylamine in ethanol or without solvent to give the quinazolinone derivative ( 10 ) or the quinazolindione ( 11 ) respectively. Fusion of ( 1 ) with ammonium acetate yielded the quinazolinone ( 12 ), which was methylated to give ( 13 ) and thiated to the thioxyquinazoline derivative ( 14 ), while reaction of ( 1 ) with formamide gave the N‐formylquinazoline derivative ( 15 ).     

Synthesis and Reactions of Some Substituted Heterocyclic Systems as Anti-arrhythmic Agents

A series of substituted heterocyclic systems were prepared from N ¹-[4-(2-thienylmethylene)phenyl]-5-chloro-2-methoxybenzamide, which was prepared from the corresponding 5-chloroanisic acid (2-methoxy-4-chlorobenzoic acid) as starting material. Condensation of the thienylmethylene derivative with guanidine hydrochloride, urea, or thiourea afforded the aminopyrimidine, pyrimidinone, and thioxopyrimidine derivatives. The latter was condensed with chloroacetic acid to yield a thiazolopyrimidine, which was condensed with 2-thiophenealdehyde to yield the arylmethylene derivative, however, it was also prepared directly from thiopyrimidine by the action of chloroacetic acid, 2-thiophenealdehyde, and anhydrous sodium acetate. Treating of the thienylmethylene derivative with phenylhydrazine or hydrazine hydrate in dioxane afforded N-phenylpyrazoline and a pyrazoline, which was reacted with acetyl chloride in dioxane affording the N-acetyl analogue. The thienylmethylene derivative was reacted with malononitrile or ethyl cyanoacetate in the presence of ammonium acetate to yield the corresponding cyanoaminopyridine and cyanopyrimidone derivatives. Also, it was reacted with hydroxylamine hydrochloride in pyridine to give the oxime derivative, which was cyclized with acetic anhydride. On the other hand, condensation of the thienylmethylene derivative with ethyl cyanoacetate in the presence of sodium ethoxide or cyanothioacetamide gave the cyanopyrane and pyridine thione derivative, which was treated with ethyl chloroacetate affording the ethyl carboxylate derivative. The pharmacological screening showed that many of these compounds have good anti-arrhythmic activity and low toxicity.     

Synthesis and Reactions of Some Substituted Heterocyclic Systems as Anti-arrhythmic Agents

Summary. A series of substituted heterocyclic systems were prepared from N ¹-[4-(2-thienylmethylene)phenyl]-5-chloro-2-methoxybenzamide, which was prepared from the corresponding 5-chloroanisic acid (2-methoxy-4-chlorobenzoic acid) as starting material. Condensation of the thienylmethylene derivative with guanidine hydrochloride, urea, or thiourea afforded the aminopyrimidine, pyrimidinone, and thioxopyrimidine derivatives. The latter was condensed with chloroacetic acid to yield a thiazolopyrimidine, which was condensed with 2-thiophenealdehyde to yield the arylmethylene derivative, however, it was also prepared directly from thiopyrimidine by the action of chloroacetic acid, 2-thiophenealdehyde, and anhydrous sodium acetate. Treating of the thienylmethylene derivative with phenylhydrazine or hydrazine hydrate in dioxane afforded N-phenylpyrazoline and a pyrazoline, which was reacted with acetyl chloride in dioxane affording the N-acetyl analogue. The thienylmethylene derivative was reacted with malononitrile or ethyl cyanoacetate in the presence of ammonium acetate to yield the corresponding cyanoaminopyridine and cyanopyrimidone derivatives. Also, it was reacted with hydroxylamine hydrochloride in pyridine to give the oxime derivative, which was cyclized with acetic anhydride. On the other hand, condensation of the thienylmethylene derivative with ethyl cyanoacetate in the presence of sodium ethoxide or cyanothioacetamide gave the cyanopyrane and pyridine thione derivative, which was treated with ethyl chloroacetate affording the ethyl carboxylate derivative. The pharmacological screening showed that many of these compounds have good anti-arrhythmic activity and low toxicity.     

Synthesis and characterization of some nitrogen heterocycles from d-galactose derivatives

The tetrazoles 5-(6′-acetamido-6′-deoxy-1′,2′:3′,4′-di-O-isopropylidene-D-glycero-α-D-galactohexopyranos-6′-yl)tetrazole ( 1 ) and 5-(6′-acetamido-6′-deoxy-1′,2′:3′,4′–di-O-isopropylidene-L-glycero-α-D-galacto-hexopyranos-6′-yl)-tetrazole ( 2 ) were synthesized by the 1,3-dipolar cycloaddition reaction of the epimeric α-acetamidonitriles 5 and 6 , respectively, with sodium azide. Reaction of tetrazole 1 with acetic anhydride in the presence of pyridine afforded the N-acetyl-1,3,4-oxadiazole derivative 3 and the N-acetylacetamido-1,3,4-oxadiazole derivative 7 . The N-acetylacetamido-1,3,4-oxadiazole derivative ( 8 ) was isolated when the tetrazole 2 was allowed to react under the same conditions. The physical and spectroscopic data of the five new compounds 1, 2, 3, 7 and 8 are presented.     

Application of photoelectron spectroscopy to biologically active molecules and their constituent parts. II. 1,4-Benzodiazepines

The Hel photoelectron (PE) spectra of 5-phenyl-7-chloro-2H-1,4-benzodiazepin-2-one ( 1 ), its 1-methyl derivative ( 2 ), 3-hydroxy derivative ( 3 ), 1-methyl-3-hydroxy derivative ( 4 ), 3-(S)-methyl derivative ( 5 ), and 1-methyl-3-(S)-methyl derivative ( 6 ) have been recorded. The electronic structure of these compounds is discussed on the basis of the observed ionization energies, and of the semiempirical CNDO/2 calculations on model compounds 1a-6a , which have a hydrogen instead of the phenyl group in the 5-position. As a result the character of the seven highest occupied orbitals in 1–6 have been assigned.     

Imidazo[1,2-α]pyridine anthelmintics. Synthesis of 6-phenylaminoimidazo[1,2-α]pyridine-2-carbamate and 5-acylaminopyridines by a chapman rearrangement

The title compound, a potential anthelmintic agent, was prepared in seven steps from 5-hydroxy-2-picoline. The intermediate 5-(N,-phenylbenzamido)-2-picoline was prepared by a facile Chapman rearrangement of the corresponding benzimidoyl ester. Oxidation and Curtius rearrangement of the substituted picoline gave 5-(N-phenylbenzamido)-2-aminopyridine which underwent ring closure and debenzoylation to furnish methyl 6-phenylaminoimidazo[1,2-α]pyridine-2-carbamate. Fries rearrangement of the penultimate N-benzoyl derivative gave a 6-(p-benzoylphenylamino)imidazo[1,2-α]pyridine derivative, whose structure was confirmed by cmr study. The title compound lacked significant anthelmintic activity.     

Potential psychotropic agents. 7-Chloro-9-phenyl-3,3-diethyl-3H-pyrazolo-[5, 1-b]quinazolin-10-ium-2-olate and 9-Chloro-2,3,4,5-tetrahydro-1-methyl-3,3-diethyl-7-phenyl-1H-benzo-1,5,6-triazonine-2,4-dione

2-Amino-5-chloro-α-phenylbenzylidene hydrazone ( 1 ) or its methyl derivative 2 or acetyl derivative 10 react with diethylmalonic esters to give the corresponding malonyl derivatives 3, 4 and 8 . These esters were hydrolyzed to the acids 5 and 6 . Treating 5 with dehydrating agents the mesoionic compound 7-chloro-9-phenyl-3,3-diethyl-3H-pyrazolo[5,1-b]quinazolin-10-ium-2-olate (14) was obtained, while the methyl derivative 6 afforded the desired 9-chloro-2,3,4,5-tetrahydro-1-methyl-3,3-diethyl-7-phenyl-1H-benzo-1,5,6-triazonine-2,4-dione ( 17 ). Some derivatives of these compounds were also described. The structures of the new compounds were confirmed by an alternative synthesis and by mass and prnr spectral data.     

Studies on imidazole derivatives and related compounds. I. Synthesis of novel antineoplastic derivatives of 4-carbamoylimidazolium-5-olate

Acylation of 4-carbamoylimidazolium-5-olate ( 2 ) with a variety of acid chlorides produced 4(5)-carbamoyl-1H-imidazol-5-(4)yl acid carboxylates ( 3a-j ). Treatment of esters 3a,c with sodium hydroxide gave imides, 4a,c . Methylation of 3a and 2 with diazomethane gave the N-3 methyl derivative ( 6 ) and a mixture of the N-3, O-dimethyl derivative ( 9 ), the N-1, N-3-dimethyl derivative ( 10 ) and the O-methyl derivative ( 11 ), respectively. 5-Carbamoyl-1-methylimidazolium-4-olate ( 7 ) and its 4-carbamoyl isomer ( 16 ) were prepared from 2-aminopropanediamides 8 and 15 , respectively. Treatment of the imidazolium compound ( 10 ) with aqueous potassium hydroxide gave the recyclized product, 1-methyl-5-methylcarbamoylimidazolium 4-olate ( 18 ). Methyl derivatives 6, 7 , and 9 except 16 demonstrated the complete lack of antitumor activity against Lewis lung carcinoma or sarcoma 180 in mice.     

The Synthesis of Bicyclic N4-Amino-2′-deoxycytidine Derivatives

Nucleosides which have ambivalent tautomeric properties have value in a variety of nucleic acid hybridization applications, and as mutagenic agents. We describe here synthetic studies directed to stable derivatives of this kind of nucleoside based on N⁴-aminocytosine. Treatment of the 4-(1H-1,2,4-triazol-1-yl)-5-(chloroethyl)pyrimidinone nucleoside derivative 5 with hydrazine leads to formation of the 6,6-bicyclic pyrimido-pyridazin-7-one 3 , and with methylhydrazine to the corresponding fixed tautomeric 1-methyl derivative 7 (Scheme 1). If these cyclization reactions are carried out in the presence of a base, the 6-ring bicyclic derivatives undergo rearrangement to their corresponding 5-ring pyrrolo-pyrimidin-2-one analogues 8 (Scheme 2). In the reaction of the triazolyl derivative 5 with 1-[(benzyloxy)carbonyl]-1-methylhydrazine, spontaneous cyclization gives the 5-ring derivative 13 related to 8 rather than the open-chain product 12 (Scheme 4). Reaction of an acetylated analogue of triazolyl derivative 5 with 1,1-dimethylhydrazine gives rise to some of the open-chain product 9 , but it too cyclizes to a product that we have assigned the structure of the 6,6-ring quaternary ammonium salt 11 (Scheme 3).     

The Donor-Acceptor-Acceptor Purine Analog: Transformation of 5-aza-7-deaza-1H-isoguanine (=4-aminoimidazo-[1,2-a]-1,3,5-triazin-2(1H)-one) to 2′-deoxy-5-aza-7-deaza-isoguanosine using purine nucleoside phosphorylase

A new synthesis is reported for 4-aminoimidazo[1,2-a]-1,3,5-triazin-2(1H)-one ( =5-aza-7-deaza-isoguanosine; 8 ), a purine analog that, when incorporated into an oligonucleotide chain, presents a H-bond donor-acceptor-acceptor pattern to a complementary pyrimidine analog. A protected ribose derivative was coupled to 8 to yield 4-amino-8-(β-D -ribofuranosyl)imidazo[1,2-a]-1,3,5-triazin-2(8H)-one ( =5-aza-7-deaza-isoguanosine; 11 ) after deprotection, Alternatively, direct synthesis of both the ribo derivative 11 and the corresponding deoxyribo derivative 17 as the β-D -anomers was achieved using the enzyme purine nucleoside phosphorylase in a one-pot reaction. This adapts a known synthetic approach to yield a new strategy for obtaining diastereoisomerically pure deoxyribonucleoside analogs on 1-gram scales.     

Studies on the syntheses of azole derivatives. Part VII. Syntheses of 1 -phenyl-Δ2-1,2,4-triazolin-5-one derivatives [studies on the syntheses of heteroeyclic compounds. CD XI]

Bromination of 3-methyl-1-phenyl-Δ²-1,2,3-lriazolin-5-one (II) and its 4-phenyl derivative III afforded the corresponding I-(p-Bromophenyl) derivatives IV and V, respectively. (Chlorination of the 4-phenyl derivative III gave I-(P-chlorophenyl) derivative VI. In addition, 3-N-subsuituted-carhamoyl-1,2,4-triazolin-5-ones(XII, XIII, and XIV) were synthesized by the Schotten-Baumann reaction of 3-carboxy-1-phenyl-Δ²-1,2,4-triazolin-5-one (XI) with various amines.     

Furopyridines. V. A simple synthesis of furo[2,3-c]pyridine and its 2-and 3-methyl derivatives

A simple synthesis of furo[2,3-c]pyridine and its 2- and 3-methyl derivatives from ethyl 3-hydroxyisonicotinate ( 2 ) is described. The hydroxy ester 2 was O-alkylated with ethyl bromoacetate or ethyl 2-bromopropionate to give the diester 3a or 3b . Cyclization of compound 3a afforded ethyl 3-hydroxyfuro [2,3-c]pyridine-2-carboxylate ( 4 ) which was hydrolyzed and decarboxylated to give furo[2,3-c]pyridin-3(2H)-one ( 5a ). Cyclization of 3b gave the 2-methyl derivative 5b . Reduction of 5a and 5b with sodium borohydride yielded the corresponding hydroxy derivative 6a and 6b , respectively, which were dehydrated with phosphoric acid to give furo[2,3-c]pyridine ( 7a ) and its 2-methyl derivative 7b . 4-Acetylpyridin-3-ol ( 8 ) was O-alkylated with ethyl bromoacetate to give ethyl 2-(4-acetyl-3-pyridyloxy) acetate ( 9 ). Saponification of compound 9 , and the subsequent intramolecular Perkin reaction gave 3-methylfuro[2,3-c]pyridine ( 10 ). Cyclization of 9 with sodium ethoxide gave 3-methylfuro[2,3-c]pyridine-2-carboxylic acid, which in turn was decarboxylated to give compound 10 .