Synthesis of New Metal‐Free 1,4,8,11‐Tetraaza[14]annulene Derivatives Using 2‐Heteroaryl‐substituted Trimethinium Salts

The reaction of 2‐heteroaryl‐substituted trimethinium salts (A, B, and C) with aromatic 1,2‐diamines ( a , b , c , d , and e ) in acetonitrile/acetic acid leads to 6,13‐disubstituted 1,4,8,11‐tetraaza[14]annulene derivatives ( 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 ). The UV–vis spectral behavior of these compounds was examined in acetonitrile. Elemental analysis, IR, ¹H‐NMR, ¹³C‐NMR, and mass spectra confirm the molecular structure of the newly synthesized compounds.     

Synthesis of ω‐Substituted Alkanethiols and (Bromomethyl)methylthiomalonates

Several multifunctional derivatives of methylthiomalonic acid (=2‐(thiocarboxy)acetic acid), i.e. 20a , b , 21 , 22a, b , and 24 , were prepared from thiols bearing a functionalized head group, i.e. from 9a , b , 12 , and 16d , f (Schemes 4 and 5). The association constants of the two dithio podands 8b and 11 with K⁺ were determined.     

Synthesis of New Dibenzo-tetraaza and Dibenzo-dioxadiaza[14]annulene Derivatives Using 3-Bromo-substituted Vinamidinium Salt

Novel bromo-substituted derivatives of dibenzo-tetraaza and dibenzo-dioxadiaza[14]annulenes B–G were synthesized by a twofold condensation reaction of a symmetrical bromo-substituted vinamidinum salt A with ortho-diamino- and ortho-amino-hydroxyarenes such as 1,2-diaminobenzene, 1,2-diamino-4,5-dimethylbenzene, 2,3-diaminonaphthalene, 1,2-diamino-4-methylbenzene, 2-amino-1-hydroxybnzene, and 2-amino-1-hydroxy-5-methyl-benzene in acetonitrile/acetic acid as reaction medium. The ultraviolet/visible spectral behavior of these [14]annulenes was examined in dimethyl sulfoxide (DMSO). Elemental analysis, infrared, ¹H NMR, ¹³C NMR, and mass spectra confirm the molecular structure of the newly synthesized compounds.     

Synthesis and Structure of 2‐Substituted Thieno[3′,2′:5,6]pyrido[4,3‐d]pyrimidin‐4(3H)‐one Derivatives

A series of new 2‐substituted 3‐(4‐chlorophenyl)‐5,8,9‐trimethylthieno[3′,2′: 5,6]pyrido[4,3‐d]pyrimidin‐4(3H)‐ones 8 were synthesized via an aza‐Wittig reaction. Phosphoranylideneamino derivatives 6a or 6b reacted with 4‐chlorophenyl isocyanate to give carbodiimide derivatives 7a or 7b , respectively, which were further treated with amines or phenols to give compounds 8 in the presence of a catalytic amount of EtONa or K₂CO₃. The structure of 2‐(4‐chlorophenoxy)‐3‐(4‐chlorophenyl)‐5,8,9‐trimethylthieno[3′,2′: 5,6]pyrido[4,3‐d]pyrimidin‐4(3H)‐one ( 8j ) was comfirmed by X‐ray analysis.     

Synthesis of Furo[2,3‐d]pyridazin‐4(5H)‐one and Its N(5)‐Substituted Derivatives

We report the efficient preparation of furo[2,3‐d]pyridazin‐4(5H)‐one and its N‐substituted derivatives starting from methyl 2‐methylfuran‐3‐carboxylate. The Me group was converted to the aldehyde group, which was then condensed with hydrazine derivatives. Then, the ester functionalities were hydrolyzed to the corresponding acids, followed by treatment with SOCl₂ to give N‐substituted furopyridazinone derivatives.     

Synthesis of Some Novel 3‐Substituted Indole Derivatives Using Polyamine Functionalized Heterogeneous Catalyst

In present work, we have described the use of polyamine solid supported GN3 as catalyst in organic transformations using 1H‐indole‐3‐carbaldehyde. To the best of our knowledge, reports for the synthesis of chromen substituted at 3C position of indole are extremely rare in the literature. The polyamine functionalized immobilized silica (GN3) was found to be an excellent catalyst for synthesis of novel 2‐amino‐4‐(1H‐indol‐3‐yl)‐5‐oxo‐4,5‐dihydropyrano[3,2‐c]chromene‐3‐carbonitrile derivatives and Knoevenagel condensation. Catalyst GN3 was able to furnish excellent yield for a wide range of products. Moreover, the catalyst was reusable and reused for several times without loss of its catalytic activity.     

Synthesis of Novel Substituted 2‐Lactosylthiothieno[2,3‐d]pyrimidin‐4(3H)‐one Derivatives

The title compounds substituted 2‐lactosylthiothieno[2,3‐d]pyrimidin‐4‐ones 6 were synthesized by the glycosyl reaction and alcoholysis reaction of substituted 2‐thioxo‐thieno[2,3‐d]pyrimidin‐4‐ones 4 ,which is formed by the base catalytic and acetic acidify reaction of amino esters 2 with alkyl or arylisothiocyanates and hepta‐O‐acetyl‐lactosyl bromide in good yields. All of the compounds were confirmed by NMR, ESI‐MS, and elemental analysis.     

Synthesis and Cytotoxic Evaluation of Some 4‐Anilinofuro[2,3‐b]quinoline Derivatives

Some 4‐anilinofuro[2,3‐b]quinoline derivatives were synthesized from dictamnine, a natural alkaloid, and evaluated for their cytotoxicity in the NCI's full panel of 60 human cancer cell lines derived from nine cancer cell types, including leukemia, non‐small‐cell lung cancer, colon cancer, CNS cancer, melanoma, ovarian cancer, renal cancer, prostate cancer, and breast cancer. 1‐[4‐(Furo[2,3‐b]quinolin‐4‐ylamino)phenyl]ethanone ( 5 ) (mean GI₅₀=0.025 μM ), bearing an 4‐acetylanilino substituent at C(4) of furo[2,3‐b]quinoline, was more active than its 3‐acetylanilino counterpart 7 (mean GI₅₀=5.27 μM ), and both clinically used anticancer drugs, N‐[4‐(acridin‐9‐ylamino)‐3‐methoxyphenyl]methanesulfonamide (m‐AMSA; mean GI₅₀=0.44 μM ) and daunomycin (mean GI₅₀=0.044 μM ). Compound 5 was capable of inhibiting all types of cancer cells tested with a mean GI₅₀ of less than 0.04 μM in each case except for the non‐small‐cell lung cancer (average GI₅₀=1.75 μM ). Although non‐small‐cell lung cancer is resistant to compound 5 , the sensitivity within this type of cancer cells varies: HOP‐62 (GI₅₀<0.01 μM ), NCI‐H460 (GI₅₀=0.01 μM ), and NCI‐H522 (GI₅₀<0.01 μM ) are very sensitive, while HOP‐92 (GI₅₀ = 12.4 μM ) is resistant. Among these non‐small‐cell lung cancers, NCI‐H522 was found to be very sensitive to 5, 8a , and 8b with a GI₅₀ values of <0.01, 0.074, and <0.01 μM , respectively.     

Synthesis of 4-(4-Methylsulfonylphenyl)-3-phenyl-2(3H)-thiazole Thione Derivatives as New Potential COX-2 Inhibitors

Synthesis of novel 4-（4-methylsulfonylphenyl）-3-phenyl-2（3H）-thiazole thione derivatives with functionalized diarylheterocycle pharmacophore as potential COX-2 inhibitors was described. The title compounds were synthesized by cyclocondensation of corresponding dithiocarbamate and 2-bromo-1-（4-methylsulfonylphenyl）ethanone, followed by dehydration with H2SO4. All of the target compounds were characterized by ^1H NMR, IR and mass spectral data.     

Synthesis and Characterization of Nickel(II) and Copper(II) Complexes with Non-symmetric Tetraaza[14]annulene Derivatives. X-ray Crystal Structure of Copper(II) Complex

The complexes 13,14-([X]benzo)-3-(p-[Y]benzoyl)-2,4,9,11-tetramethyl-1,5,8,12-tetraazacyclotetradeca-l,3,9,11-tetraenato(2-)nickel(II), wherein Y = CH₃, H, Cl, NO₂ or OCH₃, X = CH₃ or Cl, have been synthesized and characterized. IR spectra of the benzoylated complexes show intense bands in the regions 1641-1654 cm^?1 attributable to the stretching modes of C—O. Hammett plots of the l/γ _max of π→π ^? have positive slopes of 0.251 for A series (X = CH₃) and 0.233 for B series (X = Cl), respectively, which are quite similar to those based on the NMR resonances of methine protons. The cyclic voltammograms of the complexes show two one-electron irreversible oxidation processes in the potential range of +0.1 to +0.8 V and two, three or four reduction peaks between ?1.2 and ?2.8 V depending on the substituents. Hammett plots of first and second oxidation potentials are linear with the positive slopes (0.039 and 0.057 V for A series, 0.036 and 0.047V for B series). The structure of the copper(II) complex (orthorhombic, C222₁, a= 8.0994(11), b= 8.3187(10), c= 24.561(5)Å, α(=β=γ)= 90.0°, Z= 4, R ₁= 0.0474 and wR ₂= 0.1219) was characterized using single crystal X-ray diffraction method.     

The Reaction of 3-Formylchromone with ortho-Substituted Anilines. Preparation of a Tetraaza [14]annulene

The reactions of 3-formylchromone ( 1 ) with 1, 2-phenylenediamine, 2-amino-diphenylamine and 2-aminophenol were reinvestigated and shown to yield 1, 8-dihydro-6, 13-di (2-hydroxybenzoyl)-dibenzo [b, i]-l, 4, 8, 11-tetraazacyclotetradeca- 4, 6, 11,13-tetraene ( 7 ), 3-[2-(1-phenyl)benzimidazolyl]chromone ( 10b ) and 3-(2-hydroxyphenyl)iminomethylchromone ( 4 ), respectively at variance with earlier reports. Compound 4 reacts with ethanol to give 2-ethoxy-3-[(2-hydroxyphenyl)-aminomethylidene]chroman-4-one ( 5b ). Dehydrogenation of 7 produces 3-(2-benz-imidazolyl)chromone ( 10a ), also at variance with earlier reports. The structures have been elucidated with the aid of NMR. and mass spectra. The reaction mechanism is discussed.     

Novel Synthesis of 3‐Amino‐4‐oxo‐(2H)‐pyrazolo[3′,4′:4,5]pyrimido‐[2,1‐b]benzothiazole and its 2‐ and 3‐Substituted Derivatives

Reaction of 4H‐pyrimido[2,1‐b]benzothiazole‐2‐thiomethyl‐3‐cyano‐4‐one (1) with hydrazine hydrate/aryl hydrazine/heteryl hydrazine in the presence of anhydrous potassium carbonate and dimethyl formamide afforded 3‐amino‐4‐oxo‐(2H)/aryl/heteryl pyrazolo[3′,4′:4,5]pyrimido[2,1‐b]benzothiazoles in good yield. These pyrazole derivatives on diazotization followed by replacement with hydroxy, chloro, bromo, iodo and on reduction gave the corresponding 3‐substituted derivatives.     

Synthesis and Antimicrobial Studies of New Bis[4,5‐dihydro‐1‐phenyl‐5‐thienyl‐3‐(phenyl‐4‐alkoxy)‐1H‐pyrazole] Derivatives

Syntheses and antimicrobial behavior of the alkyl linked new bispyrazolines 4a , 4b , 4c , 4d , 4e , 4f , 4g have been investigated. These compounds exhibited better antimicrobial activities as compared with their corresponding bischalcones. The structures of the prepared compounds ( 3a , 3b , 3c , 3d , 3e , 3f , 3g and 4a , 4b , 4c , 4d , 4e , 4f , 4g ) were determined from the rigorous analysis of their IR, ¹H NMR, ¹³C NMR, and mass spectral parameters.     

An Efficient Synthesis of Some Novel 3‐Cyano‐4‐imino‐2‐(methylthio)4H‐pyrido[1,2‐a]pyrimidine and Their Derivatives

Pyrazolo pyrimido pyrimidine ( 4a–k ) was prepared by the reaction of compound 3‐cyano‐4‐imino‐2‐(methylthio)4H‐pyrido[1,2‐a]pyrimidine ( 3 ) with hydrazine hydrate, phenyl hydrazine, 2‐hydrazino benzothiazole, and 6‐substituted hydrazine benzothiazole in N,N‐dimethylformamide and anhydrous potassium carbonate. These synthesized compounds were characterized by elemental analysis IR, ¹H NMR, and mass spectral data.     

Synthesis of 3‐phenyl‐5‐(trifluoromethyl)isoxazole and 5‐phenyl‐3‐(trifluoromethyl)isoxazole

Reaction of 4,4,4‐trifluoro‐1‐phenyl‐1,3‐butanedione with hydroxylamine led to the formation of 5‐hydroxy‐3‐phenyl‐5‐(trifluoromethyl)‐4,5‐dihydroisoxazole which was dehydrated to 3‐phenyl‐5‐(trifluoro‐methyl)isoxazole. This isomer can also be synthesized by reaction of 4‐chloro‐4‐phenyl‐1,1,1‐trifluoro‐3‐buten‐2‐one with sodium azide. The regioisomer, 5‐phenyl‐3‐(trifluoromethyl)isoxazole was synthesized by reaction of 1,1,1‐trifluoro‐4‐phenylbut‐3‐yn‐2‐one with hydroxylamine and by the reaction of 3‐chloro‐1‐phenyl‐4,4,4‐trifluorobut‐2‐en‐1‐one with sodium azide. Both isomers were characterized by mass and NMR spectroscopy.     

Synthesis of 3‐Substituted Benzpyrid‐4‐imino‐2‐oxime Derivatives

Pyrazolone, Isoxazolone, Pyrimidinone, Pyrimidinothione, thiazolidinone and β‐lactam incorporating 2‐oximino benzpyrid‐4‐one derivatives have been synthesized by cyclocondensation addition reaction and cycloaddition of hydrazine hydrate, phenyl hydrazine, hydroxylamine, urea, thiourea, mercapto acetic acid, and chloroacetylchloride, respectively.     

Synthesis and Characterization of Novel Arylaldehyde (Arylketone)‐(4‐Substituted phenyl‐5‐Substituted phenoxy‐Methyl‐4H‐1,2,4‐Triazole‐3‐yl)‐Thiol Acetyl Hydrazones

Fourteen novel arylaldehyde (arylketone)‐(4‐substituted phenyl‐5‐substituted phenoxy‐methyl‐4H‐1,2,4‐triazole‐3‐yl)‐thiol acetyl hydrazone derivatives ( 5a‐5g, 6a‐6g ) were synthesized by 4‐substituted phenyl‐5‐substituted phenoxy‐methyl‐1,2,4‐triazole‐3‐thione as starting material according to substructure link principle, followed by thioetherification, hydrazide hydrazone reaction. The structures of these compounds were confirmed by IR, ¹H NMR and elemental analysis. Crystal structure of compounds 1b and 6d were determined by the X‐ray diffraction.     

Synthesis of Derivatives of Pyrido[4,3‐d]pyrimidin‐4(3H)‐one via an Iminophosphorane

A series of new, 2‐substituted 3‐aryl‐8,9,10,11‐tetrahydro‐5‐methyl[1]benzothieno[3′,2′ : 5,6]pyrido[4,3‐d]pyrimidin‐4(3H)‐ones, compounds 5a – q , were designed and synthesized via the aza‐Wittig reaction as the key step. The iminophosphorane 1 reacted with phenyl isocyanate (or 4‐chlorophenyl isocyanate) to the carbodiimide 4 , which was cyclized to 5 upon addition of different amines, EtOH, or phenols in the presence of a catalytic amount of EtONa or K₂CO₃ (Schemes 1 and 2). The structures of compounds 5 were confirmed by IR, ¹H‐ and ¹³C‐NMR, EI‐MS, elemental analyses, and, in the case of 5l , by single‐crystal X‐ray diffraction (Figure).     

Synthesis of Certain 3-Aminopyrazolo[5,4-b]pyridine and 3,4-Substituted Pyrido[2′,3′：3,4]pyrazolo[5,1-c][1,2,4]triazine Derivatives

2-Thioxo-1,2-dihydropyridine derivatives 2a, 2b were reacted with methyl iodide to give 2-methylthiopyridines 3a, 3b, which were reacted with hydrazine hydrate to produce 3-aminopyrazolo[5,4-b]pyridines 4a, 4b. Compounds 4a, 4b were diazotized to afford the corresponding diazonium salts 5a, 5b, which were reacted with some active methylene compounds 6a-6h to give the corresponding pyrido[2′,3′ ： 3,4]pyrazole[5,1-c][1,2,4]triazines 7-14.