Synthesis of N-aryl hydrazides by copper-catalyzed coupling of hydrazides with aryl iodides

[reaction--see text] A convenient method for intermolecular N-arylation of hydrazides with substituted aryl iodides in the presence of a copper catalyst and Cs(2)CO(3) is reported. The C-N coupling of N-Boc hydrazine with para- and meta-substituted aryl iodides afforded the N-arylated products A, regioselectively. A reversal in regioselectivity is observed for the arylation of benzoic hydrazide with ortho-substituted aryl iodides, providing the N'-arylated products B.

Hydrogen Bonded Oligohydrazide Foldamers and Their Recognition for Saccharides

This paper describes the synthesis and characterization of the first series of hydrogen bonding-driven hydrazide foldamers and their recognition for alkyl saccharides in chloroform. Oligomers 1, 2-4, 5, 6, and 7, which contain one, two, four, six, or twelve repeated dibenzoyl hydrazide residues, respectively, have been prepared. The rigid and planar conformations of 1 and 2 or 4 have been established with X-ray analysis and (1)H NMR spectroscopy, whereas the folding and helical conformations of 5-7 have been evidenced by the 1D and 2D (1)H NMR and IR spectroscopy and molecular mechanics calculations. Molecular mechanics calculations also revealed that 5, 6, and 7 possess a rigid cavity with size of ca. 10.6 to 11.1 A, and half of the carbonyl groups in the folding conformations are orientated inwardly inside the cavity. (1)H NMR and CD experiments revealed that 5-7 efficiently complex alkylated mono- and disaccharides 32-35 in chloroform. The association constants (K(assoc)) of the complexes have been determined with the (1)H NMR and fluorescent titration methods. The energy-minimized conformation of 6.34 has been obtained with molecular mechanics calculation. The hydrazide-based folding structures described here represent novel examples of hydrogen bonding-driven foldamers that act as artificial receptors for selective molecular recognition.

Polysubstituted pyrazoles, part 5.11For part 4: see Ref. [18]. Synthesis of new 1-(4-chlorophenyl)-4-hydroxy-1H-pyrazole-3-carboxylic acid hydrazide analogs and some derived ring systems. A novel class of potential antitumor and anti-HCV agents

A novel series of 1-(4-chlorophenyl)-4-hydroxy-1H-pyrazole-3-carboxylic acid hydrazide analogs and some derived 4-substituted-1,2,4-triazolin-3-thiones, 2-substituted-1,3,4-thiadiazole and 2-substituted-1,3,4-oxadiazoles has been synthesized. Ten of the newly synthesized compounds were selected by the National Cancer Institute (NCI)-in vitro-disease oriented antitumor screening to be evaluated for their antitumor activity. Seven compounds, namely 7a-c, 9, 11, 13 and 14, exhibited potential and broad spectrum antitumor activity against most of the tested subpanel tumour cell lines (GI50<100 microM). Compounds 14 (GI50, TGI, and LC50 MG-MID values of 0.08, 15.8 and 64.6 microM, respectively) and 11 (GI50, TGI, and LC50 MG-MID values of 0.20, 11.7 and 87.1 microM, respectively) proved to be the most active members in this study with potential activity against all the tested subpanel tumour cell lines and particular effectiveness on the leukaemia subpanel at both the GI50 (0.03 and 0.09 microM, respectively) and the TGI levels (35.2 and 28.1 microM, respectively). Moreover, compound 14 exhibited a super sensitivity profile towards about 26 different cancer cell lines with GI50 values lying in the nanomolar concentration range (GI50 values<0.01 microM). In addition, compounds 2-5, 6a-d, 7a, 8-11, 12a, 13, 14 were investigated for their in vitro effect on the replication of hepatitis-C virus (HCV) in HepG2 hepatocellular carcinoma cell line infected with the virus using the reverse transcription-polymerase chain reaction (RT-PCR) technique. The results revealed that compounds 2 and 5 were capable of inhibiting the replication of both the HCV RNA (+) and (-) strands at 10-100 microg mL(-1) concentration range.

Synthesis and structure–activity relationships of novel 1-arylmethyl-3-aryl-1H-pyrazole-5-carbohydrazide derivatives as potential agents against A549 lung cancer cells

A series of novel 1-arylmethyl-3-aryl-1H-pyrazole-5-carbohydrazide derivatives were synthesized, and the effects of all the compounds on A549 cell growth were investigated. The results showed that all the nine compounds had inhibitory effects on the growth of A549 cells and induced the cell apoptosis. The study on structure-activity relationships and prediction of lipophilicities of compounds showed that compounds with logP values in the range of 3.12-4.94 had more inhibitory effects on the growth of A549 cells.

Unsymmetrically substituted benzonaphthoporphyrazines: a new class of cationic photosensitizers for the photodynamic therapy of cancer

Unsymmetrical zinc(II) complexes of benzonaphthoporphyrazines 5a-12a bearing between one and eight pyridyloxy substituents are synthesized by statistical tetramerization of 6-(1,1-dimethylethyl)-2,3-naphthalenedicarbonitrile (1) with 4-(3-pyridyloxy)- or 4,5-bis-(3-pyridyloxy)-1,2-benzenedicarbonitrile (2, 3). Methylation of 5a-12a leads to the catianic pyridyloxybenzonaphthoporphyrazines 5b-12b having between one to eight positive charges. The Q-band transition in the visible spectra exhibits a bathochromic shift from 680 to 760 nm dependent upon the number of annelated naphthalene rings. The singlet oxygen quantum yields of the benzonaphthoporphyrazines determined by the dye-sensitized photooxidation of 1,3-diphenylisobenzofurane is surprisingly high (in the range of zinc phthalocyanine). The photooxidative stabilities of the photosensitizers described quantitatively by first-order kinetics decrease with the number of annelated naphtho groups. A linear correlation between the logarithm of the decomposition rate constant and the position of the highest occupied molecular orbital (HOMO)-level of the photosensitizers is found. Destabilization of the HOMO leads to a decrease of the photostability. Due to their adjustable long wavelength absorption, their intramolecular polarity axis and their different hydrophilic/hydrophobic character, these novel compounds may be suitable photosensitizers for the photodynamic therapy of cancer.

Synthesis of novel substituted pyrazole-5-carbohydrazide hydrazone derivatives and discovery of a potent apoptosis inducer in A549 lung cancer cells

A series of novel 3-aryl-1-(4-tert-butylbenzyl)-1H-pyrazole-5-carbohydrazide hydrazone derivatives were synthesized and the effects of all the compounds on A549 cell growth were investigated. The results showed that all compounds had inhibitory effects on the growth of A549 lung cancer cells and compound (E)-1-(4-tert-butylbenzyl)-N'-(1-(5-chloro-2-hydroxyphenyl) ethylidene)-3-(4-chlorophenyl)-1H-pyrazole-5-carbohydrazide (3e) possessed the highest growth inhibitory effect and induced apoptosis of A549 lung cancer cells.

Copper-Catalyzed Vinylation of Hydrazides. A Regioselective Entry to Highly Substituted Pyrroles

A modular route to highly substituted pyrroles has been developed. This transformation consists of two sequential copper-catalyzed vinylations of bis-Boc-hydrazine followed by thermal rearrangement/cyclization. A wide variety of functionalized pyrroles can be prepared in a selective manner from simple and easily accessible precursors. [reaction: see text]

Synthesis, antimicrobial activity and conformational analysis of novel substituted pyridines: BF3-promoted reaction of hydrazine with 2-alkoxy pyridines

Some new 2-alkoxy-3-cyano-4,6-diarylpyridines 3,4 were synthesized by condensation of different alpha,beta-unsaturated ketones 1 with malononitrile 2, followed by cyclization in sodium alkoxide/alcohol system. Lewis acid-catalyzed reaction of 4 with hydrazine afforded the corresponding 1H-pyrazolo[3,4-b]pyridines 5. The potency of the results as antimicrobial agents has been evaluated. The structure of the newly prepared compounds was assessed by microanalysis, IR and NMR spectra. Molecular mechanics (MM2) and semiemperical (AM1) molecular orbital calculations have been performed for the most biologically active compounds 5b and c to get insight into their molecular structures and to learn more about their stable molecular conformations.

Substituted 1,3,4-thiadiazoles with anticonvulsant activity. 1. Hydrazines

The synthesis and anticonvulsant activity of a series of 2-aryl-5-hydrazino-1,3,4-thiadiazoles are described. The combination of preferred aromatic substituents in the 2-position coupled with alkyl substitution on the hydrazine moiety led to a number of potent compounds lacking sedation, ataxia, or lethality. 5-(2-Biphenylyl)-2-(1-methylhydrazino)-1,3,4-thiadiazole (4m) represents a new class of anticonvulsant agent and compares favorably with the standard drugs phenytoin, phenobarbital, and carbamazepine.

New and versatile ternary ligand system for technetium radiopharmaceuticals: water soluble phosphines and tricine as coligands in labeling a hydrazinonicotinamide-modified cyclic glycoprotein IIb/IIIa receptor antagonist with 99mTc

A hydrazinonicotinamide-functionalized cyclic platelet glycoprotein IIb/IIIa (GPIIb/IIIa) receptor antagonist [cyclo(D-Val-NMeArg-Gly-Asp-Mamb(5-(6-(6-hydrazinonicotin amido) hexanamide))) (HYNIC-tide)] was labeled with 99mTc using tricine and a water soluble phosphine (TPPTS, trisodium triphenylphosphine-3,3',3"-trisulfonate; TPPDS, disodium triphenylphosphine-3,3'-disulfonate; or TPPMS, sodium triphenylphosphine-3-monosulfonate] as coligands. The synthesis of technetium complexes, [99mTc(HYNICtide)(L)(tricine)] (1, L = TPPTS; 2, L = TPPDS; 3, L = TPPMS), can be performed in one or two steps in high yield and with high specific activity (> or = 20,000 Ci/mmol). For example, the reaction of the HYNICtide, [99mTc]pertechnetate, stannous chloride, and tricine at pH 4-5 and room temperature results in the complex [99mTc(HYNICtide)(tricine)2], which reacts with TPPTS (50 degrees C for 30 min) to give complex 1 in > or = 90% yield as determined by radio-HPLC. Complexes 1-3 are formed as equal mixtures of two isomeric forms and are stable for > or = 6 h in the reaction mixture and in dilute solution. Both isomeric forms of complex 1 were found by a platelet-binding assay to contain the 99mTc-labeled HYNICtide and possess biological activity. The composition of these complexes was determined to be 1:1:1:1 for Tc:HYNICtide:L:tricine through a series of mixed ligand experiments on the tracer (99mTc) level. Surprisingly, this composition is maintained over a wide range of relative ligand ratios. The relative bonding capability of the three phosphine coligands to the Tc was determined by spiking various amounts of TPPDS or TPPMS into TPPTS and falls in the order TPPMS > TPPDS > TPPTS. The lipophilicity of the [99m Tc]HYNICtide complexes can be systematically varied by the choice of the phosphine and aminocarboxylate coligands. Using the combination of tricine and a phosphine ligand, HYNIC-derivatized peptides or other small molecules can be labeled with 99mTc in high specific activity and with high stability for potential use as radiopharmaceuticals.

Synthesis, stereochemistry and biological activity of some novel long alkyl chain substituted thiazolidin-4-ones and thiazan-4-one from 10-undecenoic acid hydrazide

The synthesis of four novel compounds, (i) [(11-{[2-(3-nitrophenyl)-4-oxo-1,3-thiazolidin-3-yl]amino}-11-oxoundecyl)sulfanyl]acetic acid (4), (ii) N-[5-methyl-2-(3-nitrophenyl)-4-oxo-1,3-thiazolidin-3-yl]undec-10-enamide (5), (iii) 2-[(11-{[5-methyl-2-(3-nitrophenyl)-4-oxo-1,3-thiazolidin-3-yl]amino}-11-oxoundecyl)sulfanyl]propanoic acid (6) and (iv) 3-[(11-{[2-(3-nitrophenyl)-4-oxo-1,3-thiazinan-3-yl]amino}-11-oxoundecenyl) sulfanyl]propanoic acid (8) from 10-undecenoic acid hydrazide (1) via m-nitrobenzaldehyde-10-undecenohydrazone (2) using mercaptoacetic acid in (i), 2-mercaptopropionic acid in (ii and iii) and 3-mercaptopropionic acid in (iv) is described. The uncyclized products, ({11-[(2E)-2-(3-nitrobenzylidene)hydrazino]-11-oxo-undecyl}sulfanyl)acetic acid (3) and 3-({11-[(2E)-2-(3-nitrobenzylidene)hydrazino]-11-oxoundecyl}sulfanyl)propanoic acid (7) are also obtained in (i) and (iv), respectively. The hydrazones (2), (3) and (7) exist in two conformers as synperiplanar and antiperiplanar. Structural assignment, stereochemistry and biological assays are discussed.

Identification and Structure−Activity Relationship of Phenolic Acyl Hydrazones as Selective Agonists for the Estrogen-Related Orphan Nuclear Receptors ERRβ and ERRγ

The first small molecule agonists of the estrogen-related receptors have been identified. GSK4716 (3) and GSK9089 (4) show binding to ERRgamma with remarkable selectivity over the classical estrogen receptors. Notably, in cell-based reporter assays, 3 mimics the protein ligand PGC-1alpha in activation of human ERRbeta and ERRgamma.

Synthesis and antitumor activities of a series of novel quinoxalinhydrazides

Recently, we discovered a novel class of anticancer compounds with remarkable potency in a panel of cancer cell lines. A prototype compound, SC144, showed significant in vivo efficacy in mice xenograft models of human breast cancer cells. Herein, we report on a new synthetic route to SC144 and the synthesis of several of its analogues in order to understand required features for activity. A one-step coupling of 7-fluoro-4-chloropyrrolo[1,2-a]quinoxaline with pyrazin-2-carbohydrazide improved the yield significantly. Although several of the analogues showed significant activities, modification of the heteroacyl moiety had a dramatic effect on potency.

Bisaryloxime ethers as potent inhibitors of transthyretin amyloid fibril formation

Amyloid fibril formation by the plasma protein transthyretin (TTR), requiring rate-limiting tetramer dissociation and monomer misfolding, is implicated in several human diseases. Amyloidogenesis can be inhibited through native state stabilization, mediated by small molecule binding to TTR's primarily unoccupied thyroid hormone binding sites. New native state stabilizers have been discovered herein by the facile condensation of arylaldehydes with aryloxyamines affording a bisarylaldoxime ether library. Of the library's 95 compounds, 31 were active inhibitors of TTR amyloid formation in vitro. The bisaryloxime ethers selectively stabilize the native tetrameric state of TTR over the dissociative transition state under amyloidogenic conditions, leading to an increase in the dissociation activation barrier. Several bisaryloxime ethers bind selectively to TTR in human blood plasma over the plethora of other plasma proteins, a necessary attribute for efficacy in vivo. While bisarylaldoxime ethers are susceptible to degradation by N-O bond cleavage, this process is slowed by their binding to TTR. Furthermore, the degradation rate of many of the bisarylaldoxime ethers is slow relative to the half-life of plasma TTR. The bisaryloxime ether library provides valuable structure-activity relationship insight for the development of structurally analogous inhibitors with superior stability profiles, should that prove necessary.

S-methyldithiocarbazate and its Schiff bases: evaluation of bondings and biological properties

Eight selective nitrogen-sulfur donor ligands have been synthesized from the condensation of S-methyldithiocarbazate (SMDTC) with aldehydes and ketones with a view to evaluating their antimicrobial and cytotoxic activities, and also to correlate the biological properties with the structure of the ligands. The compounds were all characterized by elemental analyses and other physicochemical techniques. SMDTC and the Schiff bases were screened for antimicrobial and cytotoxic activities. SMDTC showed very large inhibition zones (24-44 mm) against bacteria and fungi with a minimum inhibitory concentration (MIC) of 390-25,000 and 1562-6250 microg ml(-1), against different bacteria and fungi, respectively. Streptomycin and nystatin were used as the internal standards against bacteria and fungi, respectively. SMDTC along with its Schiff bases with pyridine-2-carboxaldehyde, acetylacetone and 2,3-butanedione were strongly antifungal and the MIC values were comparable to nystatin. Most of the Schiff bases were strongly cytotoxic. In particular, those with pyridine-2-carboxaldehyde and 2,3-butanedione have CD(50) values of 5.5, 1.9-2.0 microg ml(-1), respectively, against leukemic cells, while against colon cancer cells, the values were 3.7 and 2.0 microg ml(-1), respectively. The glyoxal Schiff base was strongly active only against leukemic cell with CD(50) value of 4.0 microg ml(-1). The present findings have been compared with standard drugs.

Hydrazinonaphthalene and azonaphthalene thrombopoietin mimics are nonpeptidyl promoters of megakaryocytopoiesis

High-throughput screening for the induction of a luciferase reporter gene in a thrombopoietin (TPO)-responsive cell line resulted in the identification of 4-diazo-3-hydroxy-1-naphthalenesulfonic acids as TPO mimics. Modification of the core structure and adjustment of unwanted functionality resulted in the development of (5-oxo-1,5-dihydropyrazol-4-ylidene)hydrazines which exhibited efficacies equivalent to those of TPO in several cell-based assays designed to measure thrombopoietic activity. Furthermore, these compounds elicited biochemical responses in TPO-receptor-expressing cells similar to those in TPO itself, including kinase activation and protein phosphorylation. Potencies for the best compounds were high for such low molecular weight compounds (MW < 500) with EC(50) values in the region of 1-20 nM.

Antihypertensive thiadiazoles. 1. Synthesis of some 2-aryl-5-hydrazino-1,3,4-thiadiazoles with vasodilator activity

Some 2-aryl-5-hydrazino-1,3,4-thiadiazoles have been synthesized and screened for antihypertensive activity. In general, compounds with a 2-substituted phenyl ring had higher activity than their 3- or 4-substituted counterparts or those containing heteroaryl groups. The 2-methylphenyl and 2-ethylphenyl derivatives 7 and 18 were the most potent members of the series. Preliminary studies indicated that the hypotensive action of these compounds was due to a direct relaxant effect on vascular smooth muscle.

Synthesis of a new class of 2-anilino substituted nicotinyl arylsulfonylhydrazides as potential anticancer and antibacterial agents

A series of N'-1-[2-anilino-3-pyridyl]carbonyl-1-benzenesulfonohydrazide derivatives (7a-i) was synthesized and five of them were selected by the National Cancer Institute (NCI) and evaluated for their in vitro anticancer activity. Three of the investigated compounds 7d, 7f and 7g exhibited significant anticancer activity in the primary assay and further tested against a panel of 60 human tumour cell lines. Compound 7g showed 50% growth inhibitory activity in leukaemia, melanoma, lung cancer, colon cancer, renal cancer and breast cancer cells with GI(50) value of 3.2-9.6 microM. The synthesized compounds (7a-i) were also evaluated for their antibacterial activity against various Gram-positive and Gram-negative strains of bacteria. Most of these compounds showed better inhibitory activity in comparison to the standard drugs.

Salicylhydrazine-containing inhibitors of HIV-1 integrase: implication for a selective chelation in the integrase active site

In previous studies we identified N,N'-bis(salicylhydrazine) (1) as a lead compound against purified recombinant HIV-1 integrase. We have now expanded upon these earlier observations and tested 45 novel hydrazides. Among the compounds tested, 11 derivatives exhibited 50% inhibitory concentrations (IC50) of less than 3 microM. A common feature for activity among these inhibitors is the hydroxyl group of the salicyl moiety. Although the active inhibitors must contain this hydroxyl group, other structural modifications can also influence potency. Removal of this hydroxyl group or replacement with an amino, bromo, fluoro, carboxylic acid, or ethyl ether totally abolished potency against integrase. Several asymmetric structures exhibited similar potency to the symmetric lead inhibitor 1. The superimposition of the lowest-energy conformations upon one another revealed three sites whose properties appear important for ligand binding. Site A is composed of the 2-hydroxyphenyl, the alpha-keto, and the hydrazine moieties in a planar conformation. We propose that this site could interact with HIV-1 integrase by chelation of the metal in the integrase active site as inhibition of HIV-1 integrase catalytic activity and DNA binding were strictly Mn2+-dependent. The hydrophobic sites B and C are probably responsible for complementarity of molecular shape between ligand and receptor. Our data indicate that only those compounds which possessed sites A, B, and C in a linear orientation were potent inhibitors of HIV-1 integrase. Although all the active inhibitors possessed considerable cytotoxicity and no apparent antiviral activity in CEM cells, the study presents useful information regarding ligand interaction with HIV-1 integrase protein.

Synthesis and leishmanicidal activities of 1-(4-X-phenyl)-N'-[(4-Y-phenyl)methylene]-1H-pyrazole-4-carbohydrazides

1H-pyrazole-4-carbohydrazides were synthesized and their leishmanicidal in vitro activities and cytotoxic effects were investigated. The drugs prototypes of these new compounds (ketoconazole, benznidazole, allopurinol and pentamidine) were also tested. It was found that among all the 1H-pyrazole-4-carbohydrazides derivatives examined, the most active compounds were those with X = Br, Y = NO2 (27) and X = NO2, Y = Cl (15) derivatives which showed to be most effective on promastigotes forms of L. amazonensis than on L. chagasi and L. braziliensis species. When tested against murine peritoneal macrophages as mammalian host cell controls of toxicity, 1-(4-Br-phenyl)-N'-[(4-NO(2)-phenyl)methylene]-1H-pyrazole-4-carbohydrazides (27) (EC50 = 50 microM l(-1)) and 1-(4-NO2-phenyl)-N'-[(4-Cl-phenyl)methylene]-1H-pyrazole-4-carbohydrazides (15) EC50 = 80 microM l(-1))] was reasonably toxic. However, both compounds were less toxic than pentamidine and ketoconazole. These results provide new perspectives on the development of drugs with activities against Leishmania parasite.

Hydrazide-containing inhibitors of HIV-1 integrase

Inhibitors of HIV integrase are currently being sought as potential new therapeutics for the treatment of AIDS. A large number of inhibitors discovered to date contain the o-bis-hydroxy catechol structure. In an effort to discover structural leads for the development of new HIV integrase inhibitors which do not rely on this potentially cytotoxic catechol substructure, NSC 310217 was identified using a three-point pharmacophore search based on its assigned structure N-(2-hydroxybenzoyl)-N-(2-hydroxy-3-phenoxypropyl)hydrazine (1). When a sample of NSC 310217 was obtained from the NCI repository, it was shown to exhibit potent inhibition of HIV-1 integrase (3'-processing IC50 = 0.6 microgram/mL). In work reported herein, we demonstrate that NSC 310217, rather than containing 1, which has no inhibitory potency against HIV-1 integrase, is comprised of roughly a 1:1 mixture of N-(2-hydroxybenzoyl)-N'-(2-hydroxy-3-phenoxypropyl)hydrazine (6) and N,N'-bis-salicylhydrazine 7, with all inhibitory potency residing with compound 7(IC50 = 0.7 microM for strand transfer). In subsequent structure-activity studies on 7, it is shown that removing a single amide carbonyl (compound 14, IC50 = 5.2 microM) or replacing one aromatic ring system with a naphthyl ring (compound 19, IC50 = 1.1 microM) can be accomplished with little loss of inhibitory potency. Additionally, replacing a single hydroxyl with a sulfhydryl (compound 23, IC50 = 5.8 microM) results in only moderate loss of potency. All other modifications examined, including the replacement of a single hydroxyl with an amino group (compound 22), resulted in complete loss of potency. Being potent, structurally simple, and non-catechol-containing, compounds such as 7 and 14 may provide useful leads for the development of a new class of HIV integrase inhibitor.

Catalytic Amination of 2-Substituted Pyridines with Hydrazine Derivatives

[reaction in text] Protected pyridylhydrazine derivatives were prepared in a one-step palladium-catalyzed amination reaction using chelating phosphine ligands. 2-Pyridyl chlorides, bromides, and triflates were effective electrophiles in these reactions. Di-tert-butyl hydrazodiformate was an excellent hydrazine substrate, and the resulting products were deprotected under mild conditions. Catalytic amination provides a direct route to protected bifunctional hydrazinopyridine linkers that are suitable for metal-bioconjugate syntheses.

Synthesis of some bioactive 2-bromo-5-methoxy-N'-[4-(aryl)-1,3-thiazol-2-yl]benzohydrazide derivatives

Eight novel 2-bromo-5-methoxy-N'-[4-(aryl)-1,3-thiazol-2-yl]benzohydrazide derivatives were prepared and characterized by analytical and spectral analyses. All the compounds were screened for their analgesic, antifungal and antibacterial activities and three of the compounds were screened for antiproliferative activity. Two of the newly synthesized compounds exhibited promising analgesic activity and one compound exhibited in vitro antiproliferative activity.