Design, synthesis, and biological evaluation of triazolopiperazine-based beta-amino amides as potent, orally active dipeptidyl peptidase IV (DPP-4) inhibitors

Various beta-amino amides containing triazolopiperazine heterocycles have been prepared and evaluated as potent, selective, orally active dipeptidyl peptidase IV (DPP-4) inhibitors. These compounds display excellent oral bioavailability and good overall pharmacokinetic profiles in preclinical species. Moreover, in vivo efficacy in an oral glucose tolerance test in lean mice is demonstrated.     

Metabolic flux analysis of the phenylpropanoid pathway in elicitor-treated potato tuber tissue

The effects of beta-1,3-oligosaccharide elicitor on the metabolism of phenylpropanoids in potato tuber were analyzed quantitatively, by monitoring the time-dependent changes in the levels of seven compounds. The elicitor treatment caused an increase in the pool size of octopamine and tyramine amides (N-p-coumaroyloctopamine, N-feruloyloctopamine, N-p-coumaroyltyramine and N-feruloyltyramine), as well as a decrease in that of chlorogenic acid and putrescine amides (caffeoylputrescine and feruloylputrescine). An analysis of metabolic flux using stable isotope labeling and liquid chromatography-spectrometry (LC-MS) detection clearly demonstrated that the changes in the pool size of these compounds were correlated with the changes in their flux for biosynthesis (Jin) upon elicitor treatment. The increase in Jin in the cases of octopamine and tyramine amides was accompanied by an increase in flux for the transformation (Jout), indicating a rapid turnover of these compounds in the elicitor-treated tuber tissue. The result of the flux analysis indicated that the actual activation of the biosynthesis of octopamine and tyramine amides after the elicitor treatment was greater than that estimated from the changes in their levels in the potato tissue. These findings suggest that these amide compounds and their metabolic derivatives play an important role in the defense-related metabolism of phenylpropanoids in potato.     

Synthesis, in vitro and in vivo antimycobacterial activities of diclofenac acid hydrazones and amides

Various diclofenac acid hydrazones and amides were synthesized and evaluated for in vitro and in vivo antimycobacterial activities against Mycobacterium tuberculosis. Preliminary results indicated that most of the compounds demonstrated better in vitro antimycobacterial activity (MIC: 0.0383-7.53 microM) than diclofenac (MIC: 21.10 microM) and ciprofloxacin (MIC: 9.41 microM). Among the synthesized compounds, 1-cyclopropyl-6-fluoro-8-methoxy-7-[[N4-(2-(2-(2,6-dichlorophenylamino)phenyl)acetyl)-3-methyl]-N1-piperazinyl]-4-oxo-1,4-dihydro-3-quinoline carboxylic acid (5d) was found to be the most active compound in vitro with MIC of 0.0383 microM and was more potent than first line antitubercular drug isoniazid (MIC: 0.1822 microM). In the in vivo animal model 5d decreased the bacterial load in lung and spleen tissues with 2.42- and 3.66-log10 protections, respectively, at 25 mg/kg body weight.     

Characterization of cross-linked hydroxycinnamic acid amides isolated from potato common scab lesions

Four feruloyl amides, N-trans-feruloyloctopamine (1), N-cis-feruloyloctopamine (2), N-trans-feruloyltyramine (3), N-cis-feruloyltyramine (4), a cross-linked N-trans-feruloyltyramine dimer (5), and a cross-linked N-cis-feruloyltyramine dimer (6) were isolated from potato common scab lesions. The compounds were purified by TLC and characterized by a combination of (1)H and (13)C NMR spectroscopic techniques. The presence of an accompanying minor complex of cross-linked dimers containing both feruloyltyramines and feruloyloctopamines was also demonstrated. This is the first characterization of cross-linked hydroxycinnamic acid amides associated with wound healing in potato (Solanum tuberosum) tubers.     

Anthranilic sulfonamide CCK1/CCK2 dual receptor antagonists II: Tuning of receptor selectivity and in vivo efficacy

In the previous article we demonstrated how certain CCK2R-selective anthranilic amides could be structurally modified to afford high-affinity, selective CCK1R activity. We now describe our efforts at modulating and optimizing the CCK1R and CCK2R affinities aimed at producing compounds with good pharmacokinetics properties and in vivo efficacy in rat models of gastric acid and pancreatic amylase secretion.     

Production of coumaroylserotonin and feruloylserotonin in transgenic rice expressing pepper hydroxycinnamoyl-coenzyme A:serotonin N-(hydroxycinnamoyl)transferase

Transgenic rice (Oryza sativa) plants were engineered to express a N-(hydroxycinnamoyl)transferase from pepper (Capsicum annuum), which has been shown to have hydroxycinnamoyl-CoA:tyramine N-(hydroxycinnamoyl)transferase activity, a key enzyme in the synthesis of hydroxycinnamic acid amides, under the control of constitutive maize (Zea mays) ubiquitin promoter. The transgenic rice plants require foliar application of amines to support synthesis of hydroxycinnamic acid amides, suggestive of limiting amine substrates in rice shoots. In addition, when T2 homozygous transgenic rice plants were grown in the presence of amines or phenolic acids, two novel compounds were exclusively identified in the leaves of the transgenic plants. These compounds eluted earlier than p-coumaroyltyramine and feruloyltyramine during HPLC chromatography and were identified as p-coumaroylserotonin and feruloylserotonin by liquid chromatography/mass spectrometry and other methods. To test whether the unpredicted production of serotonin derivatives is associated with the pepper N-(hydroxycinnamoyl)transferase, the substrate specificity of the pepper enzyme was analyzed again. Purified recombinant pepper N-(hydroxycinnamoyl)transferase exhibited a serotonin N-hydroxycinnamoyltransferase (SHT) activity, synthesized p-coumaroylserotonin and feruloylserotonin in vitro, and demonstrated a low K(m) for serotonin. SHT activity was inhibited by 10 to 50 mm tyramine. In addition, SHT activity was predominantly found in the root tissues of wild-type rice in parallel with the synthesis of serotonin derivatives, suggesting that serotonin derivatives are synthesized in the root of rice. This is the first report of SHT activity and the first demonstration, to our knowledge, that serotonin derivatives can be overproduced in vivo in transgenic rice plants that express serotonin N-(hydroxycinnamoyl)transferase.     

IRAK-4 inhibitors. Part 1: a series of amides

The synthesis and profile of a series of amides are described. Some of these compounds were potent IRAK-4 inhibitors and two examples were evaluated in vivo.     

Pyrazole antagonists of the CB1 receptor with reduced brain penetration

Type 1 cannabinoid receptor (CB1) antagonists might be useful for treating obesity, liver disease, metabolic syndrome, and dyslipidemias. Unfortunately, inhibition of CB1 in the central nervous system (CNS) produces adverse effects, including depression, anxiety and suicidal ideation in some patients, which led to withdrawal of the pyrazole inverse agonist rimonabant (SR141716A) from European markets. Efforts are underway to produce peripherally selective CB1 antagonists to circumvent CNS-associated adverse effects. In this study, novel analogs of rimonabant (1) were explored in which the 1-aminopiperidine group was switched to a 4-aminopiperidine, attached at the 4-amino position (5). The piperidine nitrogen was functionalized with carbamates, amides, and sulfonamides, providing compounds that are potent inverse agonists of hCB1 with good selectivity for hCB1 over hCB2. Select compounds were further studied using in vitro models of brain penetration, oral absorption and metabolic stability. Several compounds were identified with predicted minimal brain penetration and good metabolic stability. In vivo pharmacokinetic testing revealed that inverse agonist 8c is orally bioavailable and has vastly reduced brain penetration compared to rimonabant.     

5-Chloroindoloyl glycine amide inhibitors of glycogen phosphorylase: synthesis, in vitro, in vivo, and X-ray crystallographic characterization

The synthesis, in vitro, and in vivo biological characterization of a series of achiral 5-chloroindoloyl glycine amide inhibitors of human liver glycogen phosphorylase A are described. Improved potency over previously reported compounds in cellular and in vivo assays was observed. The allosteric binding site of these compounds was shown by X-ray crystallography to be the same as that reported previously for 5-chloroindoloyl norstatine amides.     

Synthesis and anticonvulsant activity of a class of 2-amino 3-hydroxypropanamide and 2-aminoacetamide derivatives

Several studies have demonstrated that N-substituted amino acid derivatives exhibit weak anticonvulsant activities in vivo. In the present study, a series of amides of aminoacids structurally related to aminoacetamide have been synthesised and investigated for anticonvulsant activity. Among the molecules investigated, those containing a bicyclic (tetralinyl, indanyl) group linked to the aminoacetamide chain (40, 47 and 59) were among the most active as anticonvulsants (ED50 > 10, <100 mg/kg after oral administration) against tonic seizures in the mouse maximal electroshock, bicuculline and picrotoxin tests at doses devoid of neurotoxic activity. Altogether, these results suggest the described compounds as a class of orally available anticonvulsants. The ability of these compounds to partially block veratridine-induced aspartate efflux from rat cortical synaptosomes suggests that their anticonvulsant activity may be only partly the consequence of an interaction with neuronal voltage-dependent sodium channels. Some of the most potent compounds appear worthy of a further investigation aimed at assessing their anticonvulsant activity in other models and at elucidating the underlying mechanism of action.     

Biphenyl amide p38 kinase inhibitors 3: Improvement of cellular and in vivo activity

The biphenyl amides (BPAs) are a novel series of p38α MAP kinase inhibitor. The optimisation of the series to give compounds that are potent in an in vivo disease model is discussed. SAR is presented and rationalised with reference to the crystallographic binding mode.     

Substituted pyrrolidine-2,4-dicarboxylic acid amides as potent dipeptidyl peptidase IV inhibitors

A series of substituted pyrrolidine-2,4-dicarboxylic acid amides were synthesized as potential antidiabetic agents, and many of them showed good in vitro DPP-IV inhibition (IC50 = 2-250 nM) with selectivity over DPP-II, DPP8, and FAP enzymes. Selected compounds 8c and 11a showed in vivo plasma DPP-IV inhibition after oral administration in Wistar rats.     

Food-borne amines and amides as potential precursors of endogenous carcinogens

This paper reviews the experimental results of our research in the past several years and other related papers that have been directed toward the occurrence, biotransformation and epidemiological significance of carcinogenic N-nitroso compounds in biosphere. Endogenous carcinogens are a group of cancer-causing compounds produced in vivo from harmless precursors. This category has been exemplified by the well-known carcinogens, N-nitroso compounds. The significance of naturally occurring amines and amides as precursors of carcinogenic N-nitroso compounds in vivo and their implication in the incidence of human cancer have been investigated and emphasized. Extremely high levels of trimethylamine-N-oxide and dimethylamine were detected in squids and other seafoods. More than 90% of trimethylamine-N-oxide were converted to dimethylamine and trimethylamine on pyrolysis. Low levels of dimethylamine and methylamine were also detected in the fermented soybean products, wines and sauces. Both dimethylamine and trimethylamine are excellent precursors of dimethylnitrosamine. Several naturally occurring aromatic amines especially 2-carboline derivatives such as harman, norharman, harmaline, harmalol, harmine and harmol are mutagenic and become more mutagenic to Salmonella typhimurium after nitrosation. Appreciable amounts of piperidine were detected in the popular spice white and black pepper powders. Under acidic condition, piperidine reacts readily with nitrite to form carcinogenic N-nitroso-piperidine. N-Nitrosophenacetin was formed from the reaction of nitrite with the amide drug phenacetin. This new compound showed strong mutagenicity to Salmonella typhimurium and Sarcina lutea and strong teratogenic activity to Leghorn chicken embryos. Studies have shown that the majority of N-nitroso compounds in the body come from in vivo conversion. Most investigators believe that this endogenous pool of N-nitroso compounds may prove to be a major exposure route in man. The presence of naturally occurring amines and amides in the diet then becomes one of the crucial limiting steps in the formation of endogenous N-nitroso compounds in vivo.     

Discovery of novel isoxazolines as anti-tuberculosis agents

Nitrofuranyl isoxazolines with increased proteolytic stability over nitrofuranyl amides were designed and synthesized leading to discovery of several compounds with potent in vitro anti-tuberculosis activity. However, their in vivo activity was limited by high protein binding and poor distribution. Consequently, a series of non-nitrofuran containing isoxazolines were prepared to determine if the core had residual anti-tuberculosis activity. This led to the discovery of novel isoxazoline 12 as anti-tuberculosis agent with a MIC(90) value of 1.56microg/mL.     

Induction of hydroxycinnamic acid amides and tryptophan by jasmonic acid, abscisic acid and osmotic stress in barley leaves

The effects of jasmonic acid (JA) and abscisic aid (ABA) on secondary metabolism in barley (Hordeum vulgare L.) were investigated. Treatment with JA at 100 microM for 48 h induced accumulation of four compounds in barley primary leaves. The accumulation of these compounds was also observed after treatment with ABA at 100 microM. The induced compounds were identified as p-coumaroylputrescine, p-coumaroylagmatine, p-coumaroyl-3-hydroxyagmatine and tryptophan by spectroscopic methods. The profiles of compounds induced by application of JA and ABA were different. JA exhibited stronger inducing activity for hydroxycinnamic acid amides than ABA, while ABA was more active in tryptophan accumulation. The major hydroxycinnamic acid amides in JA- and ABA-treated leaves were p-coumaroylagmatine and p-coumaroyl-3-hydroxyagmatine, respectively. These differences suggested that JA and ABA act in distinct modes. The induction of these compounds was also observed in leaf segments treated with 1 M sorbitol and glucose. These findings suggested that JA and ABA are involved in accumulation of hydroxycinnamic acid amides and tryptophan in response to osmotic stress in barley.     

Some Active Derivatives of Penicillin

The antibacterial activities of a number of amide derivatives of penicillin against both penicillin-sensitive and penicillin-resistant cultures were determined. Several of them were found to possess significant inhibitory activity against certain gram-positive bacteria. The amides, although resistant to the destructive action of beta-lactamase, did not protect G in competitive experiments. One derivative, the O-benzylhydroxamide of penicillin G, was active against six or eight penicillin-resistant strains of Staphylococcus aureus (minimal inhibitory concentration, 0.2 mug/ml or less), but was found to have only a minimal in vivo activity against mouse Streptococcus infections.     

Amine-constrained pyridazinone histamine H₃ receptor antagonists

Pyridazinone 1 was recently reported as a potent H(3)R antagonist with good drug-like properties and in vivo activity. A series of constrained amine analogs of 1 was synthesized to identify compounds with improved pharmacokinetic profiles. From these efforts, a new class of (S)-2-pyrrolidin-1-ylmethyl-1-pyrrolidinyl amides was identified.     

Bile acid derivatives of 5-amino-1,3,4-thiadiazole-2-sulfonamide as new carbonic anhydrase inhibitors: synthesis and investigation of inhibition effects

Bile acid amides (cholan-24-amides) of 5-substituted 1,3,4-thiadiazole-2-sulfonamide have been prepared from lithocholic, deoxycholic, cholic and dehydrocholic acids. Besides, the alcohol functional groups on the cholane ring systems were protected with acetyl group. Amides of the protected cholanes of lithocholic and cholic acids were also synthesized. Later, inhibition effects of these compounds on human carbonic anhydrase isozymes (HCA-I and II) have been investigated in vitro. For the most active compounds, inhibition constants ranged from 66 to 190nM for HCA-II with I(50) (molarity of inhibitor producing a 50% inhibition of CA activity). In addition, in vivo studies were performed for the synthesized compounds in Sprague-Dawley rats. The compounds (11 and 18) showed especially significant inhibition efficacy (p<0.001).     

Discovery of liver-targeted inhibitors of stearoyl-CoA desaturase (SCD1)

Inhibitors based on a benzo-fused spirocyclic oxazepine scaffold were discovered for stearoyl-coenzyme A (CoA) desaturase 1 (SCD1) and subsequently optimized to potent compounds with favorable pharmacokinetic profiles and in vivo efficacy in reducing the desaturation index in a mouse model. Initial optimization revealed potency preferences for the oxazepine core and benzylic positions, while substituents on the piperidine portions were more tolerant and allowed for tuning of potency and PK properties. After preparation and testing of a range of functional groups on the piperidine nitrogen, three classes of analogs were identified with single digit nanomolar potency: glycine amides, heterocycle-linked amides, and thiazoles. Responding to concerns about target localization and potential mechanism-based side effects, an initial effort was also made to improve liver concentration in an available rat PK model. An advanced compound 17m with a 5-carboxy-2-thiazole substructure appended to the spirocyclic piperidine scaffold was developed which satisfied the in vitro and in vivo requirements for more detailed studies.     

In Vitro Antioxidant Profile of Phenolic Acid Derivatives

Several caffeic acid esters isolated from propolis exhibit interesting antioxidant properties, but their in vivo use is compromised by hydrolysis of the ester bond in the gastrointestinal tract. Therefore, a series of caffeic acid amides were synthesized and their in vitro antioxidant profile was determined. A series of hydroxybenzoic acids, hydroxycinnamic acids, and the synthesized caffeic acid amides were tested for both their 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging and microsomal lipid peroxidation-inhibiting activity. Some of the highly active antioxidants were further tested by means of electron paramagnetic resonance for their hydroxyl radical scavenging activity. Since a promising antioxidant compound should show a lipid peroxidation-inhibiting activity at micromolar level and a low cytotoxicity, the cytotoxicity of the phenolic compounds was also studied. In all the assays used, the caffeic acid anilides and the caffeic acid dopamine amide showed an interesting antioxidant activity.