NVP-DPP728 (1-[[[2-[(5-cyanopyridin-2-yl)amino]ethyl]amino]acetyl]-2-cyano-(S)- pyrrolidine), a slow-binding inhibitor of dipeptidyl peptidase IV.

Inhibition of dipeptidyl peptidase IV (DPP-IV) has been proposed recently as a therapeutic approach to the treatment of type 2 diabetes. N-Substituted-glycyl-2-cyanopyrrolidide compounds, typified by NVP-DPP728 (1-[[[2-[(5-cyanopyridin-2-yl)amino]ethyl]amino]acetyl]-2-cyano-(S )-p yrrolidine), inhibit degradation of glucagon-like peptide-1 (GLP-1) and thereby potentiate insulin release in response to glucose-containing meals. In the present study NVP-DPP728 was found to inhibit human DPP-IV amidolytic activity with a K(i) of 11 nM, a k(on) value of 1.3 x 10(5) M(-)(1) s(-)(1), and a k(off) of 1.3 x 10(-)(3) s(-)(1). Purified bovine kidney DPP-IV bound 1 mol/mol [(14)C]-NVP-DPP728 with high affinity (12 nM K(d)). The dissociation constant, k(off), was 1.0 x 10(-)(3) and 1.6 x 10(-)(3) s(-)(1) in the presence of 0 and 200 microM H-Gly-Pro-AMC, respectively (dissociation t(1/2) approximately 10 min). Through kinetic evaluation of DPP-IV inhibition by the D-antipode, des-cyano, and amide analogues of NVP-DPP728, it was determined that the nitrile functionality at the 2-pyrrolidine position is required, in the L-configuration, for maximal activity (K(i) of 11 nM vs K(i) values of 5.6 to >300 microM for the other analogues tested). Surprisingly, it was found that the D-antipode, despite being approximately 500-fold less potent than NVP-DPP728, displayed identical dissociation kinetics (k(off) of 1.5 x 10(-)(3) s(-)(1)). NVP-DPP728 inhibited DPP-IV in a manner consistent with a two-step inhibition mechanism. Taken together, these data suggest that NVP-DPP728 inhibits DPP-IV through formation of a novel, reversible, nitrile-dependent complex with transition state characteristics.     

(2S,4S)-1-[2-(1,1-Dimethyl-3-oxo-3-pyrrolidin-1-yl-propylamino)acetyl]-4-fluoro-pyrrolidine-2-carbonitrile: A potent,selective, and orally bioavailable dipeptide-derived inhibitor of dipeptidyl peptidase IV

A series of 2-[3-[2-[(2S)-2-cyano-1-pyrrolidinyl]-2-oxoethylamino]-3-methyl-1-oxobutyl]-based DPP-IV inhibitors with various monocyclic amines were synthesized. The structure–activity relationships (SAR) led to the discovery of potent DPP-IV inhibitors, having IC₅₀ values of <100 nM with excellent selectivity over the closely related enzymes, DPP-II, DPP8, DPP9 and FAP (IC₅₀ > 20 μM). Of these compounds, the analogues 12a, 12h and 12i exhibited a long-lasting ex vivo DPP-IV inhibition in rats.     

(S)-gamma-(4-Aryl-1-piperazinyl)-l-prolyl]thiazolidines as a novel series of highly potent and long-lasting DPP-IV inhibitors

In the search for an inhibitor of dipeptidyl peptidase IV (DPP-IV) highly potent both in vitro and in vivo, we synthesized a series of L-prolylthiazolidine-based DPP-IV inhibitors having 4-arylpiperazine or 4-arylpiperidine at the gamma-position of the proline structure. Of these compounds, the 4-(5-nitro-2-pyridyl)piperazine analog 21e showed a sub-nanomolar (IC(50)=0.92 nmol/L) DPP-IV inhibitory activity and a long-lasting in vivo DPP-IV inhibition profile.     

1-((S)-gamma-substituted prolyl)-(S)-2-cyanopyrrolidine as a novel series of highly potent DPP-IV inhibitors

1-(Gamma-substituted prolyl)-(S)-2-cyanopyrrolidines were designed based on the predicted binding mode of the known DPP-IV inhibitor NVP-DPP728 and evaluated for their inhibitory activity. In structure-activity relationship study at the gamma-position of proline, it became clear that compounds bearing (S)-stereochemistry were 20-fold more potent than the antipode. Of these compounds, the (3,4-dicyanophenyl)amino- and (3-chloro-4-cyanophenyl)amino-derivatives showed the highest inhibitory activity.     

Synthesis,anticancer and antioxidant activities of some novel N-(benzo[d]oxazol-2-yl)-2-(7- or 5-substituted-2-oxoindolin-3-ylidene) hydrazinecarboxamide derivatives

A series of N-(benzo[d]oxazol-2-yl)-2-(7- or 5-substituted-2-oxoindolin-3-ylidene) hydrazinecarboxamide derivatives were synthesized by treating N-(benzoxazol-2-yl)hydrazinecarboxamide with different isatin derivatives. The newly synthesized compounds were characterized on the basis of spectral analyses. All the synthesized derivatives (Va-l) were screened for anticancer and antioxidant activities. The results showed the anticancer activity of test compounds against HeLa, IMR-32 and MCF-7 cancer cell lines using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. All the synthetic compounds produced a dose-dependant inhibition of growth of the cells. The IC₅₀ values of some compounds were comparable with standard anticancer agent, cisplatin. All the title compounds effectively scavenged the free radical, α,α-diphenyl-β-picryl hydrazyl. The test compounds having substitution with different halides (electron withdrawing groups) at C5 position showed more potent anticancer and antioxidant activities than those at C7 position. These results indicate that C5-substituted derivatives may be useful for developing antioxidant agents that play a protective role in many pathological conditions such as cancer, diabetes and so on.     

(3R)-3-amino-4-(2,4,5-trifluorophenyl)-N-{4-[6-(2-methoxyethoxy)benzothiazol-2-yl]tetrahydropyran-4-yl}butanamide as a potent dipeptidyl peptidase IV inhibitor for the treatment of type 2 diabetes

Novel series of 3-amino-N-(4-aryl-1,1-dioxothian-4-yl)butanamides and 3-amino-N-(4-aryltetrahydropyran-4-yl)butanamides were synthesized and evaluated as dipeptidyl peptidase IV (DPP-IV) inhibitors. Derivatives incorporating the 6-substituted benzothiazole group showed highly potent DPP-IV inhibitory activity. Oral administration of (3R)-3-amino-4-(2,4,5-trifluorophenyl)-N-{4-[6-(2-methoxyethoxy)benzothiazol-2-yl]tetrahydropyran-4-yl}butanamide (12u) reduced blood glucose excursion in an oral glucose tolerance test.     

Discovery and pharmacological characterization of N-[2-({2-[(2S)-2-cyanopyrrolidin-1-yl]-2-oxoethyl}amino)-2-methylpropyl]-2-methylpyrazolo[1,5-a]pyrimidine-6-carboxamide hydrochloride (anagliptin hydrochloride salt) as a potent and selective DPP-IV inhibitor

In the course of our program for discovery of novel DPP-IV inhibitors, a series of pyrazolo[1,5-a]pyrimidines were found to be novel DPP-IV inhibitors. We identified N-[2-({2-[(2S)-2-cyanopyrrolidin-1-yl]-2-oxoethyl}amino)-2-methylpropyl]-2-methylpyrazolo[1,5-a]pyrimidine-6-carboxamide hydrochloride (4a) and described its pharmacological profiles.     

Design and synthesis of potent amido- and benzyl-substituted cis-3-amino-4-(2-cyanopyrrolidide)pyrrolidinyl DPP-IV inhibitors

The cis-3-amino-4-(2-cyanopyrrolidide)-pyrrolidine template has been shown to afford low nanomolar inhibitors of human DPP-IV that exhibit a robust PK/PD profile. An X-ray co-crystal structure of 5 confirmed the proposed mode of binding. The potent single digit DPP-IV inhibitor 53 exhibited a preferred PK/PD profile in preclinical animal models and was selected for additional profiling.     

Design and synthesis of aminocoumarin derivatives as DPP-IV inhibitors and anticancer agents

DPP-IV “a moonlighting protein” has immerged as promising pathway to control Type 2 diabetes as well as found to play key role in earlier stages of cancer. Here we have reported design, synthesis and applications of aminocoumarin derivatives as DPP-IV inhibitors. Compounds have been synthesized and studied for their DPP-IV inhibition activity. Three compounds have shown moderate inhibition at 100 µM concentration. All compounds were also screened for their anticancer activity against A549 (Lung cancer cell line), MCF-7 (Breast cancer cell line) using MTT assay. One of the compounds has shown very good anticancer activity with IC₅₀ value 24 ± 0.1 nM against A549 cell line.     

Design, synthesis, and biological evaluation of 1-(4-sulfamylphenyl)-3-trifluoromethyl-5-indolyl pyrazolines as cyclooxygenase-2 (COX-2) and lipoxygenase (LOX) inhibitors

A series of 20 novel 1-(4-sulfamylphenyl)-3-trifluoromethyl-5-indolyl pyrazolines were designed, synthesized, and screened in vitro for anti-inflammatory activity. These compounds were designed for evaluation as dual inhibitors of cyclooxygenases (COX-1 and COX-2) and lipoxygenases (LOX-5, LOX-12, and LOX-15) that are responsible for inflammation and pain. All pyrazoline molecules prepared are optically active and compounds that are more potent in COX-2 inhibitory activity (5a and 5f) were resolved by chiral column and each enantiomer was tested for cyclooxygenase inhibitory activity. Molecular modeling and comparison of molecular models of 5a enantiomers with that of celecoxib model shows that 5a (enantiomer-1) and 5a (enantiomer-2) have more hydrogen bonding interactions in the catalytic domain of COX-2 enzyme than celecoxib. Compounds 5a, 5e, and 5f showed moderate to good LOX-5 and LOX-15 inhibitory activity and this is comparable to that of celecoxib and more potent than rofecoxib.     

Dipeptidyl peptidase IV inhibitory and antioxidative properties of milk protein-derived dipeptides and hydrolysates

Selected synthetic dipeptides and milk protein hydrolysates were evaluated for their dipeptidyl peptidase IV (DPP-IV) inhibitory properties, and their superoxide (SO) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activities. DPP-IV inhibition was seen with eight out of the twelve dipeptides and 5 of the twelve hydrolysates studied. Trp-Val inhibited DPP-IV, however, inhibition was not observed with the reverse peptide Val-Trp. The most potent hydrolysate inhibitors were generated from casein (CasH2) and lactoferrin (LFH1). Two Trp containing dipeptides, Trp-Val and Val-Trp, and three lactoferrin hydrolysates scavenged DPPH. The dipeptides had higher SO EC₅₀ values compared to the milk protein hydrolysates (arising from three lactoferrin and one whey protein hydrolysates). Higher molecular mass fractions of the milk protein hydrolysates were associated with the SO scavenging activity. Trp-Val and one lactoferrin hydrolysate (LFH1) were multifunctional displaying both DPP-IV inhibitory and antioxidant (SO and DPPH scavenging) activities. These compounds may have potential as dietary ingredients in the management of type 2 diabetes by virtue of their ability to scavenge reactive oxygen species and to extend the half-life of incretin molecules.     

Synthesis and evaluation of novel N-H and N-substituted indole-2- and 3-carboxamide derivatives as antioxidants agents

We have previously reported on the synthesis of novel indole derivatives where some compounds showed significant antioxidant activity. Here, we report the synthesis of novel N-H and N-substituted indole-2- and 3-carboxamide derivatives and investigated their antioxidant role in order to identify structural characteristics responsible for activity. Although all compounds showed a strong inhibitory (95-100%) effect on superoxide anion (SOD) only compounds 4, 5 and 6 showed simliar potency for the inhibition of lipid peroxidation (81-94%) which revealed that compounds 4, 5 and 6 possessed highly potent antioxidant properties. Substitution in the 1-position of the indole ring caused the significant differences between the activity results regarding lipid peroxidation inhibition.     

Synthesis, anticancer activity and pharmacokinetic analysis of 1-[(substituted 2-alkoxyquinoxalin-3-yl)aminocarbonyl]-4-(hetero)arylpiperazine derivatives

Based on the anticancer activity of novel quinoxalinyl-piperazine compounds, 1-[(5 or 6-substituted alkoxyquinoxalinyl)aminocarbonyl]-4-(hetero)arylpiperazine derivatives published in Bioorg. Med. Chem.2010, 18, 7966, we further explored the synthesis of 7 or 8-substituted quinoxalinyl piperazine derivatives. From in vitro studies of the newly synthesized compounds using human cancer cell lines, we identified some of the 8-substituted compounds, for example 6p, 6q and 6r, which inhibited the proliferation of various human cancer cells at nanomolar concentrations. Compound 6r, in particular, showed the lowest IC(50) values, ranging from 6.1 to 17nM, in inhibition of the growth of cancer cells, which is better than compound 6k (compound 25 in the reference cited above). In order to select and develop a leading compound among the quinoxaline compounds with substitutions on positions 5, 6, 7 or 8, the compounds comparable to compound 6k in in vitro cancer cell growth inhibition were chosen and their pharmacokinetic properties were evaluated in rats. In these studies, compound 6k showed the highest oral bioavailability of 83.4%, and compounds 6j and 6q followed, with 77.8% and 57.6%, respectively. From the results of in vitro growth inhibitory activities and the pharmacokinetic study, compound 6k is suggested for further development as an orally deliverable anticancer drug.     

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.     

Synthesis, anticancer and antioxidant activities of some novel N-(benzo[d]oxazol-2-yl)-2-(7- or 5-substituted-2-oxoindolin-3-ylidene) hydrazinecarboxamide derivatives

A series of N-(benzo[d]oxazol-2-yl)-2-(7- or 5-substituted-2-oxoindolin-3-ylidene) hydrazinecarboxamide derivatives were synthesized by treating N-(benzoxazol-2-yl)hydrazinecarboxamide with different isatin derivatives. The newly synthesized compounds were characterized on the basis of spectral analyses. All the synthesized derivatives (Va-l) were screened for anticancer and antioxidant activities. The results showed the anticancer activity of test compounds against HeLa, IMR-32 and MCF-7 cancer cell lines using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. All the synthetic compounds produced a dose-dependant inhibition of growth of the cells. The IC(50) values of some compounds were comparable with standard anticancer agent, cisplatin. All the title compounds effectively scavenged the free radical, α,α-diphenyl-β-picryl hydrazyl. The test compounds having substitution with different halides (electron withdrawing groups) at C5 position showed more potent anticancer and antioxidant activities than those at C7 position. These results indicate that C5-substituted derivatives may be useful for developing antioxidant agents that play a protective role in many pathological conditions such as cancer, diabetes and so on.     

Synthesis and antitumoral activity of novel 3-(2-substituted-1,3,4-oxadiazol-5-yl) and 3-(5-substituted-1,2,4-triazol-3-yl) beta-carboline derivatives

Several novel 1-substituted-phenyl beta-carbolines bearing the 2-substituted-1,3,4-oxadiazol-5-yl and 5-substituted-1,2,4-triazol-3-yl groups at C-3 were synthesized and evaluated for their in vitro anticancer activity. The assay results pointed thirteen compounds with growth inhibition effect (GI(50)<100 microM) for all eight different types of human cancer cell lines tested. The beta-carbolines 7a and 7h, bearing the 3-(2-metylthio-1,3,4-oxadiazol-5-yl) group, displayed high selectivity and potent anticancer activity against ovarian cell line with GI(50) values lying in the nanomolar concentration range (GI(50)=10 nM for both compounds). The 1-(N,N-dimethylaminophenyl)-3-(5-thioxo-1,2,4-triazol-3-yl) beta-carboline (8g) was the most active compound, showing particular effectiveness on lung (GI(50)=0.06 microM), ovarian and renal cell lines. The potent anticancer activity presented for synthesized compounds 7a, 7h, and 8g, together with their easiness of synthesis, makes these compounds promising anticancer agents.     

Synthesis,biological evaluations and computational studies of N-(3-(-2-(7-Chloroquinolin-2-yl)vinyl) benzylidene)anilines as fungal biofilm inhibitors

In the present investigation, new chloroquinoline derivatives bearing vinyl benzylidene aniline substituents at 2nd position were synthesized and screed for biofilm inhibitory, antifungal and antibacterial activity. The result of biofilm inhibition of C. albicans suggested that compounds 5j (IC₅₀ value?=?51.2?μM) and 5a (IC₅₀ value?=?66.2?μM) possess promising antibiofilm inhibition when compared with the standard antifungal drug fluconazole (IC₅₀?=?40.0?μM). Two compounds 5a (MIC?=?94.2?μg/mL) and 5f (MIC?=?98.8?μg/mL) also exhibited good antifungal activity comparable to standard drug fluconazole (MIC?=?50.0?μg/mL). The antibacterial screening against four strains of bacteria viz. E. coli, P. aeruginosa, B. subtilis, and S. aureus suggested their potential antibacterial activity and especially all the compounds except 5g were found more active than the standard drug ciprofloxacin against B. subtilis. To further gain insights into the possible mechanism of these compounds in biofilm inhibition through the agglutinin like protein (Als), molecular docking and molecular dynamics simulation studies were carried out. Molecular modeling studies suggested the clear role in inhibition of this protein and the resulting biofilm inhibitory activity.     

Synthesis of base substituted 2-hydroxy-3-(purin-9-yl)-propanoic acids and 4-(purin-9-yl)-3-butenoic acids

Alkylation of 6-chloropurine and 2-amino-6-chloropurine with bromoacetaldehyde diethyl acetal afforded 6-chloro-9-(2,2-diethoxyethyl)purine (3a) and its 2-amino congener (3b). Treatment of compounds 3 with primary and secondary amines gave the N6-substituted adenines (5a-5c) and 2,6-diaminopurines (5d-5f). Hydrolysis of 3 resulted in hypoxanthine (6a) and guanine (6b) derivatives, while their reaction with thiourea led to 6-sulfanylpurine (7a) and 2-amino-6-sulfanylpurine (7b) compounds. Treatment with diluted acid followed by potassium cyanide treatment and acid hydrolysis afforded 6-substituted 3-(purin-9-yl)- and 3-(2-aminopurin-9-yl)-2-hydroxypropanoic acids (8-10). Reaction of compounds 3 with malonic acid in aqueous solution gave exclusively the product of isomerisation, 6-substituted 4-(purin-9-yl)-3-butenoic acids (15).     

(S)-gamma-(Arylamino)prolyl]thiazolidine compounds as a novel series of potent and stable DPP-IV inhibitors

Dipeptidyl peptidase-IV (DPP-IV) inhibitors, or glucagon-like peptide-1 (GLP-1) enhancers, are looked to as a potential new class of antidiabetic agents. In particular, potent and long-acting inhibitors might offer advantages in exploiting DPP-IV inhibition. The series of [(S)-gamma-(arylamino)prolyl]-(S)-2-cyanopyrrolidine compounds on which we reported previously has a highly potent inhibitory activity but seemed to be unstable in neutral aqueous solution. Here, we describe [(S)-gamma-(arylamino)prolyl]thiazolidine compounds as a novel series of potent and stable DPP-IV inhibitors. They are the thiazolidine analogs of [(S)-gamma-(arylamino)prolyl]-(S)-2-cyanopyrrolidine but with the electrophilic nitrile removed to improve chemical stability in aqueous solution. Of the compounds investigated in the present study, the [((S)-gamma-3,4-dicyanophenylamino)prolyl]thiazolidine 12 m was the most potent. The structure-activity relationship (SAR) of the gamma-substituent in the proline moiety of the thiazolidide was similar to that obtained with the (S)-2-cyanopyrrolidide. The gamma-substituent in the proline moiety of both the (S)-2-cyanopyrrolidide and the thiazolidide may engage with the S(2) binding pocket of DPP-IV and thereby achieve hydrophobic interaction in the same manner. Based on pharmacokinetic experiments in rats, the representative compound 11, which displayed high oral bioavailability (BA=83.9%) and long half-life in plasma (t(1/2)=5.27 h), was found to have an excellent pharmacokinetic profile.     

Synthesis, antibacterial activity, and quantitative structure-activity relationships of new (Z)-2-(nitroimidazolylmethylene)-3(2H)-benzofuranone derivatives

A new series of (Z)-2-(1-methyl-5-nitroimidazole-2-ylmethylene)-3(2H)-benzofuranones (11a-p) and (Z)-2-(1-methyl-4-nitroimidazole-5-ylmethylene)-3(2H)-benzofuranones (12a-m) were synthesized and assayed for their antibacterial activity against Gram-positive and Gram-negative bacteria. Most of the 5-nitroimidazole analogues (11a-p) showed a remarkable inhibition of a wide spectrum of Gram-positive bacteria (Staphylococcus aureus, Streptococcus epidermidis, MRSA, and Bacillus subtilis) and Gram-negative Klebsiella pneumoniae, whereas 4-nitroimidazole analogues (12a-m) were not effective against selected bacteria. The quantitative structure-activity relationship investigations were applied to find out the correlation between the experimentally evaluated activities with various parameters of the compounds studied. The QSAR models built in this work had reasonable predictive power and could be explained by the observed trends in activities.