Nicotinamide Adenine Dinucleotide Analogues Research Articles

Synthesis, Biological, and Computational Evaluations of Conformationally Restricted NAD-Mimics as Discriminant Inhibitors of Human NMN-Adenylyltransferase Isozymes.

Nicotinamide adenine dinucleotide (NAD) cofactor metabolism plays a significant role in cancer development. Tumor cells have an increased demand for NAD and ATP to support rapid growth and proliferation. Limiting the amount of available NAD by targeting critical NAD biosynthesis enzymes has emerged as a promising anticancer therapeutic approach. In mammals, the enzyme nicotinamide/nicotinic acid adenylyltransferase (NMNAT) catalyzes a crucial downstream reaction for all known NAD synthesis routes. Novel nicotinamide/nicotinic acid adenine dinucleotide (NAD/NaAD) analogues 1-4, containing a methyl group at the ribose 2'-C and 3'-C-position of the adenosine moiety, were synthesized as inhibitors of the three isoforms of human NMN-adenylyltransferase, named hNMNAT-1, hNMNAT-2, and hNMNAT-3. An NMR-based conformational analysis suggests that individual NAD-analogues (1-4) have distinct conformational preferences. Biological evaluation of dinucleotides 1-4 as inhibitors of hNMNAT isoforms revealed structural relationships between different conformations (North-anti and South-syn) and enzyme-inhibitory activity. Among the new series of NAD analogues synthesized and tested, the 2'-C-methyl-NAD analogue 1 (Ki = 15 and 21 µM towards NMN and ATP, respectively) emerged as the most potent and selective inhibitor of hNMNAT-2 reported so far. Finally, we rationalized the in vitro bioactivity and selectivity of methylated NAD analogues with in silico studies, helping to lay the groundwork for rational scaffold optimization.

Photoinduced Electron Transfer from a 1,4,5,6-Tetrahydro Nicotinamide Adenine Dinucleotide (Phosphate) Analogue to Oxidized Flavin in an Ene-Reductase Flavoenzyme.

Recent reports have described the use of ene-reductase flavoenzymes to catalyze non-natural photochemical reactions. These studies have focused on using reduced flavoenzyme, yet oxidized flavins have superior light harvesting properties. In a binary complex of the oxidized ene-reductase pentaerythritol tetranitrate reductase with the nonreactive nicotinamide coenzyme analogs 1,4,5,6-tetrahydro NAD(P)H, visible photoexcitation of the flavin mononucleotide (FMN) leads to one-electron transfer from the NAD(P)H4 to FMN, generating a NAD(P)H4 cation radical and anionic FMN semiquinone. This electron transfer occurs in ∼1 ps and appears to kinetically outcompete reductive quenching from aromatic residues in the active site. Time-resolved infrared measurements show that relaxation processes appear to be largely localized on the FMN and the charge-separated state is short-lived, with relaxation, presumably via back electron transfer, occurring over ∼3-30 ps. While this demonstrates the potential for non-natural photoactivity, useful photocatalysis will likely require longer-lived excited states, which may be accessible by enzyme engineering and/or a judicious choice of substrate.

Gram-scale biocatalytic preparation of the non-natural cofactor nicotinamide cytosine dinucleotide

A simple and fast method of preparation of non-natural nicotinamide adenine dinucleotide (NAD) analog nicotinamide cytosine dinucleotide (NCD) was developed. NCD synthetase (NcdS-1) was developed from nicotinic acid mononucleotide adenylyltransferase (NadD) with higher catalytic efficiency towards nicotinamide mononucleotide (NMN) and cytidine triphosphate (CTP). Reaction composition was optimized with inorganic pyrophosphatase (PPase) from E. coli to achieve near quantitative conversion of substrates. A Scalable purification procedure was determined to achieve a fast 4.19 g NCD preparation of 96 % purity.

Abstract 1888: Anti-CD38 interference with blood compatibility testing: Differentiating isatuximab and daratumumab via functional epitope mapping

Abstract Introduction: Two anti-CD38 monoclonal antibodies (mAb) are approved for the treatment of multiple myeloma: isatuximab (Isa) and daratumumab (Dara); binding to CD38 on red blood cells (RBCs) results in false positive agglutination on indirect antiglobulin tests (IATs). Compared to Dara, which interferes with IATs in nearly 100% of patients, Isa interfered in 67/99 (67%) patients in the Phase 3 ICARIA-MM (NCT02990338) study and 95/150 (63%) patients in the Phase 3 IKEMA (NCT0327585) study. We sought to understand differences between the binding abilities of Isa and Dara to CD38 on RBCs. Experimental Procedures: In vitro binding experiments in RBCs were performed following pretreatment of RBCs isolated from healthy donors +/- a mouse anti-human CD38 mAb (clone HB-7 or AT13/5) or a nicotinamide adenine dinucleotide (NAD) analog (irreversible CD38 inhibitor) before incubation with Isa, Dara, or control human IgG (hIgG). RBC surface bound CD38 antibodies were detected with fluorophore conjugated secondary antibodies and quantified by flow cytometry, imaging or mass spectrometry. Binding of Isa to recombinant human CD38 (rhCD38) pretreated with HB-7 or an NAD analog was quantified by Surface Plasmon Resonance (SPR). Ex vivo IAT was performed on plasma samples spiked with Isa or Dara. Results: In vitro testing in the absence of human plasma showed that incubation of RBCs with Dara but not Isa resulted in a dose-dependent increase in RBC binding. The binding specificity of Dara was demonstrated by treatment with HB-7, an anti-CD38 mAb that recognizes epitopes that overlap with Dara but not Isa binding. Flow cytometry, confocal microscopy, SPR and mass spectrometry showed HB-7 had a competitive effect on Dara binding and induced Isa to bind to CD38 without competition. Pretreatment of RBCs with another anti-CD38 mAb AT13/5 or an NAD analog also induced Isa binding to RBCs. The NAD analog is an irreversible CD38 inhibitor that stabilizes CD38 dimer conformation. SPR demonstrated that pretreatment with HB-7 or the NAD analog may enhance dimer formation increasing Isa binding affinity to rhCD38. These results indicate that CD38 conformational changes caused by anti-CD38 antibodies or the NAD analog may facilitate Isa-binding to RBC-expressing CD38. In the ex vivo IAT, except for gel testing in which both Isa and Dara were panreactive, including all other IAT methods Dara reacted with many more cells, and reactions were stronger than Isa at all concentrations tested. Conclusions: In this study, we confirmed that both Isa and Dara interfere with IATs but at different magnitudes. This reflects distinct mechanisms of CD38 binding. In the absence of human plasma, CD38 on RBCs can be directly recognized by Dara while Isa requires a cofactor, such as an anti-CD38 antibody or an NAD analog. Future studies are essential to characterize the impact of human plasma on Isa binding to RBCs-expressing CD38. Citation Format: Zhili Song, Olivier Bedel, Bailin Zhang, Joern Hopke, Gejing Deng, Sandrine Macé, Marielle Chiron, Francisco Adrian, Taro Fukao, Frank Basile, France Pirenne, Makoto Okuda, Morvarid Moayeri, Btissam Chami, Yoko Hidaka, Ashok Nambiar, Thomas Martin, Chen Zhu. Anti-CD38 interference with blood compatibility testing: Differentiating isatuximab and daratumumab via functional epitope mapping [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1888.

Synthesis of proteogenic amino acid-based NAD analogs

Nicotinamide adenine dinucleotide (NAD) analogs have been prepared for diverse applications especially as alternative redox cofactors for NAD-dependent enzymes. Herein, 14 NAD analogs based on proteogenic amino acids were synthesized in 20–98% isolated yields through the Zincke reaction in the presence of triethylamine. Their physicochemical properties including spectroscopy and redox potential were characterized. Preliminary activity screening results showed that a few reduced analogs were effective as cofactors for a mutant cytochrome P450 enzyme to facilitate fatty acid hydroxylation.

Проникновение противоопухолевых нуклеотид-актиномициновых нанокомплексов в тимоциты

С помощью спектрофотометрии, спектрофлуориметрии, ИК-спектроскопии и квазитемнопольной и флуоресцентной микроскопии изучены условия проникновения гетероциклического противоопухолевого антибиотика актиномицина Д (АМД) и его флуоресцирующего производного 7-амино-актиномицина Д (7ААМД) в Т-лимфоциты (тимоциты) из тимуса молодых крыс. Выявлено, что сами по себе АМД и 7ААМД плохо проникают в тимоциты. Следовательно, при использовании в качестве лекарственных средств они не подавляют клеточный иммунитет, необходимый для защиты организма от онкологии. Проникновение АМД и 7ААМД в тимоциты усиливается при повышенной концентрации антибиотика и увеличении длительности инкубации клеток при 37°С. При добавлении НАД (никотинамидадениндинуклеотида), АМФ (аденозинмонофосфата), ГМФ (гуанозинмонофосфата) и других нуклеотидных аналогов, способных образовывать нанокомплексы с антибиотиком, вхождение АМД и 7ААМД в тимоциты заметно возрастает. Поэтому лечение онкологических заболеваний актиномициновыми антибиотиками нельзя проводить на фоне высоких концентраций указанных веществ. С другой стороны, полученные результаты по усиленному вхождению антибиотика в присутствии нуклеотидных аналогов означают, что в их присутствии терапевтическую концентрацию антибиотика можно снизить. Эти данные могут быть использованы при лечении лимфом, лейкозов и других онкологических заболеваний. В этом случае применение НАД и других нуклеотидных аналогов будет полезным. Процент погибших клеток, определяемый по окрашиванию трипановым синим, особенно сильно возрастает при применении НАД.

Engineering d-Lactate Dehydrogenase to Favor an Non-natural Cofactor Nicotinamide Cytosine Dinucleotide.

Synthetic nicotinamide adenine dinucleotide (NAD) analogues are of great scientific and biotechnological interest. One such analogue, nicotinamide cytosine dinucleotide (NCD), has been successfully applied to creating bioorthogonal redox systems. Yet, only a few redox enzymes have been devised to favor NCD. We have engineered Lactobacillus helveticus-derived NAD-dependent d-lactate dehydrogenase (LhDLDH) to favor NCD by semirational design. Sequence alignment and structural analysis revealed that amino acid residues I177 and N213 form a "gate" guarding the NAD adenine moiety binding cavity. Saturated mutagenesis libraries were constructed by using the mutant LhDLDH-V152R as the parental sequence. Mutants were obtained with good catalytic efficiency, and NCD preference increased by up to 940-fold. Experiments showed that Escherichia coli cells expressing mutants with higher NCD preference afforded much less d-lactate, thus suggesting the potential to construct NCD-mediated orthogonal metabolism.

NAD Analogs in Aid of Chemical Biology and Medicinal Chemistry.

Nicotinamide adenine dinucleotide (NAD) serves as an essential redox co-factor and mediator of multiple biological processes. Besides its well-established role in electron transfer reactions, NAD serves as a substrate for other biotransformations, which, at the molecular level, can be classified as protein post-translational modifications (protein deacylation, mono-, and polyADP-ribosylation) and formation of signaling molecules (e.g., cyclic ADP ribose). These biochemical reactions control many crucial biological processes, such as cellular signaling and recognition, DNA repair and epigenetic modifications, stress response, immune response, aging and senescence, and many others. However, the links between the biological effects and underlying molecular processes are often poorly understood. Moreover, NAD has recently been found to tag the 5′-ends of some cellular RNAs, but the function of these NAD-capped RNAs remains largely unrevealed. Synthetic NAD analogs are invaluable molecular tools to detect, monitor, structurally investigate, and modulate activity of NAD-related enzymes and biological processes in order to aid their deeper understanding. Here, we review the recent advances in the design and development of NAD analogs as probes for various cellular NAD-related enzymes, enzymatic inhibitors with anticancer or antimicrobial therapeutic potential, and other NAD-related chemical biology tools. We focus on research papers published within the last 10 years.

Metabolism and biochemical properties of nicotinamide adenine dinucleotide (NAD) analogs, nicotinamide guanine dinucleotide (NGD) and nicotinamide hypoxanthine dinucleotide (NHD)

Nicotinamide adenine dinucleotide (NAD) is an important coenzyme that regulates various metabolic pathways, including glycolysis, β-oxidation, and oxidative phosphorylation. Additionally, NAD serves as a substrate for poly(ADP-ribose) polymerase (PARP), sirtuin, and NAD glycohydrolase, and it regulates DNA repair, gene expression, energy metabolism, and stress responses. Many studies have demonstrated that NAD metabolism is deeply involved in aging and aging-related diseases. Previously, we demonstrated that nicotinamide guanine dinucleotide (NGD) and nicotinamide hypoxanthine dinucleotide (NHD), which are analogs of NAD, are significantly increased in Nmnat3-overexpressing mice. However, there is insufficient knowledge about NGD and NHD in vivo. In the present study, we aimed to investigate the metabolism and biochemical properties of these NAD analogs. We demonstrated that endogenous NGD and NHD were found in various murine tissues, and their synthesis and degradation partially rely on Nmnat3 and CD38. We have also shown that NGD and NHD serve as coenzymes for alcohol dehydrogenase (ADH) in vitro, although their affinity is much lower than that of NAD. On the other hand, NGD and NHD cannot be used as substrates for SIRT1, SIRT3, and PARP1. These results reveal the basic metabolism of NGD and NHD and also highlight their biological function as coenzymes.

Escherichia coli Strain Designed for Characterizing in Vivo Functions of Nicotinamide Adenine Dinucleotide Analogues.

An Escherichia coli strain was constructed for the efficient import of nicotinamide adenine dinucleotide (NAD) analogues into cells by limiting extracellular degradation while expressing an efficient NAD importer. In vivo functions of three NAD analogues were characterized. Nicotinamide hypoxanthine dinucleotide was identified as an inhibitor of NAD synthesis. Nicotinamide cytosine dinucleotide had excellent biocompatibility and was used for characterizing a growth-dependent degradation of in vivo nicotinamide cofactors.

18F]-SuPAR: A Radiofluorinated Probe for Noninvasive Imaging of DNA Damage-Dependent Poly(ADP-ribose) Polymerase Activity.

Poly(ADP ribose) polymerase (PARP) enzymes generate poly(ADP ribose) post-translational modifications on target proteins for an array of functions centering on DNA and cell stress. PARP isoforms 1 and 2 are critically charged with the surveillance of DNA integrity and are the first line guardians of the genome against DNA breaks. Here we present a novel probe ([18F]-SuPAR) for noninvasive imaging of PARP-1/2 activity using positron emission tomography (PET). [18F]-SuPAR is a radiofluorinated nicotinamide adenine dinucleotide (NAD) analog that can be recognized by PARP-1/2 and incorporated into the long branched polymers of poly(ADP ribose) (PAR). The measurement of PARP-1/2 activity was supported by a reduction of radiotracer uptake in vivo following PARP-1/2 inhibition with talazoparib treatment, a potent PARP inhibitor recently approved by FDA for treatment of breast cancer, as well as ex vivo colocalization of radiotracer analog and poly(ADP ribose). With [18F]-SuPAR, we were able to map the dose- and time-dependent activation of PARP-1/2 following radiation therapy in breast and cervical cancer xenograft mouse models. Tumor response to therapy was determined by [18F]-SuPAR PET within 8 h of administration of a single dose of radiation equivalent to one round of stereotactic ablative radiotherapy.

Overexpression of Nmnat3 efficiently increases NAD and NGD levels and ameliorates age-associated insulin resistance.

SummaryNicotinamide adenine dinucleotide (NAD) is an important cofactor that regulates various biological processes, including metabolism and gene expression. As a coenzyme, NAD controls mitochondrial respiration through enzymes of the tricarboxylic acid (TCA) cycle, β‐oxidation, and oxidative phosphorylation and also serves as a substrate for posttranslational protein modifications, such as deacetylation and ADP‐ribosylation by sirtuins and poly(ADP‐ribose) polymerase (PARP), respectively. Many studies have demonstrated that NAD levels decrease with aging and that these declines cause various aging‐associated diseases. In contrast, activation of NAD metabolism prevents declines in NAD levels during aging. In particular, dietary supplementation with NAD precursors has been associated with protection against age‐associated insulin resistance. However, it remains unclear which NAD synthesis pathway is important and/or efficient at increasing NAD levels in vivo. In this study, Nmnat3 overexpression in mice efficiently increased NAD levels in various tissues and prevented aging‐related declines in NAD levels. We also demonstrated that Nmnat3‐overexpressing (Nmnat3 Tg) mice were protected against diet‐induced and aging‐associated insulin resistance. Moreover, in skeletal muscles of Nmnat3 Tg mice, TCA cycle activity was significantly enhanced, and the energy source for oxidative phosphorylation was shifted toward fatty acid oxidation. Furthermore, reactive oxygen species (ROS) generation was significantly suppressed in aged Nmnat3 Tg mice. Interestingly, we also found that concentrations of the NAD analog nicotinamide guanine dinucleotide (NGD) were dramatically increased in Nmnat3 Tg mice. These results suggest that Nmnat3 overexpression improves metabolic health and that Nmnat3 is an attractive therapeutic target for metabolic disorders that are caused by aging.

Identification of the Nicotinamide Salvage Pathway as a New Toxification Route for Antimetabolites

Interest in the modulation of nicotinamide adenine dinucleotide (NAD) metabolome is gaining great momentum because of its therapeutic potential indifferent human disorders. Suppression of nicotinamide salvage by nicotinamide phosphoribosyl transferase (NAMPT) inhibitors, however, gave inconclusive results in neoplastic patients because several metabolic routes circumvent the enzymatic block converging directly on nicotinamide mononucleotide adenylyl transferases (NMNATs) for NAD synthesis. Unfortunately, NMNAT inhibitors have not been identified. Here, we report the identification of Vacor as a substrate metabolized by theconsecutive action of NAMPT and NMNAT2 into the NAD analog Vacor adenine dinucleotide (VAD).This leads to inhibition of both enzymes, as wellas NAD-dependent dehydrogenases, thereby causing unprecedented rapid NAD depletion, glycolytic block, energy failure, and necrotic death of NMNAT2-proficient cancer cells. Conversely, lack of NMNAT2 expression confers complete resistance to Vacor. Remarkably, Vacor prompts VAD formation and growth suppression in NMNAT2-positive neuroblastoma and melanoma xenografts. Our data show the first evidence of harnessing the entire nicotinamide salvage pathway for antimetabolic strategies.

Using Clickable NAD+ Analogs to Label Substrate Proteins of PARPs.

ADP-ribosylation has been well known as an important posttranslational modification, which is catalyzed by a family of enzymes called poly(ADP-ribose) polymerases (PARPs). PARPs transfer of a single or multiple adenine diphosphate ribose (ADP-ribose) units from nicotinamide adenine dinucleotide (NAD+) to specific amino acids on substrate proteins. Through mono- or poly-ADP-ribosylation enzymatic activities, PARPs regulate various biological processes, including DNA damage repair, chromatin remodeling, transcriptional regulation, RNA processing and metabolism. Notably, PARP inhibitors are in clinical trials to treat human diseases, in particular cancer. To further investigate the biological function of PARPs, and to achieve better therapeutic effect of PARP inhibitors, it is important to identify the physiological substrates of PARPs. Here we describe a protocol to use clickable analog of nicotinamide adenine dinucleotide (NAD+) that can be applied for the detection, affinity purification and identification of substrate proteins of PARPs.

Effect of Site-Directed Mutagenesis in Coenzyme-Binding Domain of Malic Enzyme on Coenzyme Activities for Nicotinamide Adenine Dinucleotide Analogs

Effect of Site-Directed Mutagenesis in Coenzyme-Binding Domain of Malic Enzyme on Coenzyme Activities for Nicotinamide Adenine Dinucleotide Analogs

From ribavirin to NAD analogues and back to ribavirin in search for anticancer agents

Abstract Ribavirin, a broad-spectrum antiviral agent is used in the clinic alone or in combination with other antivirals and/or interferons. Numerous structural analogues of ribavirin have been developed, among them tiazofurin, which is inactive against viruses but is a potent anticancer drug. Tiazofurin was found to inhibit nicotinamide adenine dinucleotide (NAD)-dependent inosine monophosphate dehydrogenase (IMPDH) after metabolic conversion into tiazofurin adenine dinucleotide (TAD), which binds well but could not serve as IMPDH cofactor. TAD showed high selectivity against human IMPDH vs. other cellular dehydrogenases. Mycophenolic acid (MPA) was even more specific, binding at the cofactor-binding domain of IMPDH. Ribavirin adenine dinucleotide, however, did not show any significant inhibition at the enzymatic level. We synthesized numerous NAD analogues in which natural nicotinamide riboside was replaced by tiazofurin, MPA moiety, or benzamide riboside, and the adenosine moiety as well as the pyrophosphate linker were broadly modified. Some of these compounds were found to be low nanomolar inhibitors of the enzyme and sub-micromolar inhibitors of cancer cell line proliferation. The best were as potent as tyrosine kinase inhibitor gleevec heralded as a ‘magic bullet’ against chronic myelogenous leukemia. In recent years, ribavirin was rediscovered as a potential anticancer agent against number of tumors including leukemia. It was clearly established that its antitumor activity is related to the inhibition of an oncogene, the eukaryotic translation initiation factor (eIF4E).

Identifying Direct Protein Targets of Poly-ADP-Ribose Polymerases (PARPs) Using Engineered PARP Variants-Orthogonal Nicotinamide Adenine Dinucleotide (NAD+) Analog Pairs.

Poly-ADP-ribose polymerases (PARPs) comprise a family of 17 distinct enzymes that catalyze the transfer of ADP-ribose from nicotinamide adenine dinucleotide (NAD+) to acceptor sites on protein targets. PARPs have been implicated in a number of essential signaling pathways regulating both normal cell function and pathophysiology. To understand the physiological role of each PARP family member in the cell we need to identify the direct targets for each unique PARP in a cellular context. PARP-family member-specific target identification is challenging because of their shared catalytic mechanism and functional redundancy. To address this challenge, we have engineered a PARP variant that efficiently uses an orthogonal NAD+ analog, an analog that endogenous PARPs cannot use, as a substrate for ADP-ribosylation. The protocols in this unit describe a general procedure for using engineered PARP variants-orthogonal NAD+ analog pairs for labeling and identifying the direct targets of the poly-subfamily of PARPs (PARPs 1-3, 5, and 6).

Role of hydrogen-bonding and photoinduced electron transfer (PET) on the interaction of resorcinol based acridinedione dyes with Bovine Serum Albumin (BSA) in water

Resorcinol based acridinedione (ADDR) dyes are a class of laser dyes and have structural similarity with purine derivatives, nicotinamide adenine dinucleotide (NADH) analogs. These dyes are classified into photoinduced electron transfer (PET) and non-photoinduced electron transfer dyes, and the photophysical properties of family of these dyes exhibiting PET behavior are entirely different from that of non-PET dyes. The PET process in ADDR dyes is governed by the solvent polarity such that an ADDR dye exhibits PET process through space in an aprotic solvent like acetonitrile and does not exhibit the same in protic solvents like water and methanol. A comparison on the fluorescence emission, lifetime and nature of interaction of various ADDR dyes with a large globular protein like Bovine Serum Albumin (BSA) was carried out in aqueous solution. The interaction of PET based ADDR dyes with BSA in water is found to be largely hydrophobic, but hydrogen-bonding interaction of BSA with dye molecule influences the fluorescence emission of the dye and shifts the emission towards red region. Fluorescence spectral studies reveal that the excited state properties of PET based ADDR dyes are largely influenced by the addition of BSA. The microenvironment around the dye results in significant change in the fluorescence lifetime and emission. Fluorescence enhancement with a red shift in the emission results after the addition of BSA to ADDR dyes containing free amino hydrogen in the 10th position of basic acridinedione dye. The amino hydrogen (N–H) in the 10th position of ADDR dye is replaced by methyl group (N–CH3), a significant decrease in the fluorescence intensity with no apparent shift in the emission maximum was observed after the addition of BSA. The nature of interaction between ADDR dyes with BSA is hydrogen-bonding and the dye remains unbound even at the highest concentration of BSA. Circular Dichroism (CD) studies show that the addition of dye to BSA results in a decrease in the alpha helical content of the protein. The shape and the pattern of CD bands after the addition of ADDR dye to BSA remain largely unaltered.

Design, synthesis and SAR studies of NAD analogues as potent inhibitors towards CD38 NADase.

Nicotinamide adenine dinucleotide (NAD), one of the most important coenzymes in the cells, is a substrate of the signaling enzyme CD38, by which NAD is converted to a second messenger, cyclic ADP-ribose, which releases calcium from intracellular calcium stores. Starting with 2′-deoxy-2′-fluoroarabinosyl-β-nicotinamide adenine dinucleotide (ara-F NAD), a series of NAD analogues were synthesized and their activities to inhibit CD38 NAD glycohydrolase (NADase) were evaluated. The adenosine-modified analogues showed potent inhibitory activities, among which 2′-deoxy-2′-fluoroarabinosyl-β-nicotinamideguanine dinucleotide (ara-F NGD) was the most effective one. The structure-activity relationship of NAD analogues was also discussed.

Synthesis and crystal structures of 2-methyl-4-aryl-5-oxo-5H-indeno [1,2-b] pyridine carboxylate derivatives

Abstract Background Hantzsch 1,4-dihydropyridines (Hantzsch1,4-DHP) have been extensively utilized as the analogs of nicotinamide adenine dinucleotide (NADH) coenzyme to study the mechanism and various redox processes. During the redox processes 1,4-DHP systems undergo transformation into the corresponding pyridine derivatives through oxidation. Consequently, the interest in this aromatization reaction, investigation of a wide range of 1, 4-DHPs continues to attract the attention of researchers. Herein, we report the preparation of pyridine derivatives and the crystal structures determined by X-ray crystallographic methods. Results The crystal structures and conformational studies of two organic compounds, namely ethyl 2-methyl-4-phenyl-5-oxo-5H-indeno [1,2-b] pyridine-3-carboxylate (I) and ethyl 2-methyl-4-(4 chlorophenyl)-5-oxo-5H-indeno [1,2-b] pyridine-3-carboxylate (II) are reported. The terminal ethyl group of the compound I is disordered over two positions with the refined occupancies of 0.645 & 0.355 and C8 one dimensional zig-zag chain running along 101 direction through C-H…O type of intermolecular interactions. In the compound II, C-H…O interactions connect the molecules to form an R2 2 (16) dimer running along 011 direction. Conclusion The crystal structures ethyl 2-methyl-4-phenyl-5-oxo-5H-indeno [1,2-b] pyridine-3-carboxylate and ethyl 2-methyl-4-(4 chlorophenyl)-5-oxo-5H-indeno [1,2-b] pyridine-3-carboxylate have been investigated in detail. The terminal ethyl group of compound I is disordered. In compound II, the substitution of Cl atom in the phenyl ring alters the configuration of carboxylate group with respect to the pyridine indane ring.