Novel 2-[(benzylamino)methyl]pyrrolidine-3,4-diol derivatives as α-mannosidase inhibitors and with antitumor activities against hematological and solid malignancies

Application of the N-Dibenzyl Protective Group in the Preparation of β-Lactam Pseudopeptides

Despite the great importance of β-lactam antibiotics, there is still a limited number of synthetic approaches for the formation of β-lactam⁻containing dipeptides. In this study, we report upon the stereoselective preparation of β-lactam⁻containing pseudopeptides, where different reaction conditions and NH₂ protective groups were tested to obtain compounds that contain 3-amino-azetidin-2-one. We demonstrate that the protective group is essential for the outcome of the reaction. Successful implementation of dibenzyl-protected serine-containing dipeptides through the Mitsunobu reaction can provide the desired products at high yields and stereoselectivity.

MAN1B1 is associated with poor prognosis and modulates proliferation and apoptosis in bladder cancer

Bladder cancer (BC) has been regarded as the most common malignancy of the urinary system worldwide. With lack of investigations for molecular pathogenesis underlying that develop BC, the therapeutic efficacy of several therapeutic approaches existing is still unsatisfactory. Here, our study aimed to explore the potentially biological function of MAN1B1 on BC. In this study, MAN1B1 expression level in BC tissues and normal tissues was analyzed based on The Cancer Genome Atlas (TCGA) data and correlation between its expression and prognosis was determined using Kaplan-Meier analysis. Knockout of MAN1B1 was performed using silencing RNA and the efficacy of MAN1B1 knockout was identified using quantitative reverse transcription polymerase chain reaction (qRT-PCR) analysis. The BC cells proliferation was assessed by Cell Counting Kit-8 (CCK8) assay, and then the cells apoptosis was detected by Annexin V-fluorescein isothiocyanate (Annexin V-FITC)/propidium iodide (PI) staining and flow cytometry following MAN1B1 knocked down by small interfering RNA. Protein kinase B (AKT) signaling was evaluated by detecting related markers, namely AKT, p-AKT, 4E-BP-1 and Bax using western blot assay. As a result, the MAN1B1 expression was higher in BC tissues than those in normal tissues, besides, its overexpression was associated with poor prognosis. Moreover, MAN1B1 reduction by silencing RNA approach resulted in BC cells proliferation suppression and BC cells apoptosis promotion. Finally, AKT signaling activity was inhibited by MAN1B1 silencing. Taken together, these results unraveled that MAN1B1 may act on an oncogenic action in BC, which improved the likelihood of MAN1B1 taking on a promising prognostic biomarker and a potential target for treating BC.

1-Allyl-3′-phenyl-6′H-spiro[indoline-3,4′-isoxazolo[4′,5′:5,6]pyrido[2,3-d]pyrimidine]-2,5′,7′(8′H,9′H)-trione dimethyl sulfoxide monosolvate

In the title solvated compound, C24H17N5O4·C2H6OS, the solvent molecule, dimethyl sulfoxide, is linked to the title molecule by an N—H...O hydrogen bond. The pyridine ring adopts a twist-boat conformation. The isoxazole ring is inclined to the indoline ring system, the pyrimidine ring, and the phenyl ring by 82.31 (7), 10.41 (8) and 53.77 (10)°, respectively. There is an intramolecular C—H...π interaction present involving the phenyl ring and the indoline ring system. In the crystal, molecules are connected by two pairs of N—H...O hydrogen bonds, forming chains along theb-axis direction, and enclosingR22(8) andR22(14) ring motifs. The chains are linked by C—H...O and C—H...N hydrogen bonds and offset π–π interactions, between the pyrimidine and isoxazole rings of inversion-related molecules [centroid–centroid distance = 3.7140 (9) Å], forming a three-dimensional structure.

3-Hydroxypyrrolidine and (3,4)-dihydroxypyrrolidine derivatives: inhibition of rat intestinal α-glucosidase

Thirteen pyrrolidine-based iminosugar derivatives have been synthesized and evaluated for inhibition of α-glucosidase from rat intestine. The compounds studied were the non-hydroxy, mono-hydroxy and dihydroxypyrrolidines. All the compounds were N-benzylated apart from one. Four of the compounds had a carbonyl group in the 2,5-position of the pyrrolidine ring. The most promising iminosugar was the trans-3,4-dihydroxypyrrolidine 5 giving an IC50 of 2.97±0.046 and a KI of 1.18 mM. Kinetic studies showed that the inhibition was of the mixed type, but predominantly competitive for all the compounds tested. Toxicological assay results showed that the compounds have low toxicity. Docking studies showed that all the compounds occupy the same region as the DNJ inhibitor on the enzyme binding site with the most active compounds establishing similar interactions with key residues. Our studies suggest that a rotation of ∼90° of some compounds inside the binding pocket is responsible for the complete loss of inhibitory activity. Despite the fact that activity was found only in the mM range, these compounds have served as simple molecular tools for probing the structural features of the enzyme, so that inhibition can be improved in further studies.

Deoxysugars as antituberculars and alpha-mannosidase inhibitors

A promising modified sugar molecule was identified which was active against multidrug-resistant (MDR) strains of Mycobacterium tuberculosis, suggesting involvement of a new target. The compound was demonstrated to be bactericidal, inhibited the growth of M. tuberculosis in mice, and targeted alpha-mannosidase as a competitive inhibitor with a Ki value of 353.9 μM.

(3aR,8bR)-3a,8b-Dihy-droxy-1-(4-meth-oxy-phen-yl)-2-methyl-sulfan-yl-3-nitro-1,8b-di-hydro-indeno-[1,2-b]pyrrol-4(3aH)-one

In the title compound, C19H16N2O6S, the pyrrolidine ring adopts a twisted conformation with puckering parameters q 2 = 0.088 (3) Å and Φ2 = 61.5 (14)°. The cyclo-pentane ring adopts a twisted conformation with puckering parameters q 2 = 0.099 (2) Å and Φ2 = 242.8 (14)°. A weak intra-molecular O-H⋯O inter-action occurs. In the crystal, pairs of C-H⋯O inter-actions generate dimers with graph-set motif R 2 (2)(24) and they are interconnected by pairs of O-H⋯O hydrogen bonds, which link the mol-ecules into inversion dimers with graph-set motif R 2 (2)(10).

Antinociceptive activity of a synthetic oxopyrrolidine-based compound, ASH21374, and determination of its possible mechanisms

This study was carried out to determine the antinociceptive activity of a novel synthetic oxopyrrolidine-based compound, (2R,3R,4S)-ethyl 4-hydroxy-1,2-dimethyl-5-oxopyrrolidine-3-carboxylate (ASH21374), and to elucidate the involvement of the opioid, vanilloid, glutamate, and nitric oxide - cyclic guanosine monophosphate (NO/cGMP) systems in modulating the observed antinociception. ASH21374, in the doses of 2, 10, and 100 mg/kg body mass, was administered orally to mice 60 mins prior to exposure to various antinociceptive assays. From the results obtained, ASH21374 exhibited significant (P < 0.05) antinociceptive activity in the abdominal constriction, hot-plate, and formalin tests that was comparable with 100 mg/kg acetylsalicylic acid or 5 mg/kg morphine, respectively. ASH21374 also attenuated capsaicin- and glutamate-induced paw licking. Pre-treatment with 5 mg/kg naloxone significantly (P < 0.05) inhibited the activity in all assays, while pretreatment with 10 mg/kg β-funaltraxamine, 1 mg/kg naltrindole, or 1 mg/kg nor-binaltorphimine significantly (P < 0.05) reversed the activity in the abdominal constriction test. l-Arginine, N(G)-nitro-l-arginine methyl esters (l-NAME), methylene blue, and their combinations, failed to inhibit the ASH21374 antinociceptive activity. In conclusion, ASH21374 demonstrated antinociceptive activities on the peripheral and central nervous systems, mediated through the activation of opioid receptors, inhibition of the glutamatergic system, and attenuation of vanilloid-mediated nociceptive transmission. Further studies have been planned to determine the pharmacological potential of ASH21374.

3′-[Hydroxy(4-oxo-4H-chromen-3-yl)methyl]-2-oxospiro[indoline-3,2′-pyrrolidine]-3′-carbonitrile

In the title compound, C₂₃H₁₉N₃O₄, the pyran ring adopts a half-chair conformation, while the pyrrolidine (with a C atom as the flap atom) and the five-membered ring in the indoline (with a C atom as the flap atom) ring system adopt slight envelope conformations. The pyrrolidine ring makes dihedral angles of 83.3 (1) and 60.4 (1)° with the mean plane through all non-H atoms of the indoline and chromene ring systems, respectively. In the crystal, mol­ecules are connected by two unique N—H⋯O and O—H⋯O hydrogen-bonding inter­actions, which form centrosymmetric patterns described by graph-set motifs R₂²(18) and R₂²(14). These two motifs combine to form a hydrogen-bonded chain which propagates in the a-axis direction. The crystal structure is also stablized by C—H⋯O inter­actions and by aromatic π–π stacking inter­actions between the pyran and benzene rings of neighbouring mol­ecules [centroid–centroid distance = 3.755 (1) Å and slippage = 1.371 (2) Å].

Anti-cancer activity of 5-O-alkyl 1,4-imino-1,4-dideoxyribitols

New derivatives of 1,4-dideoxy-1,4-imino-D-ribitol have been prepared and evaluated for their cytotoxicity on solid and haematological malignancies. 1,4-Dideoxy-5-O-[(9Z)-octadec-9-en-1-yl]-1,4-imino-D-ribitol (13, IC(50) ∼2 μM) and its C(18)-analogues (IC(50) <10 μM) are cytotoxic toward SKBR3 (breast cancer) cells. 13 also inhibits (IC(50) ∼8 μM) growth of JURKAT cells.

Asymmetric Strecker synthesis of α-arylglycines

A practically simple three-component Strecker reaction for the asymmetric synthesis of enantiopure α-arylglycines has been developed. Addition of a range of aryl-aldehydes to a solution of sodium cyanide and (S)-1-(4-methoxyphenyl)ethylamine affords highly crystalline (S,S)-α-aminonitriles that are easily obtained in diastereomerically pure form. Heating the resultant (S,S)-α-aminonitriles in 6 M aqueous HCl at reflux resulted in cleavage of their chiral auxiliary fragments and concomitant hydrolysis of their nitrile groups to afford enantiopure (S)-α-arylglycines. The enantiopurities of these (S)-α-arylglycines were determined via derivatization of their corresponding methyl esters with 2-formylphenylboronic acid and (S)-BINOL, followed by (1)H NMR spectroscopic analysis of the resultant mixtures of diastereomeric iminoboronate esters.

1'-Methyl-4'-(1-naphth-yl)-1'',2'',3'',4''-tetra-hydro-indane-2-spiro-2'-pyrrolidine-3'-spiro-2''-naphthalene-1,3,1''-trione

In the title compound, C₃₂H₂₅NO₃, the pyrrolidine ring adopts an envelope conformation, whereas the cyclo­hexa­none ring in the tetra­hydro­naphthalene fused-ring system adopts a half-chair conformation. The indanedione unit is oriented at an angle of 58.9 (1)° with respect to the naphthyl ring system. Three intra­molecular C—H⋯O close contacts and an intra­molecular C—H⋯π inter­action are observed. In the crystal, mol­ecules associate via C—H⋯O hydrogen bonds, forming a helical chain with a C(10) motif along the b axis.

Methyl 3-[(1H-benzimidazol-1-yl)methyl]-1-methyl-4-(4-methylphenyl)-2′-oxopyrrolidine-2-spiro-3′-1-benzimidazole-3-carboxylate

In the title compound, C₂₉H₂₈N₄O₃, the pyrrolidine ring adopts a twist conformation whereas the oxindole and benzimidazole residues are approximately planar with maximum deviations of 0.159 (1) and 0.011 (1) Å, respectively. The oxindole residue is almost perpendicular to the benzimidazole residue, making a dihedral angle of 89.2 (1)°. The methyl-substituted benzene ring is oriented at angles of 47.7 (1) and 71.0 (1)°, respectively, with respect to the oxindole and benzimidazole residues. An intra­molecular C—H⋯O hydrogen bond is observed. In the crystal, mol­ecules associate via N—H⋯N hydrogen bonds, forming R₂²(9) dimers.