MORONIC ACID: A REVIEW

Moronic acid is a pentacyclic triterpenoid made up of olean-18-ene with an oxo group at position 3 and a carboxy group at position 28. It's made from an oleanane hydride. A few investigations have demonstrated that Moronic acid a wide scope of pharmacological effects such as Antidiabetic activity, Anti-AIDS agents, Chemotherapeutic agents, Virus lytic, Anti-HIV, Cytotoxic activity, Anti-herpes, Antimicrobial activity, Ribosome-loaded mRNAs.

Structural and Binding Effects of Chemical Modifications on Thrombin Binding Aptamer (TBA)

The thrombin binding aptamer (TBA) is a promising nucleic acid-based anticoagulant. We studied the effects of chemical modifications, such as dendrimer Trebler and NHS carboxy group, on TBA with respect to its structures and thrombin binding affinity. The two dendrimer modifications were incorporated into the TBA at the 5′ end and the NHS carboxy group was added into the thymine residues in the thrombin binding site of the TBA G-quadruplex (at T4, T13 and both T4/T13) using solid phase oligonucleotide synthesis. Circular dichroism (CD) spectroscopy confirmed that all of these modified TBA variants fold into a stable G-quadruplex. The binding affinity of TBA variants with thrombin was measured by surface plasmon resonance (SPR). The binding patterns and equilibrium dissociation constants (KD) of the modified TBAs are very similar to that of the native TBA. Molecular dynamics simulations studies indicate that the additional interactions or stability enhancement introduced by the modifications are minimized either by the disruption of TBA–thrombin interactions or destabilization elsewhere in the aptamer, providing a rational explanation for our experimental data. Overall, this study identifies potential positions on the TBA that can be modified without adversely affecting its structure and thrombin binding preference, which could be useful in the design and development of more functional TBA analogues.

Synthesis of Borylated Hydrazino Acid Derivatives

Abstractα-Boryl-α-hydrazinoacetic acid is a highly functionalized boron-containing building block that can be easily accessed from readily available α-borylacetaldehyde. The hydrazine motif can be converted into a variety of α-borylated azoles and diazines in a straightforward protocol. Furthermore, the carboxy group can be derivatized to afford novel organoboron compounds that should find applications in various cross-coupling transformations.

Benzylmalonyl-CoA dehydrogenase, an enzyme involved in bacterial auxin degradation

A novel acyl-CoA dehydrogenase involved in degradation of the auxin indoleacetate by Aromatoleum aromaticum was identified as a decarboxylating benzylmalonyl-CoA dehydrogenase (IaaF). It is encoded within the iaa operon coding for enzymes of indoleacetate catabolism. Using enzymatically produced benzylmalonyl-CoA, the reaction was characterized as simultaneous oxidation and decarboxylation of benzylmalonyl-CoA to cinnamoyl-CoA and CO2. Oxygen served as electron acceptor and was reduced to H2O2, whereas electron transfer flavoprotein or artificial dyes serving as electron acceptors for other acyl-CoA dehydrogenases were not used. The enzyme is homotetrameric, contains an FAD cofactor and is enantiospecific in benzylmalonyl-CoA turnover. It shows high catalytic efficiency and strong substrate inhibition with benzylmalonyl-CoA, but otherwise accepts only a few medium-chain alkylmalonyl-CoA compounds as alternative substrates with low activities. Its reactivity of oxidizing 2-carboxyacyl-CoA with simultaneous decarboxylation is unprecedented and indicates a modified reaction mechanism for acyl-CoA dehydrogenases, where elimination of the 2-carboxy group replaces proton abstraction from C2.

Rhodium-catalyzed sequential B(3)−, B(4)−, and B(5)-trifunctionalization of o-carboranes with three different substituents

A rhodium-catalyzed one-pot trifunctionalization of o-carboranes with three different substituents via a carboxy group directed sequential B(5)-alkenylation, B(4)-alkyne annulation and B(3)-acyloxylation has been developed for the first time, leading to...

Iodocyclisation of Electronically Resistant Alkynes: Synthesis of 2-Carboxy (and sulfoxy)-3-iodobenzo[b]thiophenes

The iodocyclisation of alkynes bearing tethered nucleophiles is a highly effective method for the construction and diversification of heterocycles. A key limitation to this methodology is the 5-endo-dig iodocyclisation of alkynes that have an unfavourable electronic bias for electrophilic cyclisation. These tend to direct electrophilic attack of the iodonium atom to the wrong carbon for cyclisation, thus favouring competing addition reactions. Using our previously determined reaction conditions for the 5-endo-dig iodocyclisations of electronically resistant alkynes, we have achieved efficient synthetic access to 2-carboxy (and sulfoxy)-3-iodobenzo[b]thiophenes. The corresponding benzo[b]furans and indoles were not accessible under these conditions. This difference may arise due to the availability of a radical mechanism in the case of iodobenzo[b]thiophenes. The 2-carboxy functionality of the iodocyclised products can be further employed in iterative alkyne-coupling iodocyclisation reactions, where the carboxy group or an imine (Schiff base) partakes in a second iodocyclisation to generate a lactone or pyridine ring.

Crystal structure and Hirshfeld surface analysis of a third polymorph of 2,6-dimethoxybenzoic acid

A third crystalline form of the title compound, C9H10O4, crystallizing in the centrosymmetric monoclinic space group P21/c, has been identified during screening for co-crystals. The asymmetric unit comprises a non-planar independent molecule with a synplanar conformation of the OH group. The sterically bulky o-methoxy substituents force the carboxy group to be twisted away from the plane of the benzene ring by 74.10 (6)°. The carboxy group exhibits the acidic H atom disordered over two sites between two O atoms. A similar situation has been found for the second tetragonal polymorph reported [Portalone (2011). Acta Cryst. E67, o3394–o3395], in which molecules with the OH group in a synplanar conformation form dimeric units via strong O—H...O hydrogen bonds. In contrast, in the first orthorhombic form reported [Swaminathan et al. (1976). Acta Cryst. B32, 1897–1900; Bryan & White (1982). Acta Cryst. B38, 1014–1016; Portalone (2009). Acta Cryst. E65, o327–o328], the molecular components do not form conventional dimeric units, as an antiplanar conformation adopted by the OH group favors the association of molecules in chains stabilized by linear O—H...O hydrogen bonds.