Asymmetric Synthesis of 2-Arylethylamines: A Metal-Free Review of the New Millennium.

2-Arylethylamines are presented in several natural bioactive compounds, as well as in nitrogen-containing drugs. Their ability to surpass the blood-brain barrier makes this family of compounds of especial interest in medicinal chemistry. Asymmetric methodologies towards the synthesis of 2-arylethylamine motives are of great interest due to the challenges they may present.

Insights into podophyllotoxin lactone features: New cyclolignans as potential dual tubulin-topoisomerase II inhibitors.

Chemomodulation of natural cyclolignans as podophyllotoxin has been a successful approach to obtain semisynthetic bioactive derivates. One example of this approach is the FDA-approved drug etoposide for solid and hematological tumors. It differs from the antimitotic activity of the natural product in its mechanism of action, this drug being a topoisomerase II inhibitor instead of a tubulin antimitotic.

2-Heteroarylethylamines in medicinal chemistry: a review of 2-phenethylamine satellite chemical space.

The concept of bioisostere replacement is of paramount importance in medicinal chemistry, as it can be employed as a rational to expand bioactive chemical space to tackle lead optimization issues like lack of potency, efficacy, and selectivity or pharmacokinetic/dynamic issues. One of the most important building blocks (in the sense of participating in a vast area of chemical space of biological importance) in medicinal chemistry is the 2-phenethyl moiety, a key component of diverse drug-like entities. Although the core 2-phenethylamine structure has been recognized by the drug discovery community, little attention has been given to the various ring-based rescaffolding procedures that can be conducted with this unit.

Crystallization-induced diastereomer transformation assists the diastereoselective synthesis of 4-nitroisoxazolidine scaffolds.

This communication describes a solution to the vexing problem of synthesis of 4-nitroisoxazolidine rings from cyclic nitrones and β-nitrostyrenes. The adduct 2 is quantitatively synthesised from -β-nitrostyrene under mild conditions avoiding purification, while the adduct 4 is obtained at higher temperatures. Furthermore, a Crystallization-Induced Diastereomer Transformation (CIDT) process was used to epimerise the NO bond from 2 to the adduct 3 with total conversion assisted by the -halogen substitution of the aromatic ring without any additives.

Podophyllotoxin: Recent Advances in the Development of Hybridization Strategies to Enhance Its Antitumoral Profile.

Podophyllotoxin is a naturally occurring cyclolignan isolated from rhizomes of sp. In the clinic, it is used mainly as an antiviral; however, its antitumor activity is even more interesting. While podophyllotoxin possesses severe side effects that limit its development as an anticancer agent, nevertheless, it has become a good lead compound for the synthesis of derivatives with fewer side effects and better selectivity.

Halimanes and cancer: -halimic acid as a starting material for the synthesis of antitumor drugs.

The development of new anti-cancer agents is an urgent necessity nowadays, as it is one of the major causes of mortality worldwide. Many drugs currently used are derived from natural products. Halimanes are a class of bicyclic diterpenoids present in various plants and microorganisms.

Mesotherapy with Bicalutamide: A New Treatment for Androgenetic Alopecia.

Bicalutamide is a selective androgen receptor antagonist. To date, it has been used orally with good efficacy results, but not in mesotherapy. In our center, we assessed whether patients undergoing bicalutamide mesotherapy showed positive responses and tolerated the local administration of bicalutamide.

Improving Properties of Podophyllic Aldehyde-Derived Cyclolignans: Design, Synthesis and Evaluation of Novel Lignohydroquinones, Dual-Selective Hybrids against Colorectal Cancer Cells.

New lignohydroquinone conjugates (L-HQs) were designed and synthesized using the hybridization strategy, and evaluated as cytotoxics against several cancer cell lines. The L-HQs were obtained from the natural product podophyllotoxin and some semisynthetic terpenylnaphthohydroquinones, prepared from natural terpenoids. Both entities of the conjugates were connected through different aliphatic or aromatic linkers.

2-Phenethylamines in Medicinal Chemistry: A Review.

A concise review covering updated presence and role of 2-phenethylamines in medicinal chemistry is presented. Open-chain, flexible alicyclic amine derivatives of this motif are enumerated in key therapeutic targets, listing medicinal chemistry hits and appealing screening compounds. Latest reports in discovering new bioactive 2-phenethylamines by research groups are covered too.

Synthesis and Modeling of Ezetimibe Analogues.

Ezetimibe is a well-known drug that lowers blood cholesterol levels by reducing its absorption in the small intestine when joining to Niemann-Pick C1-like protein (NPC1L1). A ligand-based study on ezetimibe analogues is reported, together with one-hit synthesis, highlighted in the study. A convenient asymmetric synthesis of (2,3)--α-()-methylbenzyl-3-methoxycarbonylethyl-4-methoxyphenyl β-lactam is described starting from Baylis-Hillman adducts.

1,3-Cyclohexadien-1-Als: Synthesis, Reactivity and Bioactivities.

In synthetic organic chemistry, there are very useful basic compounds known as building blocks. One of the main reactions wherein they are applied for the synthesis of complex molecules is the Diels-Alder cycloaddition. This reaction is between a diene and a dienophile.

A Novel Cytotoxic Conjugate Derived from the Natural Product Podophyllotoxin as a Direct-Target Protein Dual Inhibitor.

Natural products are the ideal basis for the design of novel efficient molecular entities. Podophyllotoxin, a naturally occurring cyclolignan, is an example of natural product which displays a high versatility from a biological activity point of view. Based on its unique chemical structure, different derivatives have been synthesized presenting the original antitumoral properties associated with the compound, i.

Antibacterial Natural Halimanes: Potential Source of Novel Antibiofilm Agents.

The development of new agents against bacteria is an urgent necessity for human beings. The structured colony of bacterial cells, called the biofilm, is used to defend themselves from biocide attacks. For this reason, it is necessary to know their structures, develop new agents to eliminate them and to develop new procedures that allow an early diagnosis, by using biomarkers.

Multicomponent Domino Reaction in the Asymmetric Synthesis of Cyclopentan[c]pyran Core of Iridoid Natural Products.

The asymmetric synthesis of a compound with the cyclopentan[c]pyran core of iridoid natural products in four steps and 40% overall yield is reported. Our methodology includes a one-pot tandem domino reaction which provides a trisubstituted cyclopentane with five new completely determined stereocenters, which were determined through 2D homo and heteronuclear NMR and n.O.

The Methylene-Cycloalkylacetate (MCA) Scaffold in Terpenyl Compounds with Potential Pharmacological Activities.

Recently, the methylene-cycloakylacetate (MCA) scaffold has been reported as a potential pharmacophore for neurite outgrowth activity. In this work, natural diterpenes that embed MCA fragments are reviewed, as they are major components of : -halimic acid, the prototype for these bioactive compounds. Herein, structures, sources, and activities for the natural diterpenes, as well as their synthetic derivatives of interest, are reviewed.

Organocatalyzed Synthesis of [3.2.1] Bicyclooctanes.

Organocatalysis constitutes one of the main research areas in organic chemistry from the last two decades. This chemistry has been applied to the synthesis of many natural products and structures in a manner that reduces the residues and so the ecological impact. In this review, we consider the work that has been done for the synthesis of bicyclo[3.

Halimane diterpenoids: sources, structures, nomenclature and biological activities.

Covering: 1970 to 2017 Diterpenes with a halimane skeleton constitute a small group of natural products that can be biogenetically considered as being between labdane and clerodane diterpenoids. Some of these compounds show biological activities, such as antitumour, mosquito repellency, germination inhibition and antimicrobial, as well as being biomarkers for tuberculosis. To the best of our knowledge, there are no reviews on these compounds.

New Hybrids Derived from Podophyllic Aldehyde and Diterpenylhydroquinones with Selectivity toward Osteosarcoma Cells.

A new family of molecular hybrids, between cyclolignans related to podophyllic aldehyde and several diterpenylnaphthohydroquinones (DNHQ), was prepared and its biological activity evaluated in several human solid tumor cell lines, which are representative of the most prevalent solid tumors in the Western world. Both cyclolignan and quinone fragments were linked through aliphatic or aromatic spacers. The new hybrid family was evaluated for its cytotoxicity, and it was found that the hybrids were several times more potent against the osteosarcoma cell line MG-63 than against MCF-7 and HT-29 cell lines.

Diastereoselective synthesis of chiral 1,3-cyclohexadienals.

A novel approach to the production of chiral 1,3-cyclohexadienals has been developed. The organocatalysed asymmetric reaction of different β-disubstituted-α,β-unsaturated aldehydes with a chiral α,β-unsaturated aldehyde in the presence of a Jørgensen-Hayashi organocatalyst provides easy and stereocontrolled access to the cyclohexadienal backbone. This method allows for the synthesis of potential photoprotective chiral 1,3-cyclohexadienals and extra extended conjugation compounds in a simple manner.

Marine Alkylpurines: A Promising Group of Bioactive Marine Natural Products.

Marine secondary metabolites with a purine motif in their structure are presented in this review. The alkylpurines are grouped according to the size of the alkyl substituents and their location on the purine ring. Aspects related to the marine source, chemical structure and biological properties are considered together with synthetic approaches towards the natural products and bioactive analogues.

Highly Functionalized Ring B Labdane Synthesis as Key Intermediate in the Route to Forskolin.

Sclareol has been employed as starting material for the synthesis of several advanced intermediates towards the synthesis of highly ring B oxygenated labdanes. Dinorlabdanes 6,7,8,9-tetraoxygenated with 6,7-dioxygenated functionalities with a-cis or O-cis dispositions, have been prepared and can be used for forskolin or analogues synthesis.

Antioxidant Activity of Carvone and Derivatives against Superoxide Ion.

Carvone has corroborated its versatility as starting material for building blocks synthesis in organic chemistry, being achieved a new chiral lactone. It has been done a study on the antioxidant activity against superoxide of carvone and a chloro derivative that show the potent activity of the natural product (R)-carvone, 1.

Crystal structure of methyl (4)-4-(4-meth-oxy-benzo-yl)-4-{[(1)-1-phenyl-eth-yl]carbamo-yl}butano-ate.

The title compound, CHNO, was prepared by CAN [cerium(IV) ammonium nitrate] oxidation of the corresponding β-lactam. The dihedral angle between the benzene rings is 13.3 (4)° and the C-N-C(=O)-C torsion angle is 176.

Crystal structure of (2*,3a*)-2-phenyl-sulfonyl-2,3,3a,4,5,6-hexa-hydro-pyrrolo-[1,2-]isoxazole.

The title compound, CHNOS, was prepared by 1,3-dipolar cyclo-addition of 3,4-di-hydro-2-pyrrole 1-oxide and phenyl vinyl sulfone. In the mol-ecule, both fused five-membered rings display a twisted conformation. In the crystal, C-H⋯O hydrogen bonds link neighbouring mol-ecules, forming chains running parallel to the axis.