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.

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.

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.

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.

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.

Enantioselective synthesis of cis-decalins using organocatalysis and sulfonyl Nazarov reagents.

The first organocatalytic synthesis of cis-decalins using sulfonyl Nazarov reagents is reported. The Jørgensen's catalyst directs this highly enantioselective synthesis using different cyclohexenal derivatives.

Synthesis and biological activity of polyalthenol and pentacyclindole analogues.

A series of indole sesquiterpenes analogues of polyalthenol and pentacyclindole have been synthesized starting from ent-halimic acid in order to test their biological activity. These analogues include diverse oxidation levels at the sesquiterpenyl moiety and different functionalization on the indole ring. All synthetic derivatives were tested against a representative panel of Gram positive and Gram negative bacterial strains, and the human solid tumour cell lines A549 (non-small cell lung), HBL-100 (breast), HeLa (cervix), SW1573 (non-small cell lung), T-47D (breast) and WiDr (colon).

Sesquiterpenyl indoles.

The natural product sesquiterpenyl indoles are structural hybrids from farnesyl pyrophosphate and tryptophan or its precursors, often with unusual and complex structural features, many of them with interesting biological activities. In this review the compounds of this class known until now are classified, a biosynthetic approach of each group is proposed and a review of the synthesis or synthetic approaches is communicated.

Synthesis of a new chiral pyrrolidine.

The synthesis of a new chiral pyrrolidine has been performed using 2,3-O-isopropylidene-D-erythronolactol as a suitable starting material.

Synthesis of an ent-halimanolide from ent-halimic acid.

An efficient synthesis of ent-halimanolide 2 (15,16-epoxy-12-oxo-ent-halima- 5(10),13(16),14-trien-18,2beta-olide), from ent-halimic acid has been achieved, corroborating the structure of the natural compound and establishing its absolute configuration.

Synthesis of (R)-2-(benzyloxy)-tetrahydro-5,5-dimethylfuran by a new oxidative rearrangement.

The rearrangement under oxidative conditions of 3-(benzyloxy)-tetrahydro- 2,6,6-trimethyl-2H-pyran-2-carbaldehydes to afford a chiral protected tetrahydrofuran lactol is described.