The 3,5-disubstituted tetrahydro-2H-1,3,5-thiadiazine-2-thione scaffold have found many applications in recent years. This review is aimed at highlighting the most important aspects about these compounds: synthesis, spectroscopic characterization and antiprotozoan activities. How the chemical nature of N-substituents influences the overall activity / cytotoxicity profile will also be discussed.

The Diels-Alder cycloadducts of 4-vinylimidazoles and N-phenylmaleimide are shown to undergo facile intermolecular ene reactions. Overall the reaction of three simple molecules (a diene, a dienophile and an enophile) in a two-step process gives 4,5,6,7-tetrahydro-1H-benzo[d]imidazoles with high yields, high atom economy and diastereocontrol of up to 5 new stereocentres.

The intramolecular Staudinger-aza-Wittig reaction is used for a general synthesis of 1,2,5,6-tetrahydro-1,2,4-triazines, a structural motif reported for the natural product noelaquinone. The DEF moiety of noelaquinone was obtained in 13 steps and 2% overall yield, and the structure of the synthetic product was confirmed by X-ray analysis.

Total control of axial and helical chirality elements of a (2-biphenyl)-substituted tetrahydro[5]helicene quinone and the configurationally stable dihydro[4]helicene analogue was achieved in a dynamic kinetic resolution process of an axially chiral racemic diene promoted by an enantiopure sulfinyl benzoquinone.

The microwave-assisted three-component reactions of 3,5-bis(E)-arylmethylidene]tetrahydro-4(1H)-pyridinones, acenaphthenequinone and cyclic α-amino acids in an ionic liquid, 1-butyl-3-methylimidazolium bromide, occurred through a domino sequence affording structurally intriguing diazaheptacyclic cage-like compounds in excellent yields.

A novel method for the preparation of (±)-methyl 1,1a,2,7b-tetrahydro-2-oxocyclopropa[c] chromene-1a-carboxylate has been developed. The cyclopropanation of methyl coumarin-3-carboxylate provided title compound in moderate yield by dropwise treatment with 1.5 equiv. of dimethylsulfoxonium methylide over 6 h. The structure of the newly synthesized compound was determined using 1H-, 13C-NMR, IR a...

An efficient and broadly applicable alternative to the classical Pictet-Spengler synthesis of tetrahydro-β-carbolines is presented. The method relies on metal-catalyzed isomerization of allylic amines to form reactive iminium intermediates which can be trapped by a tethered indole nucleophile.

Remarkable generality in scope of DATs/Cu catalysts for enantioselective nitroaldol reaction is described; excellent levels of stereoinduction are recorded for a range of aldehydes (ee 81-99%, 17 examples) and the possibility to employ the present catalytic system as the key step for the preparation of highly functionalized tetrahydro-isoquinolines is demonstrated.

The rhodium-catalyzed reactions of 3-diazoindolin-2-imines with N,N-dialkylanilines, N-allyl-N-alkylanilines, and N-propargyl-N-alkylanilines and 3-diazoindolin-2-imines furnished 3-aryl-2-aminoindoles, 3-allyl-3-amino-2-iminoindolines, and tetrahydro-[1,4]diazepino[2,3-b]indoles, respectively. 3-Diazoindolin-2-imines acted as precursors of α-imino rhodium carbenes in these transformations.

In a continuation of our studies into indan and tetralin systems as novel modulators of allergic and inflammatory phenomena, we have extended our work to include dimers linked via C-C bonds. Of these compounds, 2-Benzyl-2-[2-phenyl-1-ethenyl]-1,2,3,4-tetrahydro-1-naphthalenol 12 exhibited most promising activity both in vitro and in vivo.