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The Smiles rearrangement is the intramolecular nucleophilic aromatic substitution reaction incorporating a heteroatom as the nucleophilic component and an activated electrophilic arene. One particular variation--the Truce-Smiles rearrangement--utilises a carbon-based nucleophile and an electrophilic arene which does not require additional activation. Such a variation generates a new carbon-carbon bond and the synthetic utility of this relatively under-utilised rearrangement is discussed in this tutorial review.

The semi-pinacol rearrangement is fast becoming an extremely reliable reaction in organic synthesis allowing the rapid construction of relatively complex stereodefined products in high yield. Recent advances in asymmetric synthesis have also enabled enantiopure precursors to partake in the rearrangement showing that extremely high levels of stereospecificity are observed. In this critical review recent advances in the semi-pinacol rearrangement over the past 15 years are examined which demonstrate the extremely high utility of this reaction towards the development of structurally diverse organic building blocks (74 references).

HIGHLIGHTS• Brain cancer mortality rates are much higher than mortality rates for cancers of other sites. •Due to the blood brain barrier, many drugs that work on cancers of other sites do not work on brain cancers • Indoles, carbazoles and indolocarbazoles make good scaffolds for drugs to be built up around due to their rigidity, planarity and ease of synthesis. GRAPHICAL ABSTRACT ACRONYMS/INITIALISMSAML -Acute myeloid leukaemia CK2 -Casein kinase 2 CNS -Central nervous system PARP -Poly ADP ribose polymerase PDGF -Platelet-derived growth factor PKC -Protein kinase C ROS -Reactive oxygen species VEGF -Vascular endothelial growth factor ABSTRACT Tumours of the central nervous system are intrinsically more dangerous than tumours at other sites, and in particular, brain tumours are responsible for 3% of cancer deaths in the UK. Despite this, research into new therapies only receives 1% of national cancer research spend. The most common chemotherapies are temozolomide, procarbazine, carmustine, lomustine and vincristine, but because of the rapid development of chemoresistance, these drugs alone simply aren't sufficient for longterm treatment. Such poor prognosis of brain tumour patients prompted us to research new treatments for malignant glioma, and in doing so, it became apparent that aromatic heterocycles play an important part, especially the indole, carbazole and indolocarbazole scaffolds. This review highlights compounds in development for the treatment of tumours of the central nervous system which are structurally based on the indole, carbazole and indolocarbazole scaffolds, under the expectation that it will highlight new avenues for research for the development of new compounds to treat these devastating neoplasms.

Oligomeric ureas derived from m-phenylenediamine with chain lengths of up to seven urea linkages were made by iterative synthetic pathways. Three families were synthesized: 4 and 20, bearing a terminal chiral sulfinyl group; 24, bearing a terminal rotationally restricted amide group, and 30 bearing a terminal achiral bromophenyl group. The distal end of the oligomers was capped with an N-benzyl group to act as a diastereotopic probe. With a terminal sulfinyl group, the 1H NMR signals arising from the CH2 group of the diastereotopic probe remained anisochronous even when separated from the stereogenic center by up to 24 bonds (in 20c). With a rotationally restricted amide, anisochronicity was no longer apparent beyond 17 bond lengths (in 24c). No anisochronicity was observable with a terminal bromophenyl group. We interpret these results as indicating that the oligoureas of short lengths adopt a defined helical secondary structure in solution, but that in longer oligomers the helicity breaks down and transmission of chirality in these systems is limited to about 24 bond lengths. We propose that "apparent diastereotopicity" (anisochronicity) provides a general empirical method for identifying secondary structure in solution.

A template-based mnemonic has been developed for the enzyme monoamine oxidase from Aspergillus niger and has been used to successfully identify the alkaloid (+/-)-crispine A as a target for chemo-enzymatic deracemisation yielding the biologically active (R)-enantiomer in 97% e.e.

Nuclear factor-B (NF-B), a transcription factor with a critical role in promoting inflammation and cell survival, is constitutively activated in estrogen-receptor (ER)-negative breast cancer and is considered a potential therapeutic target for this type of neoplasia. We have previously demonstrated that cyclopentenone prostaglandins are potent inhibitors of NF-B activation by inflammatory cytokines, mitogens, and viral infection, via direct binding and modification of the ␤ subunit of the IB kinase complex (IKK). Herein, we describe the NF-B-dependent anticancer activity of natural and synthetic cyclopentenone IKK inhibitors. We demonstrate that the natural cyclopentenone 15-deoxy-⌬ 12,14 prostaglandin J 2 (15d-PGJ 2 ) is a potent inhibitor of constitutive IB-kinase and NF-B activities in chemotherapy-resistant ER-negative breast cancer cells.15d-PGJ 2 -induced inhibition of NF-B function is rapidly followed by down-regulation of NF-B-dependent antiapoptotic proteins cIAPs 1/2, Bcl-X L , and cellular FLICE-inhibitory protein, leading to caspase activation and induction of apoptosis in breast cancer cells resistant to treatment with paclitaxel and doxorubicin. We then demonstrate that the cyclopentenone ring structure is responsible for these activities, and we identify a new synthetic cyclopentenone derivative, 3-tert-butyldimethylsilyloxy-5-(E)-iso-propylmethylenecyclopent-2-enone (CTC-35), as a potent NF-B inhibitor with proapoptotic activity in ER-negative breast cancer cells. The results open new perspectives in the search for novel proapoptotic molecules effective in the treatment of cancers presenting aberrant NF-B regulation.

Privileged structures bind to multiple receptors with high affinity, thus aiding the development of novel biologically active compounds. Indoles are classed as privileged structures, and as a result of the indole nucleus being present in a broad range of biologically active molecules, it has been suggested that indoles probably represent the most important of all structural classes in drug discovery. Amongst the indole class of compounds is a particular subset - 2-arylindoles - which appear to be a most promising lead for drug development. This review summarises the wide-ranging activities of 2-arylindoles and some of their important biological activities reported in the literature over the past two decades.