Pyrrolo[1,4]benzodiazepines are tricyclic compounds that are considered “privileged structures” since they possess a wide range of biological activities. The first encounter with these molecules was the isolation of anthramycin from cultures of Streptomyces, followed by determination of the X-ray crystal structure of the molecule and a study of its interaction with DNA. This opened up an intensive synthetic and biological study of the pyrrolo[2,1-c][1,4]benzodiazepines that has culminated in the development of the dimer SJG-136, at present in Phase II clinical trials. The synthetic efforts have brought to light some new synthetic methodology, while the contemporary work is focused on building trimeric pyrrolo[2,1-c][1,4]benzodiazepines linked together by various heterocyclic and aliphatic chains. It is the broad spectrum of biological activities of pyrrolo[1,2-a][1,4]benzodiazepines that has maintained the interest of researchers to date whereas several derivatives of the even less studied pyrrolo[1,2-d][1,4]benzodiazepines were found to be potent non-nucleoside HIV-1 reverse transcriptase inhibitors. The present review is an update on the synthesis of pyrrolo[2,1-c][1,4]benzodiazepines since the last major review of 2011, while the overview of the synthesis of the other two tricyclic isomers is comprehensive.

N,N-Dimethylformamide was found to act as solvent and catalyst in the dehydration of aldoximes to nitriles. The reaction ­required heating at 135 °C and yields of nitriles were moderate to good. (Benzylideneaminooxy)formaldehyde was detected as an ­intermediate in one of the reactions.

A simple and efficient one-pot cascade reaction for the regioselective synthesis of trans or cis/trans 2,3-disubstituted 2,3-dihydrobenzofurans is reported. The method involves fluoride-induced desilylation, generation of o-quinone methide (o-QM) by chloride or nitrate anion elimination, Michael addition and intramolecular 5-exo-tet elimination of a bromide anion. Nitrate, acetoxy and chloride anions are compared as leaving groups in the formation of the in situ generated o-QM.