Synthesis of Benzo[d]Benzo[2,3][1,4]Diazepino[1,7-b]Isothiazole, a New Heterocyclic Ring System

Reactivity Studies on a Novel 4-(2-hydroxyphenyl)-1,3-dihydro-1,5-benzodiazepine-2-thione

The novel 4-(2-hydroxyphenyl)-1,3-dihydro-1,5-benzodiazepine-2-thione (4) has been synthesised and used as precursor to the hitherto unreported 7-methylthio[1]benzopyrano[4,3-c][1,5]-benzodiazepine (7). Hydrazinolysis of 4 gave 5-(2-aminophenylamino)-3-(2-hydroxyphenyl)-1H-pyrazole (9) which with excess of N,N-dimethylformamide dimethylacetal formed the 5-(2-hydroxyphenyl-2H-pyrazol-3-yl)-1H-benzimidazole (10).

Synthesis and Spectral Characterization of Benzo-[6,7][1,5]diazocino[2,1-a]isoindol-12-(14H)-one Derivatives

A simple synthetic route affording 27%–85% yields of benzo[6,7][1,5]diazocino[2,1-a]isoindol-12(14H)-one ring systems from readily available 3-(2-oxo-2-phenylethyl) isobenzofuran-1(3H)-ones and 2-(aminomethyl)aniline starting materials in toluene and catalysed by p-toluene-sulfonic acid is developed. The ¹H- and ¹³C-NMR spectra of the final products were assigned using a variety of one and two-dimensional NMR experiments. The distinction between the two potential isomers of the final products was made on the basis of heteronuclear multiple bond connectivity (HMBC) NMR spectra.

Racemic 9,10-dimeth-oxy-3-methyl-6-phenyl-7,7a-dihydro-benzo[b]benzo[4,5]isothia-zolo[2,3-d][1,4]diazepine 12,12-dioxide

There are two molecules in the asymmetric unit of the title compound, C₂₄H₂₂N₂O₄S. The conformation of the seven-membered ring is twisted boat for both molecules. The molecule is chiral, but crystal symmetry generates a recemate. The crystal packing is stabilized by weak intermolecular C—H⋯O hydrogen bonds.