Syntheses of, and structural studies on, benzo-fused 1,2,4-thiadiazinesElectronic supplementary information (ESI) available: Full experimental details and analytical data for 1-9; a cif file containing the crystal structures of 1-9 and selected intermediates. CCDC 969012-969022. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c3ce42205d

The syntheses of nine benzo-fused-1,2,4-thiadizines are reported. The use of microwave synthesis has been shown to afford high yields and short reaction times in several key reaction steps. The molecular geometries of these heterocycles are discussed and their solid state packing motifs reveal a strong tendency for the N-H group to form hydrogen bonded chains. Structural characterisation of a series of benzothiadiazines reveal a propensity for the N-H group to act as a hydrogen bond donor. The hydrogen bond acceptor strength of the remaining heterocyclic N is probed by adjusting the hydrogen-bond acceptor strength of the R-substituent.