Synthesis and Crystal Structure Analysis of 1‐Methyl‐3,6‐Diphenyl‐6aλ⁴‐Thia‐1,2,5,6‐Tetra‐Azapentalene

Abstract

1,6 ,6a X4-Trithiapentalenes 1 are bicyclic aromatic 107 -electron systems which are characterized by a linear S-S-S arrangement and single bond/no bond properties. This is also the case for 6ah -thia-l,3,4,6-tetra-azapentalenes We have now developed a third synthetic method for 2 which involves the condensation of a 1,2, 3-thiadiazole-5-carbaldehyde5 (e.g. 4) with phenylhydrazine, followed by methylation and treatment with a base. The red crystalline product -5 (mp 142'C), obtained in 21% overall yield, exhibits IR, '€I NMR and I3C NMR, and MS data which are in full agreement with its structure. x 0.7 x 0.07 mm were measured using a Huber 4-circle diffractometer and a Rigaku rotating anode X-ray generator providing graphite-monochromatized CuK,-radiation (A = 1.54178 f i ) . Of the 2655 hkil.independent reflections withsin@/A Intensities from a parallelepiped crystal 0.2 -949 -