The chemistry of small ring compounds. Part 41: Methylenethiirane, an isomer of cyclopropanethione

The cyclic carbonate 3, prepared from bis(1‐hydroxycyclopropyl) sulfide and phosgene, has been thermolysed at 500° and 0.5 mm, yielding methylenethiirane (4), an isomer of cyclopropanethione. The structure of 4 is supported by mass spectrometry, 1H‐ and 13C‐NMR and infrared (in vapour phase and in solution). Attempted reactions with methyl fluorosulfate, diazomethane, triphenylphosphine and 1,3‐diphenylisobenzofuran all lead to polymeric material of uncertain structure.