Reactions of aminophenols with formaldehyde and hydrogen sulfide

The reaction of m-aminophenol with CH2O and H2S (1:2:1 ratio) afforded 2,12-dioxa-4,14-dithia-6,16-diazatricyclo[15.3.1.1(7,11)]docosa-1(20),7(22),8,10,17(21),18-hexaene in similar to 9% yield. Aminophenol o- and p-isomers react with CH2O and H2S (1:3:2) to form 2- and 4-[4H-1,3,5-dithiazin-5(6H)-yl]phenols in 86 and 71% yields, respectively. In the crystal structure of the latter, molecules contain dithiazine cycles in the chair conformation with the axial hydroxyphenyl group. Molecular packing represents a combination of molecules forming chains due to the OH...S intermolecular hydrogen bond.