Abstract The reaction of 1, 3-disubstituted thioureas with formaldehyde under acidic conditions with removal of water yielded 3, 5-disubstituted tetrahydro-4H-1, 3, 5-oxadiazine- 4-thiones. When hydrogen sulfide was bubbled through the reaction mixture, the corresponding tetrahydro-4H-1, 3, 5-thiadiazine-4-thiones were formed. Similarly, starting from 1, 3-disubstituted ureas, a number of tetrahydro-4H-1, 3, 5-thiadiazine-4-ones were ...
