stains from negatives; thiuret, C₆H₇N₃S₂, serves as a substitute for iodoform; thiosinamine-ethyliodide, or tiodine, IH₅C₂H₂NCSNHC₃H₅, is used for relief of lesions of the central nervous system; allylthiourea or thiosinamine, (NH₂)SC.NHCH₂CH:CH₂, for aiding the absorption of connective tissues, for treatment of burns, keloids, urethral diseases, sclerotic conditions of the ear(23).

Selenocarbamide and a number of its derivatives have been prepared and studied. One class of seleno ureas has been patented as pharmaceutical products by Chem. Fabrik von Heyden(24), and are prepared by the action of hydrogen selenide on alkylcyanamides,

RNH.CHN + H₂Se = RNH.CSe.NH₂

They possess pronounced therapeutic value and, serve as intermediate products in the production of more stable alkyl halide additive compounds. Other carbamides ranging from seleno urea itself(25), (III) and a cyclic urea(26) (IV) are described in the literature:

The latter, known as ethylene-selenourea, may be classified also in the azole group as 2-iminotetrahydroselenazole (V).

The literature for the other normal carbamides is listed in the bibliography(27).

Selenoantipyrines, selenosaccharine, selenoindigoes have also been prepared.

Thiophene and its derivatives are of considerable therapeutic interest. Thiophene itself is found to be useful in lessening the elimination of sulphuric acid in urine, and is employed in the dermatological practice. Sodium thiophene sulphonate, thiophenetetra-bromide, thiophene diiodide, are all medicinals(23).

A number of selenophenes are recorded in the literature. Their relation to the selenazoles may be easily seen from the following formulas:

Selenophene

Selenazole

Dimethyl selenophene was prepared from acetonyl acetone and phosphorous pentaselenide,

The compound thus obtained is stated to have the same odor as thiophene, but no mention is made in regard to its uses(28). Selenophene was prepared from sodium succinate and phosphorous triselenide, or by conducting ethylselenide through hot tubes(29).

Some selenazoles find application also in medicine. At present only the isoazoles are known to have physiological uses. One of them was prepared from anthraquinone selenocyanide, by the action of ammonia under pressure(30).

Another type of azoles, benzoselendiazole (piaselenol) and five of its derivatives, have been also described as medicinals(31). The diazole itself has the following structure,

or

Diazoles of the following structure are also known, but no data were found, regarding their physiological action(32):

Dimethyl-seleno-diazole

Diphenyl-seleno-diazole

Sulphides and disulphides have curative power. Dimethylsulphide is used for internal treatment, di-o-aminophenyldisulphide is used for intramuscular injections. Diallyl sulphide is also a medicament. Methyl selenide has some effect on the internal parts of the body(33). Hanzlik and Tarr(34) at the American University Experimental Station, showed that a number of selenium compounds act as skin irritants: e.g., dichlorodiethyl selenide, dichlorovinyl selenide, trichlorodiethyl selenide and selenium mustard oil. The first mentioned proved as potent as the sulphide, but the others fell somewhat below in their effects. Diantipyryl selenide is another therapeutical agent(35).

The diselenides occupy an important place of their own. The selenophenols do not remain unchanged in the air, but are always oxidized to the diselenides, which can be again reduced to the selenophenols. So far only the diselenides of anthraquinone and their phenols are recognized remediespublic@vhost@g@gutenberg@html@files@46714@[email protected]#bib_36" class="fnanchor pginternal"