124 Dr. J. Stenhouse on Amido-derivatives of Orcin. [Jan. 23, 



place, so that it is advisable to remove the flask from the source of heat in 

 order to prevent the contents from boiling over. When the action has 

 become somewhat moderate, the solution is boiled until it is colourless, 

 then diluted with water and the tin precipitated by hvdrosulphuric acid. 

 The clear solution acquires a purple tint on standing, and deposits large 

 dark-coloured prisms of amido-d i i m i do-or cin hydrochlorate, or the amido- 

 diimido-orcin may be obtained directly by adding a slight excess of am- 

 monia to the filtrate from the tin sulphide and oxidizing by agitation in 

 the presence of air, when the base immediately separates in minute green 

 needles. Trinitro-orcin and granulated zinc are boiled in a flask with 

 twenty or thirty parts of water, and hydrochloric acid added in small 

 quantities at a time until the solution becomes almost colourless. The 

 clear liquid, poured from the excess of zinc and allowed to cool, is ren- 

 dered slightly alkaline by ammonia and exposed to the air. As soon as 

 the triamido-orcin is oxidized, which may be known by the brown colour 

 of the product, an excess of hydrochloric acid is added to dissolve the zinc 

 oxide and precipitate the amido-d i i m i do-or cin as hydrochloride. The yield 

 is, however, considerably less than when sodium-amalgam is employed as 

 the reducing agent. 



The amido-diimido-orcin sulphate or hydrochlorate obtained by any of 

 the above processes is readily decomposed by treatment with a slight ex- 

 cess of dilute ammonia, leaving the free base in an impure state. This 

 should then be dissolved in warm dilute acetic acid, filtered, and precipi- 

 tated by a slight excess of ammonia. Two or three solutions and repre- 

 cipitations are sufficient to render it pure. 



Pure amido-diimido-orcin crystallizes in small needles, which have a dark 

 green metallic lustre by reflected fight. They are insoluble in alcohol, 

 ether, and benzol, and almost insoluble in water and dilute ammonia. 

 Strong ammonia only dissolves the base in small quantity, gelding a pale 

 blue solution, but it is readily soluble in a solution of sodic hydrate, with 

 a fine deep blue colour ; the solution, however, when boiled, loses its 

 colour, ammonia being at the same time evolved. The base gives off am- 

 monia when heated, and leaves a carbonaceous residue very difficult of 

 combustion. As might be expected, when amido-diimido-orcin is treated 

 with sodium-amalgam, it is reconverted into triamido-orcin. 



Analysis of amido-diimido-orcin. — -290 grm. substance, dried in vacuo, 

 lost -025 grm. when dried at 100°, equivalent to 8*62 per cent. 



I. -140 grm. substance, dried at 100°, gave -234 grm. carbonic anhy- 

 dride and '075 grm. water. 



II. '290 grm. substance, dried at 100°, gave "487 grm. carbonic anhy- 

 dride and '152 grm. water. 



