Yellow sulfur

Investigation into the stmcture of the sulfur-bake dye Immedial Yellow GG, Cl Sulfur Yellow 4 [1326-75-6] (Cl 53160), by chemical degradation of the dye and confirmatory synthesis of the postulated stmctures showed that a mixture of four dyes was obtained when benzidine and 4-(6-methyl-2-hen7othia7o1y1)ani1ine were baked with sulfur. The original British patent for Sulfur Yellow 4 dates back to 1906 (19). The principal stmcture obtained is (1). 

Coloring agents are used in pharmaceutical preparations for purposes of esthetics. A distinction should be made between agents that have inherent color and those that are employed as colorants. Certain agents such as sulfur (yellow), riboflavin (yellow), cupric sulfate (blue), ferrous sulfate (bluish green), and cyanocobalamin (red), have inherent color and are not thought of as pharmaceutical colorants in the usual sense of the term. 

Thiosalicylic acid/747-93-3] (0-mercaptobenzoic acid), a sulfur-yellow solid that softens at 158°C, has a melting point of 164°C. It sublimes, is slightly soluble in hot water but freely soluble in glacial acetic acid and alcohol, and yields dithiosalicylic acid [527-89-9] upon exposure to air. 

The principal features of elemental sulfur in the displayed T, P range are the usual liquid and vapor phases and two solid forms, a-sulfur ( red sulfur, of orthorhombic crystalline form) and /3-sulfur ( yellow sulfur, monoclinic needle-like crystals), both of which are available as common stockroom species. The stable phase ranges for each elemental form are shown by the solid lines in Fig. 7.5. The liquid-vapor coexistence line terminates in a critical point at 1041°C, and will not be discussed further. 

Sulfur Yellow powder None No effect when hot or cold... 

Fig. 13.19. Examples of sulfur yellow (left) and red (right) dye structures.

Carbon, black Hydrogen, white Nitrogen, blue Oxygen, red Sulfur, yellow Phosphorus, purple... 

Figure 8. Probe map of E. coli dihydrofolate reductase-methotrexate (10) complex. The calculated minimum energy positions for an ammonium probe (blue) and carboxylate oxygen probe (yellow) closely match the experimental positions for the pteridine amino groups and the carboxyl of methotrexate (20,21). The molecular surface of the enzyme is purple, while all bonds are color-coded by atom type carbon = white, nitrogen = blue, oxygen = red, sulfur = yellow. 

FIGURE 3.1 One mole each of several common elements copper (as pennies), iron (as nails), carbon (black charcoal powder), sulfur (yellow powder), and mercury (shiny liquid metal). 

Sulfur-yellow needles from alcohol or acetone, mp 241. Moderately strong base. K (25 ) 3 X 10 . Freely sol in alcohol slightly sol in chloroform, toluene, pyridine sol in... 

Yellow hydrated needles from water or dil ale. Slightly bitter, astringent taste. The water of crystn (about 3 mols) is removed at 130 and 0.2 mm Hg. The anhydr substance, mp 205 (rapid heating). Sparingly sol in cold water freely sol in hot water, hot alcohol practically insol in ether. Alkaline solns are sulfur-yellow and nn dilution show characterisitic blue-greeu fluorescence. 

Sulfur yellow, almost odorless and tasteless, crystalline powder, mp 260-270" (dec). One gram dissolves in 500 ml cold, 170 ml boiling water slightly sol in aleohol. Practically insol in ether or oils. 

Sulfur-yellow flakes, plates, needles from glacial acetic acid or alcohol. Softens at 158. mp 164-165. Sublimes. Slightly sol in hot water freely in glacial acetic acid, ale. Exposure to air yields dithiosalicylic acid, which is produced also when an alcoholic soln of thiosalicylic acid comes in contact with FeClj (resulting in a transitory blue color). 

Sulfur-yellow crystals, mp 286. uv max (water) 243, 342 nm (e 30,000, 6500) Insol in water. Sol in aq alkali hydroxides and carbonates (ydlow solns) and in hot dil HC[. It gives a red color with Mitlon reagent, intense ruby-red with alkali diazobenzenesulfonates, and intense green with FeS04. When the acid is dissolved in very dil NaHCOj, the green color with FeSOj is still visible at a diln of 1 200,000. 

Methylbenzoylacetone (2-methyl-1-phenyl-1,3-butanedione) 400 401 The calculated amount of sodium wire is added to benzoylacetone dissolved in six times its amount of anhydrous ether. This precipitates the sodio derivative as a sulfur-yellow powder. For further reaction402 a portion (3 g) of this derivative is dried over phosphoric oxide and heated for 4 h under reflux with methyl iodide (1.9 g) in anhydrous acetone (50 ml). The acetone is then distilled off and the residue is taken up in ether, shaken with water, dried, and fractionated, giving 88% of the product, b.p. 130-134°/11 mm. 

To a solution of 10.0 g. (0.0241 mol) of potassium tetra-chloroplatinate(II) in 100 ml. of water contained in a 400-ml. beaker is added vdth continuous mechanical stirring a solution of 3.90 ml. (3.84 g. 0.0495 mol) f of pure pyridine (density, 0.982 g./ml.) in 25 ml. of water. In a few minutes, a sulfur-yellow precipitate begins to form. The stirring is continued for several hours then the mixture is allowed to stand in a refrigerator until precipitation appears complete (about 24 hours). The precipitate is then separated from the very pale yellow supernatant liquid by means of a 5-cm. sintered-glass funnel, washed several times with ice water to remove potassium chloride, air-dried, and finally dried at 100° for one hour. The yield is 9.15 g. (89.4%). Anal. Calcd. for [Pt(C6H5N)2Cl2] Pt, 46.01. Found Pt, 45.83. 

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