Suspension, evaporative cooling solids concentration

A solution of the 2p,3[3-epoxy-5a-androstan-17-one (30.0 g) in ethanol (130 ml), water (15 ml) and liquid ammonia was heated in an autoclave at 150°C for 6 h and the resultant crystalline suspension evaporated to dryness. Water (35 ml) and acetic acid (36 ml) were added and the solution kept at 90°C for 1 h, cooled and excess water added. The precipitated material was filtered off and the filtrate made alkaline with aqueous 10 N potassium hydroxide solution to precipitate a white solid which was filtered off, washed neutral with water, dissolved in methylene chloride, the solution dried (Na2S04) concentrated and ether added to give 2p-hydroxy-3a-amino-5a-androstan-17-one (14.3 g), melting point I92°-195°C. 

In the proposed method, the hydroclone system is periodically isolated from the reactor and allowed to cool to 100°C. The hydrolyzed solids remain as such, but the rare-earth sulfate solids concentrated in the underflow pot redissolve upon cooling. The contents of the underflow pot are discharged to a centrifuge where solids are separated from the uranium-containing solution and w ashed wdth D2O, the suspension being sent to a wmste evaporator for recovery of D2O. 

A suspension of 40 g 3-acetylaminomethyl-5-amino-2,4,6-triodobenzoic acid in 180 ml acetic anhydride were mixed with 0.4 ml concentrated sulfuric acid. An exothermic reaction was thereby initiated. Acetylation was completed by heating to 80°C for three hours. The reaction mixture was then evaporated to dryness in a vacuum at a temperature not exceeding 50°C. The residue was treated with a mixture of 30 ml concentrated aqueous ammonium hydroxide and 40 ml water, whereby the solid material dissolved with spontaneous heating. Within a few minutes, the ammonium salt of the acetylated product started precipitating. The precipitate and residual liquid were cooled externally with ice after about 15 minutes. The salt was separated from the liquid by filtration with suction, and was washed with ice cold saturated ammonium chloride solution. 

A solution of diethylenetriamine (0.077 g, 0.74 mmol) in methanol (10 mL) is added with stirring to a suspension of cw-Pt(dmso)2Cl2 (0.30 g, 0.71 mmol) in methanol (50 mL), and the mixture is heated under reflux for 1 h. The resulting clear solution is concentrated in a rotary evaporator to 5 mL and then is cooled to room temperature. Chloroform (60 mL) is added with stirring to precipitate the product as a gelatinous white solid that becomes powdery on cooling the flask in an ice bath for 10 min. The solid is filtered off, washed first with chloroform and then with diethyl ether, and air-dried. Yield 0.254 g, 96%. The product is recrystallized from an aqueous solution (2 mL) by careful addition of acetone. The precipitate is collected, washed first with acetone and then with diethyl ether, and finally dried in vacuo over P2O5. 

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