Isolation and Preliminary Purification of Polymyxin 3771 corresponding alcohol, tryptophol (IV), by the excellent method of Nystrom and Brown.9 An ether solution of III was treated with lithium aluminum hydride, suspended in ether, to give IV in good yield (65%). Experimental 3-Indoleacetic Acid (III).-Gramine (II) was prepared by the Mannich reaction on indole (I) according to the method of Kuhn and Stein.7 A mixture of 25.0 g. of gramine (II), 35.2 g. of sodium cyanide, 280 ml. of 95% ethyl alcohol and 70 ml. of water was boiled for eighty hours.To the cooled reaction mixture was added 350 ml. of water.The solution was treated with Norite, filtered, concentrated under reduced pressure until all the alcohol had been removed, cooled to 5°and filtered. The solid on the funnel (7.0 g., m. p. 145-150°) was recrystallized from alcohol and ether to give 5.0 g. of 3-indoleacetamide, m. p. 149-151 °. A sample of the amide, prepared for analysis by recrystallization from absolute alcohol and petroleum ether, was found to melt at 153 °. The amide has been previously reported to melt at 150-151 °.10>6

The antibiotic polymyxin occurs in the cell-free fermentation liquor of a strain of Bacillus polymyxa isolated in these laboratories. The origin, production, isolation, and biological activity of this substance have been briefly described in a previous publication (Stansly, Shepherd, and White, 1947). The present communication describes in detail a method for the routine pro