sodium tetrahydroborate in water 1 h;

sodium tetrahydroborate in water 1.) 0 deg C, 15 min, 2.) room temperature, 30 min; Yield given;

in water to a soln. of pyridinium iodide in water (cooled in an ice bath) NaBH4 was added with stirring, mixt. stirred for 15 min at 0°C and 30 min at room temp.; extd. with ether, extract dried over Na2SO4 and evapd. to dryness; chromy. on silica gel column with CH2Cl2; elem. anal.;