sonogashira
posted on 28-5-2007 at 06:12 PM
Solo, here's the abstract from the article you requested (from sci-finder), hopefully it has the experimental details you're after:
Reductive amination of phenylacetylcarbinols by sodium borohydride. Weichet, J.; Hodrova, J.; Blaha, L. Vyzlumny Ustav Farm.
Collection of Czechoslovak Chemical Communications (1961), 26 2040-4
Abstract
The technologically attractive NaBH4 is a suitable agent, since no extensive racemization occurred; however, the course of the reaction was less
stereospecific than in the catalytic process with colloidal Pt to yield a mixt. of erythro and threo forms of the corresponding aminoales. in approx.
3-4:1 ratio. Thus, 7.5 g. p-fluorophenylacetylcarbinol (I)treated in 50 ml. MeOH at 0-5° with 15 ml. aq. 36% MeNH2, in 25 min. 1.5 g. NaBH4 added
portionwise, the mixt. stirred 1 hr., 5 g. K2CO3 added, excess MeNH2 and MeOH distd. in vacuo, dild. with 20 ml. H2O, the product extd. with Et2O, the
exts. dried, and satd. with HCl gave 7.1 g. crude HCl salt, m. 195-205°, which yielded 1.5 g. p-fluoropseudoephedrine, m. 114° (H2O or cyclohexane);
HCl salt m. 170° (Me2CO). The mother liquors gave 4.5 g. p-fluoroephedrine-HCl, m. 234° (90% EtOH); free base m. 76°. Similarly were obtained 5.5
g. ephedrine-HCl, m. 186-8° (base m. 76-8°) and 1.8 g. pseudoephedrine, m. 117° (HCl salt m. 164°), from 10 g. phenylacetylcarbinol (II) and 0.6
g. NaBH4, 15.6 g. optically active ephedrine-HCl, m. 216-17°, [a]20D -34°, from 15 g. (-)-II, 6.8 g. m-hydroxyephedrine-HCl, m. 183-5°, from 8.3 g.
m-hydroxyphenylacetylcarbinol (III), N-(b-hydroxyethyl)norephedrine, m. 110° (HCl salt m. 164-6°), from II and HOCH2CH2NH2, and N-butylnorephedrine,
m. 70° (HCl salt m. 219-20°), from II and BuNH2. m-Hydroxyphenylethynylcarbinol, obtained by addn. of C2H2 to m-C6H4CHO in liquid NH3, decompn. of
the mixt. with ice, extn. with Et2O, and crystn. from C6H6 gave 74% crystals, m. 101-4°. Hydration of the ethynylcarbinols according to the method of
Hennion and Fleck (CA 50, 3203c) gave 77.5% I, b8 115-16°, n20 1.5095, 66.5% II, b14 124-6°, n20 1.5330, and 90% III, m. 98° (C6H6).
|