61347-73-7

Upstream product

• 134522-09-1 N-((1S,2S)-2-hydroxy-1-methyl-2-phenyl-ethyl)-benzamide; N-benzoyl-(+)-norpseudoephedrine 
• 169557-51-1 Acetic acid (1S,2S)-2-benzoylamino-1-phenyl-propyl ester 
• 190724-40-4 (4S,5S)-3-Benzyl-4-methyl-5-phenyl-oxazolidin-2-one 
• 61347-76-0 NH-benzyl-(1R,2S)-norephedrine 
• 3198-15-0 (1R,2S)-(-)-norephedrine hydrochloride 
• 100-52-7 benzaldehyde 
• 100-46-9 benzylamine 
• 579-07-7 1-Phenylpropane-1,2-dione 
• 67-56-1 methanol 
• 70735-98-7 (+/-)-4r-methyl-2ξ,5t-diphenyl-oxazolidine 
• 52597-17-8 2-(N-benzylamino)-1-phenyl-1-propanone 
• 1798-60-3 (R)-1-hydroxy-1-phenyl-2-propanone 
• 64-17-5 ethanol 
• 190782-97-9 Benzyl-((1S,2R)-2-hydroxy-1-methyl-2-phenyl-ethyl)-carbamic acid benzyl ester 

Downstream Products

• 159099-80-6 (1S,2S)-2-(N-benzyl-N-methylamino)-1-phenyl-1-propanol 
• 90-82-4 pseudoephedrine 
• 1240159-36-7 (1S,2S)-2-(N-benzyl-N-nitrosamino)-1-phenyl-1-propanol 
• 117693-80-8 (+/-)-3-benzyl-4r-methyl-2ξ,5t-diphenyl-oxazolidine 

Relevant academic research and scientific papers

Stereoselectrive Syntheses of Ephedrine and Related 2-Aminoalcohols of High Optical Purity from Protected Cyanohydrins

Ephedrine and related optically active β-aminoalcohols can be prepared by zinc borohydride reduction of aryl O-protected magnesium imines and aryl α-hydroxyimimes which in turn are readily available from optically active cyanohydrins.

Catalytic asymmetric addition of diethylzinc to aldehydes via chiral, non-racemic β-hydroxy and β-methoxy salicylhydrazone catalysts

(1S,2S)-Pseudoephedrine and (1S,2S)-pseudonorephedrine have been converted to their corresponding hydrazines and condensed with either o-salicylaldehyde or 2-hydroxy-1-naphthaldehyde to afford a series of β- hydroxysalicylhydrazones that have been employed in the asymmetric addition of diethylzinc to 2-naphthaldehyde in up to 56% ee. In addition to this, the Ephedra hydrazines were also condensed with the o-hydroxyacetophenone derivative to form related hydrazones. The use of these corresponding hydrazones in the asymmetric addition reaction with the diethylzinc did not yield improved enantioselectivities. Finally, Enders' hydrazine was used as a chiral scaffold for the synthesis of β-methoxysalicylhydrazones. These compounds were employed in the asymmetric addition of diethylzinc to a variety of aromatic aldehydes with enantiomeric excesses as high as 68% ee.

N-Pyridylmethylephedrine derivatives in the catalytic asymmetric addition of diethylzinc to aldehydes and diphenylphosphinoylimines

N-Pyridylmethyl-substituted Ephedra derivatives were synthesized by either direct alkylation or reductive alkylation of (1R,2S)-norephedrine, (1S,2S)-pseudo norephedrine, and (1R,2S)-ephedrine. These derivatives were then employed in asymmetric addition reactions with diethylzinc and aldehydes and diphenylphosphinoylimines. The use of the diastereomers from the Ephedra family allowed for a systematic evaluation of the contribution of the N-pyridylmethyl.

Diastereoselective reduction of α-aminoketones: Synthesis of anti- and syn-β-aminoalcohols

Reduction of N-t-BOC-protected-N-alkyl α-aminoketones with LiEt 3BH or Li(S-Bu)3BH furnishes protected syn-β-aminoalcohols with high selectivities. In contrast, removal of the BOC group followed by reduction of the aminoketone gives anti-β- aminoalcohols with variable selectivities. With aromatic ketones, selectivities are typically high while aliphatic ketones show mediocre to high selectivities depending on steric considerations.

Diastereoselectivity in the reduction of α-oxy- and α-amino-substituted acyclic ketones by polymethylhydrosiloxane

Diastereoselectivity in the reduction of α-alkoxy-, α-acyloxy-, and α-alkylamino-substituted ketones with polymethylhydrosiloxane (PMHS) in the presence of fluoride ion catalysis was investigated. High syn-selectivity was observed in the reduction of α-alkoxy, α-acyloxy, and α-dialkylamino ketones. Reduction of α-monoalkylamino ketone proceeded in anti-selective manner with moderate selectivity. The observed selectivity is explained based on Felkin-Anh and Cram-chelate models.

Preparation of 2-oxazolidinones by intramolecular nucleophilic substitution

Treatment of N-alkoxycarbonyl, N-benzyl protected β-amino alcohols with triphenylphosphine and hexachloroethane in 1,2-dichloroethane induces cyclization to 2-oxazolidinones, which are formed by intramolecular attack with inversion of configuration at the secondary alcohol. In contrast, mono N-substituted alkyl carbamates undergo chlorination under the same conditions.

(1S,2S)-2-Amino-1-phenyl-1,3-propanediol, a spin off from chloramphenicol manufacture, as chiral synthon for (1S, 2S)-pseudoephedrine and (R)-phenylalaninol

(1S,2S)-2-Amino-1-phenyl-1,3-propanediol (3a), a discarded optically active material in one of the processes for the manufacture of chloramphenicol, has been transformed into (S,S)-pseudoephedrine (4) and (R)-phenylalaninol (5). The opposite selectivity of highly regioselective oxidative ring opening of the benzaldehyde acetal of (1S,2S)-2-phthalimido-1-phenyl-1,3-propanediol by NBS and highly regioselective ring opening of the cyclic sulphite of the same substrate by LiBr are the key steps in the transformations respectively.

Applications of Optically Active Aryl Cyanohydrins in the Synthesis of α-Hydroxy Aldehydes, α-Hydroxy Ketones and β-Hydroxy Amines

Cyanohydrins, prepared in high optical purity from aryl aldehydes, have been converted into α-hydroxy aldehydes, α-hydroxy ketones and β-hydroxy amines without any racemization and frequently with good stereoselectivity for the erythro-diastereoisomer (>90percent) at the newly introduced stereogenic centre.