Optically active amines. XVII. Partial kinetic resolution of .alpha.-phenylbutyric acid using chiral primary amines and their salts

Abstract

In conclusion, the ring bromination of kojic acid derivatives takes place at the 6 position, but the reaction occurs only when the 5-hydroxyl is free. Experimental SectionBromination of Chlorokojic Acid (2) with NBS. A mixture of 1.54 g of 2, 1.8 g of NBS, and 10 ml of CeHe was refluxed for 1 hr and was concentrated under vacuum.The residue was washed with water and recrystallized twice from absolute C2H5OH to yield 0.49 g of 3: mp 162-163°; positive Feds; ir (Nujol) 3150, 1580 cm-1.Bromination of Kojic Acid Monoacetate (9) with NBS. The same procedure was used with 0.197 g of 9, and yielded 0.217 g of 11 after recrystallization from CCI4, mp 131-133°, ir (Nujol) 3350, 1740, 1640 cm-1.

Stereoselective Synthesis of α-Arylalkylamines by Glycosylation-induced Asymmetric Addition of Organometallic Compounds to Imines

“…Comparison of the optical rotation value of the obtained product 12 ([α] 22 D = +5.82 (c = 2, EtOH)) with that given in the literature [22] ([α] 22 D = +5.1 (c = 2.0, EtOH)) confirmed that the major diastereomer of 10 had (S) configuration.…”

Efficient Transformation of Azides to Primary Amines Using the Mild and Easily Accessible CeCl3·7H2O/NaI System

“…Further, it is known that the CeCl 3 ·7H 2 O/NaI system allows the reactions to be carried out in close to neutral conditions and thus allows the survival of a large variety of functional groups or protecting groups sensitive to acidic hydrolysis. ,20c Azides bearing stereogenic centers (Table , entry 10) can be converted giving the amines with complete retention of the original configuration. The azide 1l obtained from l -menthol via stereospecific S N 2 displacement undergoes smooth conversion to the corresponding chiral amine 2l , but in less than optimal yields . The formation of other byproducts has been evident, the identity of which remains unknown.…”