81602-13-3Relevant academic research and scientific papers
Resolution of racemic amines via lipase-catalyzed benzoylation: Chemoenzymatic synthesis of the pharmacologically active isomers of labetalol
Sanfilippo, Claudia,Paternò, Alfio Adriano,Patti, Angela
, p. 79 - 84 (2018/04/30)
Lipase-catalyzed benzoylation of amines was shown to be feasible, in some cases with high enantioselectivity, and the best results were obtained using immobilized lipase from Candida antarctica (Novozym 435) and methyl benzoate as acyl donor in the presence of molecular sieves. The procedure was optimized for the resolution of (±)-1-methyl-3-phenylpropylamine, a key intermediate in the synthesis of antihypertensive drug labetalol, and the enantiopure (R)-benzamide was then converted into the pharmacologically active isomers of the drug. In comparison with the reported synthesis of chiral isomers of labetalol, this chemoenzymatic route offers the advantage in the lack of any chiral stoichiometric auxiliary.
Synthesis and Comparison of Some Cardiovascular Properties of the Stereoisomers of Labetalol
Gold, Elijah H.,Chang, Wei,Cohen, Marvin,Baum, Thomas,Ehrreich, Steward,et al.
, p. 1363 - 1370 (2007/10/02)
A useful method for the separation of labetalol into its two racemic diastereomers, as well as a stereoselective synthesis of its four stereoisomers, is described.The absolute stereochemistry of each isomer was determined by analysis of the CD spectra and confirmed by X-ray analysis.The α- and β1-adrenergic blocking properties, as well as the relative antihypertensive activities, have been measured in rats.The R,R isomer, 2a (SCH 19927), possesses virtually all of the β1-blocking activity elicited by labetalol and displays little α-blocking activity.In contrast, the S,R isomer, 3a, has most of the α-blocking activity.Of the four isomers, only 2a has antihypertensive potency comparable to that of labetalol.These findings, coupled with published data showing that labetalol possesses β-adrenergic mediated peripheral vasodilating activity deriving essentially from its R,R isomer, lead to the following conclusion: The antihypertensive activity of labetalol can be ascribed to at least three identified complementary mechanisms, β-adrenergic blockade, β-adrenergic mediated vasodilatation, and α-adrenergic blockade, whereas the antihypertensive activity of 2a derives from the first two mechanisms only.
