57707-57-0

Upstream product

• 2749-11-3 (S)-Alaninol 
• 98-88-4 benzoyl chloride 
• 6168-72-5 2-Amino-1-propanol 

Downstream Products

• 157774-52-2 (-)-N-Benzyloxycarbonyl-D-alanyl-N'-benzoyl-L-alaninylester 
• 157774-51-1 (-)-N-Benzyloxycarbonyl-L-alanyl-N'-benzoyl-L-alaninylester 
• 33985-13-6 (S)-N-(2-hydroxy-1-methylethyl)benzamide 

Relevant academic research and scientific papers

ATROPISOMERIC 1,8-BISPHENOLNAPTHALENES AND THEIR USE IN ENANTIOSELECTIVE RECOGNITION AND ASYMMETRIC SYNTHESIS

This invention related to atropisomeric 1,8-bisphenolnaphthalenes and derivatives thereof of the general formula (I): which are useful in resolution of enantiomers, enantioselective recognition and asymmetric synthesis.

Synthesis, conformational stability, and asymmetric transformation of atropisomeric 1,8-bisphenolnaphthalenes

Highly congested, axially chiral 1,8-bisphenolnaphthalenes have been synthesized in 75% overall yield by palladium-catalyzed Suzuki coupling of 1,8-diiodonaphthalene and 4-methoxy-2-methylphenylboronic acid followed by regioselective formylation and deprotection. The C2-symmetric anti-stereoisomers of 1,8-bis(2′-methyl-4′-hydroxy-5′- formylphenyl)naphthalene, 5, and its diimine analogues 9 and 10 were found to be significantly more stable than the corresponding syn-isomer. Crystallographic analysis revealed that this stereochemical preference results from a unique intramolecular hydrogen bonding motif and concomitant minimization of steric repulsion. Triaryl 5 proved stable to rotation about the chiral axes at room temperature and the enantiomers were isolated via formation of diastereomeric diimines with (R)-2-amino-1-propanol and (R)-2-amino-3-methyl-1-butanol, respectively, chromatographic separation, and mild hydrolysis. Slow syn/anti-interconversion of 5, 9, and 10 was observed at enhanced temperatures and the diastereomerization and enantiomerization processes were monitored by CD and NMR spectroscopy. The Gibbs activation energy, ΔG?, for the isomerization of 5 was determined as 103.7 (102.4) kJ/mol for the conversion of the anti-(syn-) to the syn-(anti-)isomer at 45.0 °C. Condensation of 5 with two chiral amino alcohols generates diimines that undergo quantitative asymmetric transformation of the first kind toward the thermodynamically favored (P,P,R,R)- or (M,M,S,S)-atropisomer, respectively. The incorporation of two imino alcohol units controls the outcome of this unidirectional atropisomerization, i.e. the central chirality of the amino alcohol used induces a rigid, axially chiral triaryl scaffold with perfect stereocontrol. Accordingly, the rotational energy barrier for the conversion of (M,M,S,S)-9 to its syn-isomer is significantly increased and was determined as 115.7 kJ/mol at 58.0 °C.

Synthesis and Spectroscopic Properties of the Stereoisomeric Esters from L- and D-N-Benzoylalanin and L- and D-N-Benzoylalaninol

The synthesis of the stereoisomeric esters of L- and D-N-benzoylalanine and L- and D-N-benzoylalaninol is described. - Keywords: N-Benzoylalaninyl-N'-benzoylalaninate, Stereoisomeric Esters, 1H NMR Data, 13C NMR Data, CD Data