A General Method for the Preparation of Chiral TREN Derivatives

Abstract

A general procedure for the preparation of C 3 -symmetric TREN derivatives with backbone chirality has been developed. Stereo-and regioselective ring opening by ammonia of (S)-N-tosyl-2-isopropylaziridine, obtained starting from either the corresponding amino alcohol or amino acid, followed by deprotection of the amino groups afforded the par-

Circularly Polarized Luminescence in Enantiopure Europium and Terbium Complexes with Modular, All-Oxygen Donor Ligands

“…Its synthesis started from known, selectively at the primary amines protected bis(trifluoroacetamide) 7 ,22 which already has two propylene-C 3 units attached to the central ethylene moiety. Two-fold regioselective ring-opening of ( R )- N -tosyl-2-ethylaziridine ( 8 )23 by the two secondary amines of 7 gave the unsymmetrically protected hexamine 9 . Simultaneous removal of the tosyl- and trifluoroacetamide-protecting groups by a mixture of conc.…”

“…and ( R )- N -tosyl-2-ethylaziridine23 ( 8 ) (13.74 g, 61.0 mmol, 2.3 equivs.) were dissolved in dry benzene (150 mL) and the solution was heated under reflux for 43 h. After cooling down to ambient temperature, the solvent was removed under reduced pressure and the yellow oil was purified by column chromatography (SiO 2 , gradient: CH 2 Cl 2 /MeOH 100:1 to CH 2 Cl 2 /MeOH 50:1).…”

Synthesis and biological evaluation of reversible inhibitors of IdeS, a bacterial cysteine protease and virulence determinant

“…The ditosylated product (15) was further reacted with either sodium azide or sodium cyanide in DMSO to give compounds 16 and 17, respectively, in high yields (97% and 93%, respectively). The nitrile (17) was converted to the corresponding aldehyde (18) in the same manner as described above, again in a low yield (26%). Finally, the Boc-protected alcohol (14), azide (16) and nitrile (17) derivatives were deprotected by TFA in dichloromethane to give 19-21 in the yields 78%, 80% and 93%, respectively.…”

“…The nitrile (17) was converted to the corresponding aldehyde (18) in the same manner as described above, again in a low yield (26%). Finally, the Boc-protected alcohol (14), azide (16) and nitrile (17) derivatives were deprotected by TFA in dichloromethane to give 19-21 in the yields 78%, 80% and 93%, respectively. Unfortunately, the unprotected aldehyde derivative could not be isolated with a satisfying purity.…”

“…Aziridine formation has been reported earlier, either when treating amino alcohols under Mitsunobu conditions or the corresponding mesylate or tosylate using Et 3 N, KOH or K 2 CO 3 as the base. 17,18 Instead, ditosylated intermediates (5a-c) were synthesized using two equivalents of tosylchloride in reactions with the amino alcohols (3a-c) to afford products in low to moderate yields (43-63%). Pyridine was used as base and no aziridine formation was detected.…”