Synthesis and viscosity behavior of poly(γ‐p‐biphenylmethyl‐L‐glutamate) in benzene/dichloroacetic acid mixtures, a comparison with poly(γ‐benzyl‐L‐glutamate)

Abstract

SUMMARY:The synthesis of poly(y-p-biphenylmethyl-L-glutamate), PBPLG, (poly{ L-imino-1 -[2-(4-biphenylylmethoxycarbonyl)ethyl]-2-oxoethylene}), (Id) is described. The viscosity behavior of this polymer in benzene/dichloroacetic acid mixtures (~= 0 , 2 . 1 0 -~-1,4. g/cm3) at 25°C is investigated. The results are compared with measurements on poly(ybenzyl-L-glutamate), PBLG, (poly [ L-imino-1 -(2-benzyloxycarbonylethyl)-2-oxoethylene]), (lc) under the same conditions. A transition from a rigid hydrogen bonded helix to a random solvated coil occurs in two stages for both: PBPLG (first stage 0-55%, second stage 55-100% dichloroacetic acid) and PBLG (first stage 0-

Poly‐γ‐p‐Biphenylmethyl‐Glutamate as Enantiodifferentiating Alignment Medium for NMR Spectroscopy with Temperature‐Tunable Properties

“…Synthesis of the polymer PBPMLG Poly‐ l ‐ 1 was achieved according to a literature protocol in a six‐step synthesis with a slightly modified procedure based on our experience with PBLG . We used the same protocol (see Scheme ) for the hitherto unknown Poly‐ d ‐1 starting from d ‐glutamic acid 2 using alcoholysis of the N ‐phthaloyl‐protected cyclic anhydride 3 of glutamic acid followed by removal of the protection group for a convenient access to the desired glutamic acid ester 5 .…”

“…Synthesis and characterisation of PBPMG Synthesis of the polymer PBPMLG Poly-l-1 was achieved according to al iterature [15] protocol in as ix-step synthesis with a slightly modified procedure based on our experience with PBLG. [5d] We used the same protocol (see Scheme 1) for the hitherto unknown Poly-d-1 starting from d-glutamic acid 2 using alcoholysis of the N-phthaloyl-protected cyclic anhydride 3 of glutamic acid followed by removal of the protection group for ac onvenienta ccess to the desired glutamic acid ester 5.T he corresponding N-carboxyanhydride (NCA) 6 was synthesised with phosgene (as 20 %s olution in toluene), yielding highly pure monomer 6.T he ring-opening polymerisation was then successfully carriedo ut with triethylamine as initiator (Scheme1,f or experimental details see the Supporting Information).…”

“…PBPMLG was first synthesised by Feijen et al. and investigated towards its stability and viscosity behaviour with regard to the transition between helix and random coil in the presence of dichloroacetic acid . Although the additional p ‐phenyl substituent, as compared to PBLG, decreases the stability of the helix, PBPMLG still forms a stable helix in helicogenic solvents.…”

“…PBPMLG was first synthesised by Feijen et al and investigated towards its stabilitya nd viscosity behaviour with regard to the transition between helix and random coil in the presence of dichloroacetic acid. [15] Althought he additional p-phenyl substituent, as compared to PBLG, decreases the stability of the helix, PBPMLGs till forms as table helix in helicogenic solvents. More interestingly,P BPMLG exhibits as ignificant temperaturedependent effect on its opticalb ehaviour.D ilute solutions of the polymeri ns everal solvents show as udden change of the specific rotationb elow 273 K. [16,17] The corresponding circular dichroism (CD) spectrac onfirm that the a-helical structure remains,w hile as trong CD band associated with the biphenyl chromophore emerges.…”

Synthesis and Estimation of Poly[γ-(4-alkoxyphenyl)-benzyl-L-glutamate]s

“…Another procedure to obtain }'-esters Lglutamate has been reported by Yamamoto et al 13 and Feijen et al, 14 who synthesized the esters by the addition of alcohol to Nphthaloyl-L-glutamic anhydride.…”