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Hatäda, Koichi; Shimizu, Shin-ichi; Yuki, Heimei; Harris, William J.; Vogl, Otto

doi:10.1007/bf00255417

Cited by 5 publications

(13 citation statements)

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“…IV-Formyl-L-alanine Ethyl Ester (la). L-Alanine (4j) was esterified with ethanol and dry HC1, according to a standard procedure.29,30 Subsequent reaction with formic acid, sodium formate, and acetic anhydride31 afforded la as a colorless liquid in quantitative yield: [ :]21578 -69.0°(c 4, ethanol); IR (neat) 1740 (CO), 1675 (NCO) cm"1; NMR (CDC13) 8.24 (s, 1 H, CHO), 7.75 (br, 1 , NH), 4.61 (m, 1 H, CH), 4.22 (q, 2 H, CH2), 1.43 (d, 3 H, CHS), 1.25 (t, 3 H, CH3).…”

Section: Methodsmentioning

confidence: 99%

“…Found: C, 56.14; H, 7.22; N, 10.95; O, 25.70. (S)-2-Aminopropanol (L-Alaninol (5j)). A'-Benzoyl-L-alanine and TV-benzoyl-L-alanine methyl ester were prepared starting from L-alanine (4j) according to standard procedures.29,30 AI-Benzyl-L-alaninol was prepared from the above ester with an excess of LiAlH4 in boiling diethyl ether.29,32 After hydrogenolysis in water-ethanol (1:4 (v/v)) at 60 °C, compound 5j was isolated as its HC1 salt in an overall yield of 90%: [a]22D +19.8°(c 2.5, methanol); NMR (CD3OD) 4.8 (br, 4 H, NHS+ and OH), 3.5-3.9 (m, 3 H, CH2 and CH), 1.30 (d, 3 H, CH3).…”

Section: Methodsmentioning

confidence: 99%

“…The mixture was kept at 50 °C during 24 h. The excess of volatile reagents was removed at reduced pressure. Compound lb was obtained as a yellow syrup in a quantitative yield: [ct]22578 -39.9°(c 2.5, CHC13); IR (neat) 1735 (OCO), 1675 (NCO) cm*1; NMR (CDC13) 8.15 (s, 1 H, CHO), 7.15 (br, 1 , NH), 4.33 (m, 1 H, CH), 4.04 (m, 2 H, CH20), 2.05 (s, 3 H, COCH3), 1.18 (d, 3 H, CH3). Another route to lb started from a sample of commercially available optically pure (S)-2-aminopropanol.…”

Section: (S)-n-formyl-o-acetyl-2-aminopropanol (Lb) Alcohol 6jmentioning

confidence: 99%

“…There is indirect evidence that polychloral prepared from chloral with a chiral initiator forms a stable helix with preference of one helical screw sense over the other. 4 It has been shown that triphenylmethyl methacrylate, when polymerized by chiral anionic catalysts, yields an isotactic, optically active polymer. 5 The optical activity is attributed to the presence of a rigid helix, which is stable because of the bulky triphenylmethyl ester functions.…”

Section: Introductionmentioning

confidence: 99%

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Helical configuration of poly(iminomethylenes). Synthesis and CD spectra of polymers derived from optically active isocyanides

Beijnen¹,

Nolte²,

Naaktgeboren³

et al. 1983

Macromolecules

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Each of nine chiral isocyanides, R*-N=C, in enantiomerically pure or almost pure form, is polymerized to the corresponding poly(iminomethylene), [R*-N=C<]n. The group R* either contains at least one substituent (carboxylic ester, phenyl, phosphinyl) or is unsaturated (C=C, C=C). The polymers are of the rigid-rod type with a helical main chain of carbon atoms. Because of the chirality of R*-N=C either the P or the M helix is preferentially formed. CD spectra and optical rotation at 578 nm are determined and compared with those of the model compounds R*-N=CH(i-C4H9) and the monomers. This comparison and earlier calculations on [i-C4H9-N=C<]n allowed the assignment to each polymer of the excess screw sense. The screw sense is also theoretically predicted by two approaches, a thermodynamic and a kinetic one. The latter approach gives an appreciably better fit with the experimental results.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: (S)-n-formyl-o-acetyl-2-aminopropanol (Lb) Alcohol 6jmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Helical configuration of poly(iminomethylenes). Synthesis and CD spectra of polymers derived from optically active isocyanides

Beijnen¹,

Nolte²,

Naaktgeboren³

et al. 1983

Macromolecules

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“…Chiral PC could also be prepared by initiating chloral polymerization with an achiral anion, but a chiral phosphonium counterion. To demonstrate the chirality of the PC, a column filled with chiral PC separated a mixture of isotactic polymers of R ‐(+)‐ and S ‐(−)‐α‐methylbenzyl methacrylate 34…”

Section: Addition Polymers Of Aldehydesmentioning

confidence: 99%

Effect of temperature and span series surfactant on the structure of polysulfone membranes

Tsai

Ruaan

Wang

et al. 2002

J of Applied Polymer Sci

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A macrovoid structure was found in polysulfone membranes formed by the wet-inversion method using N-methylpyrrolidinone (NMP) and water as the solvent/nonsolvent pair. The addition of Span series surfactants in the casting solution was found to inhibit the macrovoid formation. Sorbitan monooleate (Span-80) was more effective in inhibiting macrovoids than was sorbitan monolaurate (Span-20). The phenomenon of macrovoid suppression became more prominent at higher temperature. The cloud-point shift might account for the temperature effect. But there was no simple explanation for the effect caused by Span-80. The cloud-point position, the demixing rate, and the viscosity of the casting solution were measured. None of them could explain the effect of macrovoid inhibition by the addition of Span-80. However, the penetration test indicated that the penetration of a nonsolvent into a surfactant-free casting solution was caused by a convective flow, but that into Span-80 was through diffusion. It was found that the retardation of nonsolvent penetration was the major cause of macrovoid inhibition.

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Synthetic Helical Polymers: Conformation and Function

2001

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I. Introduction 4013 II. Helical Polymers 4015 A. Polyolefins 4015 B. Polymethacrylate and Related Polymers 4016 1. Poly(triphenylmethyl methacrylate) 4016 2. Poly(triphenylmethyl methacrylate) Analogues: Anionic Polymerization 4017 3. Poly(triphenylmethyl methacrylate) Analogues: Free-Radical Polymerization 4018 4. Polymers of Other Acrylic Monomers 4022 C. Miscellaneous Vinyl Polymers 4023 D. Polyaldehydes 4023 1. Polychloral and Related Polymers 4023 2. Other Polyaldehydes 4024 E. Polyisocyanides 4024 1. Polymers of Monoisocyanides 4024 2. Polymers of Diisocyanides 4025 F. Polyisocyanates and Related Polymers 4025 1. Polyisocyanates 4025 2. Polycarbodiimides 4027 G. Polyacetylene Derivatives and Related Polymers 4027 1. Polyacetylene Derivatives 4027 2. Polyphosphazene 4029 H. Poly(aryleneethynylene)s 4029 I. Polyarylenes 4030 J. Si-Containing Polymers 4031 1. Polysilanes 4031 2. Polysiloxane 4032 K. Other Types of Polymers 4032 1. Miscellaneous Examples 4032 2. Mimics and Analogues of Biopolymers 4033 III. Helical Polymeric Complexes and Aggregates 4033 A. Helicates 4033 B. Helical Aggregates 4033 IV. Summary and Outlook 4034 V. Acknowledgments 4034 VI. References 4034

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Correction

Cited by 5 publications

References 0 publications

Helical configuration of poly(iminomethylenes). Synthesis and CD spectra of polymers derived from optically active isocyanides

Helical configuration of poly(iminomethylenes). Synthesis and CD spectra of polymers derived from optically active isocyanides

Effect of temperature and span series surfactant on the structure of polysulfone membranes

Synthetic Helical Polymers: Conformation and Function

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