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Abstract The syntheses are reported of Nϵ‐(2,2,2‐trifluoroethyl)‐D,L‐lysine (tFK) and Nζ‐(2,2,2‐trifluoroethyl)‐D,L‐homolysine (tFK+1) from amino alcohols HO−(CH2)n−NH2. The syntheses involve reductive amination, Appel bromination, and the stereoselective bond formation between Cα of the amino acid and the fluorinated alkyl chain in the Schöllkopf bislactim amino acid synthesis. The methyl esters of the fluorinated amino acids are the relevant substrates for oligopeptide synthesis. With theR‐Schöllkopf reagent, we stereoselectively generated methyl Nϵ‐boc‐Nϵ‐(2,2,2‐trifluoroethyl)‐L‐lysinate and methyl Nζ‐boc‐Nζ‐(2,2,2‐trifluoroethyl)‐L‐homolysinate. Products and intermediates were characterized by 1H NMR, 13C NMR, COSY, HSQC, and LCMS. A variety of N‐functionality may be introduced by reacting hemiacetals with different appendages. This fluorine modification reduces the sidechain N‐basicity by combined ‐I effect of the three fluorines. This effect increases the [amine]/[ammonium ion] ratio of the sidechain amine in lysine to facilitate carbamylation at lower pH conditions.
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Synthesis of N ‐Substituted Maleimides and Poly(styrene‐ co ‐ N ‐maleimide) Copolymers and Their Potential Application as Photoresists
Abstract Poly(styrene‐co‐N‐maleimide) copolymers bearingtert‐butoxycarbonyl (t‐BOC)‐protected amine groups attached to side chains of varying lengths are synthesized via activators regenerated by electron transfer atom transfer radical polymerization (ARGET‐ATRP) and investigated from the perspective of photoresist applications. The length of the alkyl substituents enables control of thermal properties as well as hydrophobicity, which are critically important for resist processing. Removal of the acid labilet‐BOC group during deep‐UV (DUV)exposure shifts solubility in the exposed areas and well‐defined line space patterns of 1 µm are obtained for the selected copolymers. The correlation between glass transition temperature (Tg) and solubility contrast determines the lithographic performance where the copolymers with shorter alkyl chains exhibit promising results.
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- Award ID(s):
- 1719875
- PAR ID:
- 10370600
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Macromolecular Chemistry and Physics
- Volume:
- 224
- Issue:
- 1
- ISSN:
- 1022-1352
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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