Abstract
The title mol-ecule, C11H8F3NO3, adopts a cis configuration across the -C=C- double bond in the side chain and the dihedral angle between the phenyl ring and side chain is 47.35 (1)°. The -COOH group adopts a syn conformation (O=C-O-H = 0°), unlike the anti conformation observed in related maleamic acids. In the crystal, inversion dimers linked by pairs of O-H⋯O hydrogen bonds are connected via N-H⋯O hydrogen bonds and C-H⋯O inter-actions into (100) sheets, which are cross-linked by another C-H⋯O inter-action to result in a three-dimensional network. The Hirshfeld surface fingerprint plots show that the highest contribution to surface contacts arises from O⋯H/H⋯O contacts (26.5%) followed by H⋯F/F⋯H (23.4%) and H⋯H (17.3%).
Highlights
The development of pH-induced charge-conversion drugdelivery systems can help to overcome the intrinsic pH difference between tumor tissues and normal tissues or the blood stream (Ge et al, 2013)
Reactions of 2,3-dimethylmaleic anhydride (DMMA) and amino groups on the particle surface have been used to shield the positive charge of nanoparticles (Du et al, 2010)
The generated amide bond is cleavable under mildly acidic conditions but is stable at neutral or basic pH, whereas the DMMA-decorated nanoparticles are inert under physiological conditions
Summary
The development of pH-induced charge-conversion drugdelivery systems can help to overcome the intrinsic pH difference between tumor tissues (pH 6.5–6.8) and normal tissues or the blood stream (pH 7.2–7.4) (Ge et al, 2013). Reactions of 2,3-dimethylmaleic anhydride (DMMA) and amino groups on the particle surface have been used to shield the positive charge of nanoparticles (Du et al, 2010). The generated amide bond is cleavable under mildly acidic conditions but is stable at neutral or basic pH, whereas the DMMA-decorated nanoparticles are inert under physiological conditions. After accumulating into the acidic tumor tissue through the enhanced permeation and retention (EPR) effect, the amide bond slowly cleaves and exposes the positive charge, which eventually promotes cell internalization. The hydrolysis profiles of mono- or di-substituted maleamic acids were studied by the same authors to elucidate their hydrolysis selectivity towards various physiologically available pH values (Su et al, 2017). Symmetry codes: (i) x; Ày þ 32; z À 12; (ii) Àx þ 1; Ày þ 2; Àz þ 2; (iii) Àx þ 1; y þ 12; Àz þ 32
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