Acryloyl chloride

L-ornithine monohydrochloride salt (99%), L-cystine (98.5%), acryloyl chloride (96%), copper(II) nitrate trihydrate (98%), N,N,N′,N′-tetramethylethylenediamine (TEMED), and ammonium persulfate (APS) were purchased from Sigma-Aldrich, Poznań, Poland. Sodium hydroxide (NaOH, 99%) and hydrochloric acid (HCl, 35-38%) were purchased from POCh. Lead(II) nitrate (≥99%) and silver nitrate (99%) were purchased from Honeywell. Ultrapure nitric acid (67%) was purchased from Merck, Poznań, Poland. All chemicals were utilized in their received form without any further purification. Solutions were prepared using high-purity water obtained from a Milli-Q Plus/Millipore purification system, Poznań, Poland, ensuring a water conductivity of 0.056 μS•cm -1 . The N-δ-acryloyl ornithine monomer (AcOrn) and the N,N'bisacryloylcystine cross-linker (BISS) were synthesized following established methods described in previous research [11] (link). In the context of N-δ-acryloyl ornithine, the procedure involved adding ornithine monohydrochloride to a NaOH solution. A solution with CuSO 4 •5H 2 O was introduced, resulting in a deeply blue solution, which was then cooled to 10 °C. Acryloyl chloride and NaOH were gradually added dropwise while maintaining the pH between 9 and 10. After completion, the reaction mixture was stirred overnight at room temperature. The blue precipitate formed was filtered, washed, and dried, resulting in the N-δ-acryloyl ornithine-copper complex. Thioacetamide was introduced to a powdered suspension of the complex in water, stirred for 20 min, and the pH was adjusted to 9. This led to the formation of a copper sulfide precipitate, which was filtered, yielding a colorless filtrate. After evaporating the water, a residue was dissolved in a mixture of MeOH and CF 3 COOH. Et 2 O was used for precipitation, and the crude product underwent recrystallization with MeOH and Et 2 O. To synthesize N,N'-bisacryloylcystine, the following procedure was utilized: a solution containing sodium hydroxide and cystine in methanol underwent stirring, and acryloyl chloride was cautiously added dropwise at 0 °C. The resultant solution was further stirred at ambient temperature. After a duration of approximately 4 h, the reaction mixture was subjected to filtration using a celite pad. The filtrate was then gradually introduced dropwise into vigorously stirred cold diethyl ether. The resulting suspended solid was separated through filtration, treated with diethyl ether washing, and subsequently dried using high vacuum conditions within the range of 30-45 °C. The analysis based on sulfur content from combustion analysis revealed the presence of approximately 65% of the disodium salt of N,N′-bisacryloylcystine in the powder. The successful synthesis of N-δ-acryloyl ornithine and N,N'-bisacryloyl cysteine was confirmed using 1 H NMR, 13 C NMR, and mass spectroscopy techniques.