Octanoyl chloride

Commercial standards include (+)-catechin hydrate (≥98%), (−)-epicatechin (≥90%), rutin hydrate (≥95%) and quercetin (≥95%) were purchased from Sigma-Aldrich (Auckland, New Zealand). Acetonitrile (MeCN, HPLC grade), L-(+)-tartaric acid (reagent grade), acetone (analytical grade) and ethanol (analytical grade) were purchased from ECP (Auckland, New Zealand). Glacial acetic acid (AcOH, HPLC grade) was purchased from ThermoFisher Scientific (Auckland, New Zealand). Ultrapure water (H₂O) had resistivity of 18.2 MΩ cm and was obtained from Sartorius Arium^® Pro system. Pinot noir grape pomace (seeds, skins and stems) was industrially sourced from a New Zealand vineyard in 2015. Acylating agents (octanoyl chloride, lauroyl chloride and palmitoyl chloride) were purchased from Sigma-Aldrich (Auckland, New Zealand).

The PQS cleavage product, N-octanoylanthranilic acid, was synthesized according to the method described by Wells et al. (1952 (link)) with some modifications. Briefly, octanoyl chloride (Sigma Aldrich, Taufkirchen, Germany) was added dropwise to a solution of methyl anthranilate (Sigma Aldrich, Taufkirchen, Germany) dissolved in ethyl acetate at 0°C while stirring. Following heating to 50°C for 5 min the solution was stirred over night at room temperature resulting in a clear solution. Subsequently, this solution was successively washed with water, 1 M sodium hydroxide, 1 M hydrochloric acid and finally with brine. After drying with Na₂SO₄ the organic solvent was removed by evaporation leading to a crude oil of methyl N-octanoylanthranilate which was used without further purification. Hydrolysis of the acylated anthranilate was carried out with 0.5 M sodium hydroxide solved in ethanol. The reaction mixture was refluxed for 3 h. After cooling, the solution was acidified with 4 M hydrochloric acid and extracted two times with n-hexane. Evaporation yielded crude N-octanoylanthranilic acid which was recrystallized in n-hexane. ESI-TOF/MS for C₁₅H₂₂NO₃⁺ ([M + H]⁺): calculated m/z = 264.159; found m/z = 264.114.
CORM-2, a carbon monoxide releasing molecule, and PQS were purchased from Sigma Aldrich (Taufkirchen, Germany).

K₂[PtCl₄] (Johnson Matthey and Co.), octanoyl chloride and 2-propylpentanoyl (valproyl)chloride (Sigma-Aldrich), and all other chemicals were used without further purification. Cisplatin, cis, cis, trans-[Pt(IV)(NH₃)₂Cl₂(BA)₂] (Pt(IV)diBA), cis, cis, trans-[Pt(IV)(NH₃)₂Cl₂(HA)₂] (Pt(IV)diHA), cis, cis, trans-[Pt(IV)(NH₃)₂Cl₂(OA)₂] (Pt(IV)diOA), cis, cis, trans-[Pt(IV)(NH₃)₂Cl₂(VPA)₂] (Pt(IV)diVPA), cis, cis, trans-[Pt(IV)(NH₃)₂Cl₂AcOA] (Pt(IV)AcOA, and cis, cis, trans-[Pt(IV)(NH₃)₂Cl₂(Ac)₂] (Pt(IV)diAc) were synthesized according to published procedures^{54 (link)}. Schematic representation of the platinum compounds used in the present work is shown in Fig. 1.