Jms 600 instrument

The Egyptian Red Sea soft coral Nephthea sp. (voucher specimen: 399RS-9100-X19) was collected and authenticated by Dr. Montaser A. Alhammady, National Institute of Oceanography and Fisheries, Marine Biological Station, Hurghada, Egypt, from the Hurghada coast in May 2019. Four kilograms of the frozen soft coral were cut, extracted via 6 L of a mixture of 1:1 (MeOH–CH₂Cl₂), filtered, and dried under vacuum-afforded dark brown gum (167.8 g) using a rotary evaporator. The extract was further fractionated over silica gel column chromatography (6 × 120 cm) using n-hexane (100%), a step gradient of n-hexane–CH₂Cl₂, CH₂Cl₂ (100%), and CH₂Cl₂–MeOH until CH₂Cl₂–MeOH (1:1) afforded seven main fractions (NP-I to NP-VII). Fraction NP-4 (3.1 g) was subjected to silica gel column chromatography and generated three sub-fractions (NP-4A-C). The sub-fraction NP-4B (673.4 mg) was eluted by CHCl₃-MeOH (1:1) over a glass column packed with Sephadex LH-20 (3 × 120 cm) to afford compound ST-1 (181.7 mg). Compound ST-1 was analyzed via (i) NMR spectroscopic analysis (600 MHz Bruker NMR spectrometer, USA) in CD₃OD and (ii) mass spectroscopy (JEOL JMS-600 instrument (Tokyo, Japan) (Supplementary Materials Figures S1–S4). The chemical structure of ST-1 was constructed by comparison of its NMR with previously published data (Figures S1–S4) [22 (link)].

Aqueous sodium hydroxide (0.011 Mol) at 0 °C was added to a mixture of 2-acetylthiophene (1 mL, 0.0092 mol) and 2,6-difluorobenzaldehyde (1.72 g, 0.0092 mol) in ethanol. The solution was stirred for 6–8 h at room temperature. Upon completion of the reaction according to TLC, the reaction mixture was poured into ice-cold water, and the pH of the mixture was then adjusted to 6 by adding 0.01 N HCl solutions. The obtained precipitates were filtered, dried and re-crystallized from the mixture to obtain the compound. The melting points were determined in open capillary tubes and were uncorrected. The ¹H nuclear magnetic resonance (NMR) and ¹³C NMR spectra were recorded on a JNM-ECA 500 spectrophotometer (Jeol) at 500 and 125 MHz, respectively. The internal standard used for these spectra was tetramethylsilane (TMS). The IR spectra (KBr) were recorded on a Bruker-Vector 22 instrument. The molecular mass of the compounds was derived from the high-resolution mass spectral (HRMS) technique using a JEOL JMS600 instrument.