Cocrystal Phenomena of DABCO with Phenol Derivatives

It has been reported that 1,4-diazabicyclo[2,2,2] octane(DABCO) can form complexed crystals with lithium alkals. Our experimental results show that DABCO can also form cocrystals with phenol derivatives such as phenol(2), o-cresol(3), m-cresol(4), p-cresol(5), p-chlorophenol(6), and p-nitrophenol(7). The separa-

Isolation and Neuroprotective Activity of Phenolic Derivatives from the Marine-Derived Fungus Penicillium janthinellum

A new phenolic compound, 6-(2-acetyl-3,5-dihydroxybenzyl)-4-hydroxy-3-methyl-2H-pyran-2-one(1), along with other six known phenolic derivatives(2-7), were isolated from the mangrove rhizosphere fungus Penicillium janthinellum HK1-6 cultured in potato dextrose broth medium containing 30 g L^(-1) of natural sea salt. The structure of the new compound(1) was elucidated by comprehensive analysis of spectroscopic data including 1D and 2D NMR spectra. The proposed biosynthetic pathway of compound 1 was also studied in this research. Interestingly, a brominated phenolic derivative, aryl bromide(compound 8), was obtained from this fungal strain cultured in medium containing 30 g L^-1 of NaBr instead of natural sea salt. Compound 8 is proposed as a new natural product and formed through bromination of compound 7 when the fungus was cultured with NaBr. The neuroprotective effect of compound 1 on oxygen-glucose deprivation(OGD)-induced injury was investigated in rat spinal cord astrocytes. MTT assay demonstrated that compound 1 can attenuate OGD-induced cell viability loss in rat spinal cord astrocytes.

A NEW METHOD FOR THE PREPARATION OF PHENOLS AND ITS DERIVATIVES

a-Oxo ketene dithioacetals 2 via 1,2-nucleophilie addition by methallyl magnesius chloride afforded corresponding alcohols (3). Treated with water or methanol and catalyzed by Lewis acid, the alcohols 3 were converted regiospecifical ly to substituted phenols 5' or related phenol methyl ethers 5 respectively. This reaction is a novel approach to the synthesis of phenols and their derivatives starting from non-aromatic precursors.

Deaggregation Behavior of the Phenol Derivatives

Aggregation and deaggregation behaviors of the phenol derivatives with a branched hydrocarbon chain have been studied in the CH3OH and buffer solution. Combination with the aggregation number measurement and the cell adhesion experiment, the structure effect on the deaggregating abilities of the target molecules are discussed. The results indicate that 2-phytyl-4-methoxylphenol （11） is the most effective deaggregator in the system studied.

A Structure and Antioxidant Activity Study of Paracetamol and Salicylic Acid

The paracetamol has more antioxidant properties than the salicylic acid on the several oxidative stress-forced models and one possible mechanism is due to electron or hydrogen transfer by the evaluated hydroxyl radicals. The antioxidant mechanism for the compounds studied here was performed by molecular modeling using quantum chemical calculations at the B3LYP level of theory. Our results show that the paracetamol has more antioxidant properties than the salicylic acid in experimental and theoretical studies. The theoretical mechanism show that the hydrogen transfer is more favorable than the electron transfer. From the study it was concluded that the electron abstraction for paracetamol is more favored than salicylic acid.

Bio-renewable polymers based on lignin-derived phenol monomers:Synthesis,applications,and perspectives

In recent decades,the continuous depletion of fossil fuels and the increasingly serious environmental issue have aroused wide attention on the development of biopolymers based on renewable biomass.Lignin is the second most abundant organic bio-based macromolecule second to cellulose,and it can be widely found in plants.Furthermore,various phenol derivatives can be obtained by their depolymerization processes.The development of bio-renewable polymeric materials originating from lignin-derivative phenol monomers,such as vanillin,syringaldehyde,eugenol,vanillyl alcohol,vanillic acid,and ferulic acid,will not only valorize the bio-sourced materials but also effectively reduce petroleum resource consumption and mitigate the environmental pollution.Therefore,an updated overview of the synthesis processes of these bio-based polymers developed in the past decade,which includes both thermosets and thermoplastics such as epoxy,phenolic,polyimine,polybenzoxazine,polyurethane,and polyesters,are elucidated.In addition,the applications of these bio-based polymers and their composites in flame-retarded materials,degradable and reprocessable materials,dielectric materials,optoelectronic materials,as well as smart responsive materials are also intensively discussed.In line with the gradual development of synthesis technologies,we believe that derivatives of lignin will turn into one of the most promising materials to be considered for the preparation of high-performance and functional bio-based polymer materials.

Chemical constituents from Qianliang tea

Ten compounds were isolated from Qianliang tea, a kind of dark tea fully fermented from the leaves of Camellia sinensis （L.） O. Kuntze vat. sinensis, and identified .as N-（2-hydroxyphenyl）-2-pyrrolidinone （1）, p-hydroxyacetophenone （2）, salicifoliol （3）, （-）-3-hydroxy-/q-ionone （4）, p-hydroxy ethyl ciunamate （5）, ethyl 4-（sulfooxy）benzoate （6）, （＋）-matairesinol （7）, （-）-pinoresinol （8）, （＋）-lirioresinol-A （9）, and caffeine （10）, among which compound 1 was isolated as a new natural product, and compound 6 was isolated from Theaceae family for the first time. Compounds 3, 4, 5, 7, 8, and 9 were isolated from this species for the first time.