SIDE CHAIN LIQUID CRYSTALLINE POLYSILOXANES CONTAINING CROWN ETHER AND BENZYL ETHER MOIETIES

Two kinds of side chain liquid crystalline polysiloxanes containing crown ether and benzyl ether were synthesized and characterized by optical polarization microscopy. Both the monomeric liquid crystals and polymeric liquid crystals show smectic phases.

Hydrogenation of Alkenes with NaBH4, CH3CO2H, Pd/C in the Presence of O- and N-Benzyl Functions

NaBH4, CH3CO2H, Pd/C has been described as an effective reagent system to hydrogenate alkenes. Here, we show that the hydrogenation occurs chemoselectively, making it possible to hydrogenate alkenes under Pd/C catalysis with hydrogen created in situ without O- or N-debenzylation.

A SYNTHESIS OF TETRAMETHYL ETHER OFROSMARINIC ACID BENZYL ESTER

A rosmarinic acid derivative, tetramethyl ether of rosmarinic acid benzyl ester, was synthesized. This is the first report of building this structural skeleton.

The Synthesis of Hexamethyl Ether of Salvianolic Acid A Benzyl Ester

A salvianolic acid A derivative, hexamethyl ether of salvianolic acid A benzyl ester, was synthesized in fourteen steps. The overall yield was 3.4 parts per thousand. The compound was identified by (1)HNMR and MS. This is the first report of building this structural skeleton.

SYNTHESIS AND CHARACTERIZATION OF SIDE CHAIN LIQUID CRYSTATALLINE POLYSILOXANES CONTAINING BENZYL ETHER LINKING UNITS

Side chain liquid crystalline polysiloxanes containing benzyl ether linkingunits were synthesized by the hydrosilylation of poly (methylhydrosiloxane) with a series of4-(4-alkoxybenzyloxy)-4'-allyloxybiphenyl monomers [4-(4-methoxybenzyloxy )-4'-allyloxy-biphenyl(M_1), 4-(4-ethoxybenzyloxy)-4'-allyloxybiphenyl (M_2), 4-(4-propoxybenzyloxy)-4'-allyloxybiphenyl (M_3), 4-(4-butoxybenzyloxy)-4'-allylox(M_4), 4-(4-pentoxy-benzyloxy)-4'-allyloxybiphenyl (M_5), 4-benzyloxy-4'-allyloxybiphenyl (M_6)]. The phasebehavior of monomeric and polymeric liquid crystals was characterized by differential scan-ning calorimetry and optical polarization microscopy where the groups are ranged frommethoxy to pentoxy Both the monomeric and polymeric liquid crystals exhibit 1iquidcrystal behaviors.

Synthesis and Characterization of Side-Chain Liquid Crystalline Polysiloxanes

Side chain liquid crystalline golysiloxanes conta ing biphenyl and benzyl ether mesogen were synthesized by the hydrosilation of poly(methylhydrcsiloxane) with 4-(4-allyloxybenzytoxy)-4'- methoxybiphenyl(M_1),4-(4-allyloxybenzyloxy)-4'-ethoxybiphenyl(M_2),4-(4-allyloxybenzyloxy)-4'- propoxybiphenyl(M_3),4-(4-allyloxybenzyloxy)-4'-butoxybiphenyl(M_4),4-(4-allyloxybenzyloxy)-4'- pentyloxybiphenyl(M_5).The phase behavior of monomeric and polymeric liquid crystals was chararcterized by differential scanning calorimetry and optical polarization microscopy.Both the monomeric and polymeric liquid crystals exhibit liquid crystal behaviors.

Iron-mediated cross dehydrogenative coupling(CDC) of terminal alkynes with benzylic ethers and alkanes

Iron-mediated sp-sp3 C-C bond formation through the cross dehydrogenative coupling(CDC) of terminal alkynes with benzylic ethers or alkanes has been developed.The inexpensive iron salt is used as the catalyst to make this transformation environmentally benign.Iron-mediated sp-sp3 C-C bond formation through the cross dehydrogenative coupling(CDC) of terminal alkynes with benzylic ethers or alkanes has been developed.The inexpensive iron salt is used as the catalyst to make this transformation environmentally benign.

New clues concerning pigment biosynthesis in green colored fiber provided by proteomics-based analysis

To separate the proteins related to pigment synthesis in green colored fiber （GCF）, we performed a comparative proteomic analysis to identify the differentially expressed proteins between green cotton fiber and a white near-isogenic line （NIL）. One differential spot identified as phenylocumaran benzylic ether redutase-like protein （PCBER） was expressed only in GCF, but was not found in white colored fiber （WCF） at any time points. Since PCBER was a key enzyme in lignans biosynthesis, total lignans were extracted from GCF and WCF and their content was determined by using a chromotropic acid spectrophotometric method. The results showed that total lignans content in GCF was significantly higher than that in WCF. The qPCR analysis for two PLR genes associated with lignans biosynthesis showed that the expression level of two genes was much higher in GCF than that in WCF at 24 and 27 days post anthesis （DPA）, which may be responsible for the higher lignans content in GCF. Our study suggested that PCBER and lignans may be responsible for the color difference between GCF and WCF. Additionally, p-dimethylaminocinnamaldehyde （DMACA） staining demonstrated that the pigment in GCF was not proanthocyanidins, and was different from that in brown colored fiber （BCF）. This study provided new clues for uncovering the molecular mechanisms related to pigment biosynthesis in GCF.

A Review on the Structure and Biodegradation of Cellulose-Lignin Complexes

Cellulose is the most abundant organic macromolecule in nature and is renewable,degradable,and biocompatible.The structure of native cellulose has not yet been completely elucidated.Part of cellulose is tightly combined with lignin macromolecules through chemical bonds to form cellulose-lignin complexes(CLC).The existence of the CLC structure inhibits the complete separation of cellulose from lignocellulosic material,which not only increases the consumption of chemicals in the cooking process and causes environmental pollution,but also makes the cellulose subject to certain degradation during the deep delignification process.Therefore,elucidation of the relationship between the cellulose-lignin connection structure and performance is of great significance for efficient separation of cellulose.This article reviews the current research status of CLC and discusses the research progress regarding its biodegradation characteristics.

Hydrolysis kinetics of benzyl phenyl ether in high temperature liquid water

The application of high temperature liquid water（HTLW） to decomposition of lignin as efficient and green solution for phenolic compounds recovery was studied.Benzyl phenyl ether（BPE）,the lignin model compound,was treated at temperatures ranging from 220 to 250℃.BPE undergo hydrolysis in HTLW,and main products were phenol and benzyl alcohol with the minimum selectivities of 75.7%and 82.8%,respectively.Lower temperature led to higher selectivity in 220-250℃temperature range.The kinetics on BPE hydrolysis was studied and the activation energy was determined as 150.3±12.5 kJ/mol with the first-order kinetic equations.Based on products distribution,the reaction mechanism for decomposition of benzyl phenyl ether was proposed.The investigated process provides insights into the design of a commercial method for utilization of lignin.

Studies on macrocyclic diterpenoids Ⅴ.Synthesis of(±)-sarcophytol-A benzyl ether

The title compound,sarcophytol-A benzyl ether has been synthesized through 13 steps by employing acetone and geraniol as starting materials.The key steps in the synthesis were double bond migration reaction of allylic alcohols 5 and 6,phase transfer catalytic coupling (PTC)reaction of Ⅱ with 7 and the cyclization reaction of dicarbonyl acyclic precursor induced by TiCl_3-AlCl_3(3:1)/Zn-Cu system.