Exploring 1,3-Dioxolane Extraction of Poly(3-hydroxybutyrate) and Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) from Methylocystis hirsuta and Mixed Methanotrophic Strain: Effect of Biomass-to-Solvent Ratio and Extraction Time.

The increasing need for biodegradable polymers demands efficient and environmentally friendly extraction methods. In this study, a simple and sustainable method for extracting polyhydroxybutyrate (PHB) and poly(3-hydroxybutyrate-co-3-hydroxyvalerate (PHB-co-HV) from Methylocystis hirsuta and a mixed methanotrophic consortium with different biopolymer contents was presented. The extraction of biopolymers with 1,3-dioxolane was initially investigated by varying the biomass-to-solvent ratio (i.e., 1:2 w v-1, 1:4 w v-1, 1:6 w v-1, 1:8 w v-1 and 1:10 w v-1) and extraction time (6, 8 and 10 h) at the boiling point of the solvent and atmospheric pressure. Based on the results of the preliminary tests, and only for the most efficient biomass-to-solvent ratio, the extraction kinetics were also studied over a time interval ranging from 30 min to 6 h. For Methylocystis hirsuta, the investigation of the extraction time showed that the maximum extraction was reached after 30 min, with recovery yields of 87% and 75% and purities of 98.7% and 94% for PHB and PHB-co-HV, respectively. Similarly, the extraction of PHB and PHB-co-HV from a mixed methanotrophic strain yielded 88% w w-1 and 70% w w-1 recovery, respectively, with 98% w w-1 purity, at a biomass-to-solvent ratio of 6 in 30 min.

PDOL-Based Solid Electrolyte Toward Practical Application: Opportunities and Challenges.

Polymer solid-state lithium batteries (SSLB) are regarded as a promising energy storage technology to meet growing demand due to their high energy density and safety. Ion conductivity, interface stability and battery assembly process are still the main challenges to hurdle the commercialization of SSLB. As the main component of SSLB, poly(1,3-dioxolane) (PDOL)-based solid polymer electrolytes polymerized in-situ are becoming a promising candidate solid electrolyte, for their high ion conductivity at room temperature, good battery electrochemical performances, and simple assembly process. This review analyzes opportunities and challenges of PDOL electrolytes toward practical application for polymer SSLB. The focuses include exploring the polymerization mechanism of DOL, the performance of PDOL composite electrolytes, and the application of PDOL. Furthermore, we provide a perspective on future research directions that need to be emphasized for commercialization of PDOL-based electrolytes in SSLB. The exploration of these schemes facilitates a comprehensive and profound understanding of PDOL-based polymer electrolyte and provides new research ideas to boost them toward practical application in solid-state batteries.

[Chiral capillary gas chromatography for the separation of the enantiomers of 4-chloromethyl-2,2-dimethyl-1,3-dioxolane].

Chiral compounds play an important role in the pharmaceutical industry owing to their unique biological activities. The enantiomers must be separated because they can exhibit different pharmacological activities. Thus, the development of chiral separation methods is essential to determine the purity of enantiomers. 4-Chloromethyl-2,2-dimethyl-1,3-dioxolane is an important chiral pharmaceutical intermediate. In this context, a method based on chiral capillary gas chromatography was established for the separation and determination of the enantiomers of 4-chloromethyl-2,2-dimethyl-1,3-dioxolane. The separation of (R)- and (S)-4-chloromethyl-2,2-dimethyl-1,3-dioxolane was initially investigated using two conventional stationary-phase capillary columns: SH-I-5Sil MS and SH-WAX. The stationary phase of SH-I-5Sil MS consisted of 5% phenyl and 95% polymethylsiloxane, whereas the stationary phase of SH-WAX consisted of 100% crosslinked polyethylene glycol. Neither of the columns exhibited chiral selectivity, so they both were unable to separate the enantiomers of 4-chloromethyl-2,2-dimethyl-1,3-dioxolane. Subsequently, the separation of (R)- and (S)-4-chloromethyl-2,2-dimethyl-1,3-dioxolane was investigated using four chiral columns: Rt-bDEXm, Rt-bDEXsm, Rt-bDEXse, and InertCap CHIRAMIX. Among the chiral columns, Rt-bDEXse, which used a stationary phase composed of 2,3-di-O-ethyl-6-O-tert-butyl dimethylsilyl ß-cyclodextrin added to 14% cyanopropyl phenyl and 86% dimethyl polysiloxane, achieved the best separation of (R)- and (S)-4-chloromethyl-2,2-dimethyl-1,3-dioxolane. Thus, this column was selected as the analytical column for further method optimization. Detection was performed using a hydrogen flame ionization detector. The effects of various gas chromatographic parameters, such as linear velocity, initial column temperature, column heating rate, and solvent type, on the separation of (R)- and (S)-4-chloromethyl-2,2-dimethyl-1,3-dioxolane were investigated. The optimal chromatographic conditions included a linear velocity of 70 cm/s, an initial column temperature of 70 ℃, and a column heating rate of 2.0 ℃/min. The final column oven temperature was 150 ℃. Methanol, ethanol, ethyl acetate, n-hexane, dichloromethane, and dimethyl sulfoxide were selected as solvents. The results showed that dimethyl sulfoxide interfered with the peaks of the target compounds, whereas the other solvents had no significant effect on the peak shape and separation of (R)- and (S)-4-chloromethyl-2,2-dimethyl-1,3-dioxolane. Methanol was finally selected as the solvent in this study. Further experiments revealed that (R)- and (S)-4-chloromethyl-2,2-dimethyl-1,3-dioxolane could be rapidly separated within 10 min, with a resolution greater than 1.5. A good linear relationship was observed in the range of 0.5-50.0 mg/L, with a linear correlation coefficient greater than 0.998. The limits of detection for (R)- and (S)-4-chloromethyl-2,2-dimethyl-1,3-dioxolane were 0.07 and 0.08 mg/L, respectively, and the corresponding limits of quantification were 0.22 and 0.25 mg/L, respectively. Spiked recovery tests were performed at three spiked levels of 0.5, 2.0, and 10.0 mg/L using methanol as the blank to determine the accuracy of the proposed method. The recoveries for (R)- and (S)-4-chloromethyl-2,2-dimethyl-1,3-dioxolane were 94.0%-99.1% and 96.0%-98.8%, respectively, with relative standard deviations (RSDs) of 1.26%-4.87% and 1.51%-4.46%, respectively. The established method is efficient and reliable; thus, it can serve as a reference for the separation of the enantiomers of 4-chloromethyl-2,2-dimethyl-1,3-dioxolane. It can also potentially be applied to evaluate the enantiomeric purity of other chiral compounds in the pharmaceutical industry and produce chiral drugs and other related compounds.

In Situ Gelation of a 1,3-Dioxolane Dual-Permeable Porous Tandem Framework with Excellent Interfacial Stability to Power Long-Cycling Solid-State Lithium Metal Batteries.

Ceramic Li1.3Al0.3Ti1.7(PO4)3 (LATP) with high ionic conductivity and stability in ambient atmosphere is considered to be potent as a solid-state electrolyte of solid-state lithium metal batteries (SSLMBs), but its huge interfacial impedance with electrodes and the unwanted Ti4+-mediated reduction reaction caused by the lithium (Li) metal anode greatly limit its application in LMBs. Herein, a composite polymer electrolyte (CPET) was integrated by in situ gelation of dual-permeable 1, 3-dioxolane (DOL) in the tandem framework composed of the commercial cellulose membrane TF4030 and a porous three-dimensional (3D) skeleton-structured LATP. The in situ gelled DOL anchored in the tandem framework ensured nice interfacial contact between the as-prepared CPET and electrodes. The introduction of the porous 3D LATP endowed CPET the increased lithium-ion migration number (tLi+) of 0.70, a wide electrochemical stability window (ESW) of 4.86 V, and a high ionic conductivity of 1.16 × 10-4 S cm-1 at room temperature (RT). Meanwhile, the side reaction of the LATP/Li metal was adequately restrained by inserting TF4030 between the porous LATP and Li anode. Profiting from the superb interfacial stability and the enhanced ionic transport capacity of CPET, Li/Li batteries based on the optimal CPET (CPET2) cycled over 2000 h at 20∼30 °C smoothly. Moreover, solid-state LiFePO4 (LFP)/Li with CPET2 exhibited excellent electrochemical performance with a capacity retention ratio of 72.2% after 400 cycles at 0.5C. This work offers an integrated strategy to guide the fabrication of a highly conductive solid electrolyte and a stable interface design for high-performance SSLMBs.

High-Performance Solid Lithium Metal Batteries Enabled by LiF/LiCl/LiIn Hybrid SEI via InCl3 -Driven In Situ Polymerization of 1,3-Dioxolane.

The use of poly(1,3-dioxolane) (PDOL) electrolyte for lithium batteries has gained attention due to its high ionic conductivity, low cost, and potential for large-scale applications. However, its compatibility with Li metal needs improvement to build a stable solid electrolyte interface (SEI) toward metallic Li anode for practical lithium batteries. To address this concern, this study utilized a simple InCl3 -driven strategy for polymerizing DOL and building a stable LiF/LiCl/LiIn hybrid SEI, confirmed through X-ray photoelectron spectroscopy (XPS) and cryogenic-transmission electron microscopy (Cryo-TEM). Furthermore, density functional theory (DFT) calculations and finite element simulation (FES) verify that the hybrid SEI exhibits not only excellent electron insulating properties but also fast transport properties of Li+ . Moreover, the interfacial electric field shows an even potential distribution and larger Li+ flux, resulting in uniform dendrite-free Li deposition. The use of the LiF/LiCl/LiIn hybrid SEI in Li/Li symmetric batteries shows steady cycling for 2000 h, without experiencing a short circuit. The hybrid SEI also provided excellent rate performance and outstanding cycling stability in LiFePO4 /Li batteries, with a high specific capacity of 123.5 mAh g-1 at 10 C rate. This study contributes to the design of high-performance solid lithium metal batteries utilizing PDOL electrolytes.

Azaphilones from the Fungus Penicillium multicolor LZUC-S2 and Their Antibacterial Activity.

Two new azaphilones, penimultiones A and B, together with seven known analogs were isolated from the culture of Penicillium multicolor LZUC-S2. Their structures were elucidated by detailed spectroscopic data analysis and chemical transformation. Penimultiones A and B belong to a rare class of azaphilones possessing a 1,3-dioxolane moiety. In addition, all compounds were evaluated for their antibacterial activity against five clinically bacterial strains in vitro, and three compounds showed potent antibacterial activity with minimum inhibitory concentration (MIC) values ranging from 12.5 to 50.0 µg/mL.

Optimization for the efficient recovery of poly(3-hydroxybutyrate) using the green solvent 1,3-dioxolane.

In this study, a simple non-toxic recovery process of biodegradable poly(3-hydroxybutyrate) (PHB) using the green solvent 1,3-dioxolane and water was successfully developed. The critical parameters were optimized, and the process platform was scaled up from 2 ml to 1,000 ml for the efficient recovery of PHB. The physical parameters including continuous shaking, ultrasonication, extraction using the Soxhlet extractor, diluted 1,3-dioxolane, reused 1,3-dioxolane, and cell rupture by steam explosion prior to solvent extraction were carefully investigated. The results showed that continuous shaking played a major role in increasing the recovery efficiency during the scale-up process. The PHB extraction at 2 ml from dried cells at 80°C with 100 rpm of shaking speed for 5 h resulted in a recovery yield of 96.6 ± 0.1% with purity up to 99.1 ± 0.6% and that from wet cells under the same condition resulted in a recovery yield of 94.6 ± 4.8% and purity of 97.0 ± 0.1%. It should be noted that the PHB extracted from wet cells at room temperature with 150 rpm of shaking speed for 36 h resulted in a recovery yield of 93.5 ± 0.7% and purity of 97.7 ± 1.3% and had an MW of 3.1×105, MN of 2.7×105, and polydispersity index of 1.1. The direct scale-up process at 1,000 ml showed comparable results in purity, recovery yield, molecular weight distribution, thermal properties, and mechanical properties. The PHB extraction from dried cells gave the highest purity of 99.3 ± 0.5% and recovery of 94.0 ± 0.3%, whereas the PHB extraction from wet cells gave a purity of 90.3 ± 1.5% and recovery of 92.6 ± 1.0%. The novel recovery process showed its feasibility to be applied on an industrial scale.

Determination of potential volatile compounds in polyethylene terephthalate (PET) bottles and their short- and long-term migration into food simulants and soft drink.

Head space (HS)-GC-MS was used to analyze possible migration of volatile compounds from polyethylene terephthalate (PET) bottles for soft drinks, and a total of six compounds were identified. Next, a rapid, simple, and accurate simultaneous method was established using purge-and-trap (PT)-GC-MS, to quantify their amounts in the liquid contents after short- and long-term storage in PET bottles. Starting with brand-new PET bottles, the maximum migration of 2-methyl-1,3-dioxolane into distilled water and 50 % aqueous ethanol after 2 years at 25 °C were 2.3 and 19 ng/mL, respectively. In commercially available bottled mineral water sold inside and outside Japan, we were able to detect 2-methyl-1,3-dioxolane in the same way. While nonanal was also detected in some products, 2-methyl-1,3-dioxolane was confirmed as the main volatile compound. Finally, the human exposure to 2-methyl-1,3-dioxolane was estimated based on the per capita intake of soft drinks in Japan and the migration amount in this study.

Integrating high ionic conductive PDOL solid/gel composite electrolyte for enhancement of interface combination and lithium dentrite inhibition of solid-state lithium battery.

High interface impedance, slow ion transmission, and easy growth of lithium dendrites in solid-state lithium battery are main obstacles to its development and application. Good interface combination and compatibility between electrolyte and electrodes is an important way to solve these problems. In this work, we successfully combined a high ionic conductive polymerized 1,3-dioxolane (PDOL) solid-state electrolyte and a PDOL gel-state electrolyte to form a rigid-flexible composite structural electrolyte and realized the gelation modification of solid electrolyte/electrode interface. This "PDOL SE + PDOL Gel" composite structure not only improves the electrode/electrolyte interfacial contact, reduces the interfacial impedance, but also inhibits the growth of lithium dendrites in the interface between lithium anode and electrolyte by forming an uniform Li-Zr-O and LiF composite protection layer. This composite electrolyte has high ionic conductivity of 5.96 × 10-4 S/cm and wide electrochemical stability window of 5.0 V. The Li/PDOL SE + PDOL Gel/Li cells can be cycled stably for nearly 400 h at a current density of 1.0 mA/cm2. The assembled LiCoO2/PDOL SE + PDOL Gel/Li cells can be cycled for 250 cycles at 0.5 C with a capacity retention of 80%. This PDOL solid/gel composite electrolyte shows high promising commercial application prospect due to its high security performance, excellent interfacial properties and dendrite inhibition ability.

Self-Enhancing Gel Polymer Electrolyte by In Situ Construction for Enabling Safe Lithium Metal Battery.

Lithium metal battery (LMB) possessing a high theoretical capacity is a promising candidate of advanced energy storage devices. However, its safety and stability are challenged by lithium dendrites and the leakage of liquid electrolyte. Here, a self-enhancing gel polymer electrolyte (GPE) is created by in situ polymerizing 1,3-dioxolane (DOL) in the nanofibrous skeleton for enabling safe LMB. The nanofiber membrane possesses a better affinity with poly-DOL (PDOL) than commercial separator for constructing homogeneous GPE with enhanced ion conductivity. Furthermore, polydopamine is introduced on nanofiber membrane to form hydrogen bonding with PDOL and bis((trifluoromethyl)sulfonyl)imide anion, dramatically improving the mechanical strength, ionic conductivity, and transference number of GPE. Besides, molecular dynamic simulation is used to reveal the intrinsic factors of high ionic conductivity and reinforcing effect in the meantime. Consequently, the LiFePO4 //Li batteries using self-enhancing GPE show extraordinary cyclic stability over 800 cycles under high current density of 2 C, with a capacity decay of 0.021% per cycle, effectively suppressing the growth of lithium dendrites. This ingenious strategy is expected to manufacture advanced performance and high safety LMBs and compatible with the current battery production.

New furan derivatives from Annulohypoxylon spougei fungus.

Two new furan derivatives, annulofurans A-B (1-2), together with six known compounds were isolated from Annulohypoxylon spougei fungus. The structures were determined based on NMR and mass spectrometry data. The absolute configurations of annulofurans A-B were determined by Electronic Circular Dichroism (ECD) experiment and comparisons with the experimental ECD spectra of synthesized stereoisomers. The evaluation of the effects on radish and ruzi grass radicle elongation by the isolated compounds showed that annulofuran A affected radicle elongation of ruzi grass. The known 2-hydroxyphenylacetic acid methyl ester (7) had significant effects against both radish and ruzi grass radicle elongation, which were comparable to the commercial herbicide, glyphosate.

Acetalization of glycerol and benzaldehyde to synthesize biofuel additives using SO4 2-/CeO2-ZrO2 catalyst.

Synthesis of 1,3- dioxane and 1,3-dioxolane, using sulfated CeO2-ZrO2 catalyst for acetalization of glycerol with benzaldehyde, is the focus of present work. SO4 2-/CeO2-ZrO2 catalyst was synthesized using combustion method. Experiments were carried out to analyze the effect of various solvents (n-hexane, toluene, tert-butyl alcohol, pentanol), molar ratios (1:3, 1:5, 1:7), catalyst loadings (3 wt%, 5 wt%, 9 wt %) and temperatures (80 °C, 90 °C, 100 °C) on glycerol conversion and selectivity of the products. Selectivity of 87.20% dioxolane and 12.80% dioxane was obtained at molar ratio of 1:3, 9 wt% catalyst loading and temperature of 100 °C.Strong NH3 desorption peak from NH3-TPD study indicated the high acidic strength of sulphated catalyst. Strong surface acidity and surface porosity (observed from TEM and SEM analysis) contributed to an enhanced activity of the catalyst for glycerol acetalization reaction. The kinetics of the reaction was studied using an elementary kinetic law. A correlation coefficient of 0.98 from the selected kinetic model proved that the rate of acetalization reaction was dependent on glycerol concentration and acetal formation was instantaneous. The study demonstrated the application of an environmentally benign, inexpensive, thermally stable, active SO4 2-/CeO2-ZrO2 catalyst for glycerol acetalization reaction to synthesize 1,3-dioxolane as the desired product.

Novel Bithiophene Dimers from Echinops latifolius as Potential Antifungal and Nematicidal Agents.

Three novel dimeric bithiophenes, echinbithiophenedimers A-C (1-3), along with two known thiophenes, 4 and 5, were obtained from Echinops latifolius, and their structures were identified through extensive spectroscopic analysis and electronic circular dichroism calculations. Compounds 1-3 possessed new carbon skeletons; they are dimeric bithiophenes with 1 and 2 featuring an unprecedented 1,3-dioxolane ring system and 3 featuring an unusual 1,4-dioxane ring. These compounds are the first examples of bithiophene dimers furnished by different cyclic diethers. Dimeric bithiophenes 1-3 had good antifungal activities against five phytopathogenic fungi, and compound 3 showed excellent activity against Alternaria alternate and Pyricularia oryzae, with a minimal inhibitory concentration value of 8 µg/mL, which was close to or higher than that of carbendazim. Moreover, its effect on the mycelial morphology was observed by scanning electron microscopy. Compounds 1-3, which were demonstrated to be nonphototoxic thiophenes, exhibited better nematicidal activity than the commercial nematicide ethoprophos against Meloidogyne incognita. This study revealed that dimeric bithiophenes containing 1,3-dioxolane or 1,4-dioxane rings could be used as novel antifungal and nematicidal agents for controlling plant fungal and nematode pathogens.

Dissociative photoionization of 1,3-dioxolane: We need six channels to fit the elephant.

The dissociative photoionization of 1,3-dioxolane was studied by photoelectron photoion coincidence (PEPICO) spectroscopy in the photon energy range of 9.5-13.5 eV. Our statistical thermodynamics model shows that a total of six dissociation channels are involved in the formation of three fragment ions, namely, C3 H5 O2 + (m/z 73), C2 H5 O+ (m/z 45), and C2 H4 O+ (m/z 44), with two channels contributing to the formation of each. By comparing the results of ab initio quantum chemical calculations to the experimentally derived appearance energies of the fragment ions, the most likely mechanisms for these unimolecular dissociation reactions are proposed, including a description of the relevant parts of the potential energy surface.

Investigation on the Copolymer Electrolyte of Poly(1,3-dioxolane-co-formaldehyde).

A series of copolymers are prepared via cationic ring-opening polymerization with 1,3-dioxolane (DOL) and trioxymethylene (TOM) as monomers. The crystallization behaviors of the copolymers can be suppressed by adjusting the ratio of DOL/TOM. With LiBF4 as a source for a BF3 initiator, copolymer electrolytes (CPEs) can be prepared in situ inside cells without needing nonelectrolyte catalysts or initiators. The ionic conductivities and Li+ diffusion coefficients ( D Li + ) of the CPEs increase with a decreasing DOL/TOM ratio in a certain range. The CPE with a DOL/TOM ratio of 8/2 has the highest ionic conductivity as well as D Li + and shows excellent interfacial compatibility with lithium (Li) metal anodes. Li-Li symmetric cells can be uniformly plated/stripped for more than 1200 h. Furthermore, LiFePO4 -Li cells with 8/2-CPE display stable cycling performance for over 400 cycles. This strategy is a promising approach for the preparation of high-performance polymer electrolytes and is sure to promote their application in Li metal batteries.

(2R,3R)-1,4-Dioxa-spiro-[4.4]nonane-2,3-di-carb-oxy-lic and (2R,3R)-1,4-dioxa-spiro-[4.5]decane-2,3-di-carb-oxy-lic acids.

The title compounds, C9H12O6 and C10H14O6, were formed by careful hydrolysis of the corresponding diethyl esters. Their single crystals were grown from an ethyl acetate/hexane mixture. Crystals of both compounds have monoclinic (P21) symmetry with a single mol-ecule in the asymmetric unit. Both crystal structures are very similar and display four -CO-OH⋯O=C(OH)- hydrogen bonds, forming a two-dimensional double-layered framework.

Crystal structure of (-)-(R,E)-3-(1,3-benzodioxol-5-yl)-5-[(4S,5R)-5-hy-droxy-methyl-2,2-dimethyl-1,3-dioxolan-4-yl]-N,N-di-methyl-pent-4-enamide.

In the title compound, C20H27NO6, the amide moiety is essentially planar, with a maximum deviation of 0.073 (3) Å, and one of the N-methyl groups shows rotational disorder. The five-membered 1,3-dioxolane ring adopts an envelope form, with the C atom bonded to the olefin side chain as the flap, which deviates from the mean plane through the other four atoms by 0.564 (7) Å. The 1,3-dioxole ring fused to the benzene ring adopts a flattened envelope form, with the C atom between the two O atoms as the flap, which deviates from the mean plane through the other four atoms by 0.215 (7) Å. The C-C=C-C olefin moiety is essentially planar and makes a dihedral angle of 87.1 (3)° with the benzene ring. An intra-molecular O-H⋯O hydrogen bond supports the mol-ecular conformation, enclosing an S(11) graph-set motif. In the crystal, inter-molecular C-H⋯O hydrogen bonding links the mol-ecules into a tape running along the b axis. Furthermore, other weak C-H⋯O hydrogen bonds and a C-H⋯π inter-action connect the tapes into a sheet structure parallel to (100).

A Versatile Method for the Protection of Carbonyl Compounds by Camphor Sulfonic Acid.

BACKGROUND: Carbonyl groups are important functional groups and they play a key role in organic chemistry. This group needs to be protected in multistep synthesis against various reagents for a counter-reaction. The effort towards developing an efficient methodology for the protection of car-bonyl functional group is always a demanding reaction. The protection of carbonyl compounds for in-hibiting their chemical reactivity is an important operation in chemistry. In this paper, camphor sulfonic acid-catalysed protection of various carbonyl compounds is developed. This method is simple, envi-ronmentally friendly and yields products in high yields. METHOD: Commercially available camphor sulfonic acid is used as organo-catalyst for the protection of carbonyl functionality. This catalyst is also employed for the protection of carbonyl functionality as thi-oacetal/mixed ketal in excellent yield. The newly synthesize compounds are characterized using 1HNMR, 13C NMR and IR spectroscopy. RESULT: A diverse carbonyl functional group is protected in excellent yield under mild reaction condi-tions. CONCLUSION: We have developed an efficient organocatalysed protection method of carbonyl function-ality applicable to wide range of substrates.

Crystal structure of (-)-methyl (R,E)-4-[(2R,4R)-2-amino-2-tri-chloro-methyl-1,3-dioxolan-4-yl]-4-hy-droxy-2-methyl-but-2-enoate.

In the title compound, C10H14Cl3NO5, the five-membered dioxolane ring adopts an envelope conformation with the C atom bonded to the butenoate side chain as the flap. It deviates from the mean plane of the other atoms in the ring by 0.446 (6) Å. In the crystal, mol-ecules are connected by O-H⋯O hydrogen bonds into helical chains running along the b-axis direction. The chains are linked into a sheet structure parallel to (001) by an N-H⋯O hydrogen bond. These classical hydrogen bonds enclose an R44(24) graph-set motif in the sheet structure. Furthermore, a weak inter-molecular C-H⋯Cl inter-action expands the sheet structures into a three-dimensional network.

Design, synthesis and evaluation of 2,2-dimethyl-1,3-dioxolane derivatives as human rhinovirus 3C protease inhibitors.

The human rhinovirus (HRV) is the most significant cause of the common cold all over the world. The maturation and replication of this virus entirely depend on the activity of a virus-encoded 3C protease. Due to the high conservation among different serotypes and the minimal homology existing between 3C protease and known mammalian enzymes, 3C protease has been regarded as an attractive target for the treatment of HRV infections. In this study, we identified a novel (4R,5R)-N4-(2-((3-methoxyphenyl)amino)ethyl)-2,2-dimethyl-N5-(naphthalen-2-yl)-1,3-dioxolane-4,5-dicarboxamide (7a) to be a HRV 3C protease inhibitor via virtual screening. Further research has been focused on the design, synthesis and in vitro biological evaluation of 7a derivatives. The studies revealed that compound 7d has an IC50 value of 2.50±0.7µM against HRV 3C protease, and it thus could serve as a promising compound for the development of novel anti-rhinoviral medicines.