bluuebunny/crossref_metadata_2025 huggingface dataset:
Determination of the Molecular Weight and Particle Radius of Gelatin Micelles by Sedimentation and Optical Mixing Spectroscopy
Authors: Hwang Jeng‐Shung , Gi Hung‐Jang , Chen Shou‐Nan
Published: June 2015

Micelles formed from gelatin solutions were studied by sedimentation and optical mixing spectroscopy (OMS). We sampled gelatin solutions at various centrifugal speeds. Single exponential autocorrelation functions of the gelatin solutions were measured at 27°C and at 90° scattering angle by OMS. Calculation of the diffusion coefficient D from the measured autocorrelation function of scattered light has been carried out in this studied. A calculation of the micellar radius from the Stokes‐Einstein equation was carried out. We also calculated the sedimentation coefficient and molecular weight of gelatin micelles and found that the polydisperse gelatin micelles were formed at 50mg/mL.
Collisional Deactivation of K(7s2S) and K(5d2D) by No
Authors: Chang Min‐Lung , Huang Jui‐Tsen , Lin King‐Chuen
Published: June 2015

Radiative lifetimes and total deactivation cross sections of K(72S) and K(52D) by collision with NO are studied. The K atomic vapor in either the 72S or the 52D state was prepared by two‐ photon absorption using a dye laser. The decay signal of the time‐resolved fluorescence from the 72S – 42P1/2 or 52D – 42P3/2 transition was then monitored. Based on a Stern‐Volmer analysis, the radiative lifetimes are 155 ±8 ns and 561 ± 18 ns for the K(72S) and K(52D) states, respectively. The total deactivation cross sections are 88 ±1Å2 and 70 ±2Å2 for the K(72S)‐NO and K(52D)‐NO collisions, respectively. In the absence of NO collisions the radiative lifetimes obtained in this work show excellent agreement with those previously reported. The quenching cross sections for NO have been measured for the first time, and have values in a reasonable range, when compared with Na‐N2 collisions.
Two‐Photon Spectroscopy of Acetylene ‐ Photodissociation Processes at 9‐10 eV Energy Levels
Authors: Lee Ing‐Fang , Lee Yuan‐Hsiang , Hsu Yen‐Chu
Published: June 2015

The gerade states of acetylene at 9‐10 eV have been studied by monitoring the C2 emission. Larger Δv2 excitations are seen than previously reported by Ashfold et al. The observed two‐photon resonant levels show extensive predissociation. Experimental evidence from the two‐color photofragment excitation measurement is given to support the conclusion that the excited‐state ethynyl radical and atomic hydrogen are the corresponding predissociation products. Most C2 emissions seen in this work are due to the subsequent photodissociation of the intermediate C2H to C2 (d3Πg).
Adsorptive Bubble Separation of Dinitrophenol
Authors: Shing Ank‐Kung , Huang Shang‐Da
Published: June 2015

Dinitrophenol was removed from aqueous solution by various adsorptive bubble separation techniques. Foam fractionation of dinitrophenol with hexadecyltrimethylammonium bromide(HTA) was most effective with over 99% removal in 15 min. The addition of a surfactant in greater than stoichiometric amounts was required for effective separation. Solvent sublation of the dinitrophenol‐HTA complex was also effective. The separation efficiency of solvent sublation of dinitrophenol‐HTA was similar to that of foam fractionation. The separation by solvent sublation of dinitrophenol without adding any surfactant was very poor. Adsorbing colloid flotation with Fe(OH)3 was not effective in removing dinitrophenol from aqueous solution.
Studies on 1,2‐Bis(O‐Aminophenoxy)Ethane‐N,N,N′,N′;‐Tetraacetic Acid Chelates of the Tripositive Lanthanide Ions
Authors: Hseu Tong‐Ming , Liu Kei‐Lee
Published: June 2015

The acid dissociation constants of 1,2‐bis(cis‐aminophenoxy)ethane‐N,N,N′,N′;‐tetraacetic acid (H4BAPAT or H4Z), and the stability constants of its chelates with tripositive rare‐earth metal ions have been determined by the potentiometric titration and mercury indicator electrode methods at 15°, 25′ and 35°C and an ionic strength of 0.1 (KNO3). The existence of a monohydrogen chelate species, LnHZ, and the normal chelate, LnZ−, is illustrated. Enthalpy and entropy changes characterizing the formation of the normal chelates and the dissociation of the last two protons of chelating acid have been calculated at 25°C. These functions have been compared with corresponding values for related chelating agents.
Preparation and Catalytic Properties of Transition Metal Doped ZSM‐5 Zeolites
Authors: Wan Ben‐Zu , Yang Tran Chin
Published: June 2015

Metal silicates of ZSM‐5 type structure were prepared by doping silicate gels with chromium, manganese, cobalt, nickel, and copper ions, respectively, followed by reacting hydrothermally. The resultant materials were characterized by the metal content, x‐ray powder diffraction, ion exchange capacity, surface area, thermal stability, and temperature programmed desorption of ammonia for acidity measurement. In addition, the catalytic properties of these metal silicates were examined using ethanol conversion as a probe reaction. The effect of transition metal content on the catalysis for dehydration, dehydrogenation, oligomerization, cracking, and cyclization to the aromatics was established and compared with that of HZSM‐5 catalyst.
Characterization of the SiOT Angle and Cation Effects on 29Si Chemical Shifts Of Zeolites
Authors: Su Ming‐Der , Chao Kuei‐Jung , Chu San‐Yan , Chen Cheu‐Pyeng
Published: June 2015

The quantitative relationships between 29Si chemical shifts and (a) the SiOT (T = Al or Si) angles and (b) the nature of the cations of the alkali forms of zeolites can be account for by the changes of charge density and p electron population of the Si atoms as calculated by the extended Hückel method on cluster models.
Selective Alkaline Protease Catalyzed Hydrolysis of Peptide Esters
Authors: Chen Shui‐Tein , Chang Chung‐Ho , Lin Johnson , Wang Kung‐Tsung
Published: June 2015

Procedures for preparing C‐terminal free peptides from hydrolysis of its corresponding methyl or benzyl esters catalyzed by alkaline protease has been developed. N‐protected peptides having side‐chain ester protecting groups or successive hydrophobic amino acid residues in its sequence are hydrolyzed selectively at C‐terminal only and leave other bonds (β and γ‐ ester or peptide bonds) intact. Compounds which cause a side reaction in base mediated saponification could be hydrolyzed safely by this procedure. Products of this hydrolysis are useful intermediates for fragments coupling in the solid phase peptide synthesis.
Synthesis and Structural Studies on Homo‐and Heterobinuclear Complexes of Cu(II), Ni(II) and Co(II) with Arylideneanthranilic Acid Schiff Bases
Authors: Ibrahim S.A. , El‐Gyar S.A. , El‐Gahami M.A. , Hammam A.M.
Published: June 2015

Homo and heterobinuclear complexes of arylidene‐ anthranilic acids with Cu(II), Ni(II) and Co(II) are prepared and characterised by chemical analysis, spectral and X‐ray diffraction techniques as well as conductivity measurements. Two types of homo‐binuclear complexes are formed. The first has the formula M2L2Cl2(H2O)n where M=Cu(II), Ni(II) and Co(II), L = p‐hydroxybenzylideneanthranilic acid (hba), p‐dimethylaminobenzylideneanthranilic acid (daba) and p‐nitrobenzylideneanthranilic acid(nba) and n = 0–3. The second type has the formula M2LCl3(H2O)n in which M is the same as in the first type, L = benzylideneanthranilic acid (ba), (daba) (in cases of Cu(II) and Ni(II)); and n = 1–5.

Heterobinuclear complexes having the formula (MLCl2H2O) MCl2(H2O)n are isolated by reaction of Cu(II) binary chelates with Ni(II) and/or Co(II) chlorides. These are also characterized and their structures are elucidated.
Tridensenal, A Sesquiterpene of Novel Skeleton from the Taiwanese Liverwort Bazzania Tridens
Authors: Wu Chia‐Li , Chang Shu‐Jen , Tori Motoo , Furuta Hirosuke , Sumida Aya , Asakawa Yoshinori
Published: June 2015

The sesquiterpene aldehyde, tridensenal, of previously unknown skeleton was isolated from the Taiwanese liverwort Bazzania tridens. The structure of tridensenal was elucidated on the basis of spectral data and proved by synthesis of the diastereomeric mixture.
Reactions of Nadic Anhydride at High Temperatures
Authors: Chen Leo‐Wang , Chern Yaw‐Terng
Published: June 2015

The reaction of nadic anhydride(NA) at high temperature under oxygen or oxygen‐free conditions was investigated in this report in order to understand the cross‐linking behavior of nadic end‐capped polyimides. In this study, 13C‐NMR, mass spectra as well as IR spectroscopy were employed for understanding the reactions involved. In ampule tests, NA was heated after sealing in air or under nitrogen, The dimer, trimer and tetramer of NA were found when heated at 260°C for 30 min. and their possible chemical linkage is shown. More complicated products could be obtained when heating For longer time. The cleavage of double bond was observed when NA was heated at about 340°C and the linkage containing oxygen was found when scaled in air. The molecular weight of product increased in this case.
Solvent Extraction and Spectrophotometric Determination of Uranium Using α‐Benzoin Oxime as Chelating Agent
Authors: Chang Liang Chien , Chen Shou Nan , Gi Hung Jang
Published: June 2015

Solvent extraction of uranium by a chloroform solution of α‐benzoin oxime was studied and the formation of uranium‐α‐benzoin oxime complex described. The uranium‐α‐benzoin oxime complex has two maximum absorbance at 350 nm and 427 nm. A constant absorbance was obtained for 1 × 10−3 M uranium when the concentration of α‐benzoin oxime was higher than 1.2 × 10−2 M. Ions of Ag+, Fe3+, V5+, Cu2+, and W6+ were found to have interference.

A solution containing 0.1–10 mg uranium at pH 1.6–6.8 was extracted with 1 × 10−3 M −2 × 10−3 M α‐benzoin oxime solution in chloroform. With single extraction, the maximum amount of uranium passing into organic layer was at least 98%. Under this condition the presence of diverse ions except V5+ does not significantly interfere the extraction of uranium.
Preparation of 3,4,5,3′‐Tetramethoxy‐4′,5′‐Methylenedioxybenzophenone and Bis‐(3‐Methoxy‐4,5‐Methylenedioxy)‐Benzophenone
Authors: Zee Sheng‐Hsu , Chou Shan‐Yen
Published: June 2015

The preparation of 3,4,5,3′‐tetramethoxy‐4′,5′‐methylenedioxybenzophenone (I) and bis‐(3‐methoxy‐4,5‐methylenedioxy)‐benzophenone(II) were reported. The synthesis of these compounds were accomplished using two separate synthetic routes starting from gallic add and its derivatives to the corresponding benzils. Both compound I and II were obtained by benzilic acid rearrangement of the benzils and followed by an oxidative decarboxylation.
Optically Active Sulfoxides and Low‐Valent Titanium in Asymmetric Synthesis of Natural Products
Authors: Guysolladié
Published: June 2015

The total synthesis of lasiodiplodin via optically active sulfoxides and the preparation of polyenes through low valent titanium reagents are described.
Binuclear Complexes. II. Electron Paramagnetic Resonance Study of Binuclear Copper Complexes with α‐Diimine Ligand
Authors: Wen‐Jwuwang  , Chen Cheu‐Pyeng
Published: June 2015

A series of biouclear copper (II) complexes containing a‐diimine ligand has been synthesized and characterized by electron paramagnetic resonance spectroscopy. The copper complexes of the form [Cu(dien)D](ClO4)2 or [Cu2(dien)2L](CIO4)4, where dien is diethylenetriamine, L' is monodentate ligand and L is bridging ligand, were studied. The EPR spectra were recorded in solution and frozen glassy solution. In the frozen solution spectra, the values of G‖ are in the range of 2.10 to 2.20, and the g⊥ are in the range of 2.03 to 2.06. Furthesmore, the values of A‖ are in the range of 170 to 188 gauss, and the A ⊥ are in the range of 17 to 32 gauss. The data indicate that the structure of Cu(II) complexes is axial symmetry in square pyramidal form.
Two New Resolution Processes for the Preparation of (+)‐S‐2‐(6‐Methoxy‐2‐Naphthyl)Propionic Acid (d‐Naproxen)
Authors: Chang Kuo‐Mien , Wu Shihn‐Sheng , Yhn Shiow‐Ling , Wang Yi‐Fong
Published: June 2015

Two new chemical resolution processes have been developed for the preparation of ( + )‐S‐2‐(6‐methoxy‐2‐naphthyl)‐propionic acid (d‐Naproxen). One is via the diastereoselective aminolysis of amide 4 with piperidine and the other is via the selective stoichiometric crystallization of amide 5
Synthesis of Some New Pyrazolo[3,4‐b]Pyridlne and Pyrazolo[3,4‐d]Pyrimidine Derivatives1
Authors: Younes Mansour I. , Abbas Hessan H. , Metwally Saoud A.M.
Published: June 2015

Several pyrazolo[3,4‐b]pyridine (3,4) and pyrazolo‐[3,4‐d]pyrimidine (5‐13) derivatives were prepared using 5‐amino‐l‐(5‐ethyl‐5H‐1,2,4‐triazino[5,6‐b]‐indol‐3‐yl)‐lH‐pyrazole‐4‐carbonitrile (2). The pyridine derivatives 3 and 4 were obtained by reaction of 2 with malononitrile and ethyl cyanoacetate, respectively, while pyrimidine analogs 5‐13 were synthesized cither by a one‐step or multi‐step sequence.
Electrochemical and Spectral Studies of Sterically Hindered Water‐Soluble Iron Tetrakis(Sulfonatomesityl)Porphine
Authors: Cheng Shu‐Hua , Chen Yu‐Shen , Su Y. Oliver
Published: June 2015

Sterically hindered water‐soluble iron(III) tetrakis(sulfonatomesityl)porphine (FeTSMP) exists exclusively in its monomer form in neutral and basic aqueous solutions. The acid dissociation constant (pKa) for FeIIITSMP is 6.6. The FeIII/IITSMP couple has a formal reduction potential at −0.22 V (vs. Ag/AgCl) in an acidic buffer solution. The E°‐pH diagram shows that E° is independent of pH until the pH is larger than the pKa. The acid dissociation constant for FeIITSMP is 11.7. The redox potential of FeIII/IITSMP shifts positively when imidazole is present, indicating the ligation of imidazole to FeIITSMP. At pH 4.0 and 10.2 buffer solutions, two imidazoles are found to ligate at the iron(III) center with β2 = 104.7 and 104.1, respectively. The E°‐pH diagram indicates that the pKa of (ImH)2FeIIITSMP is 11.3 at 0.03 M imidazole solution. The oxidation of FeIIITSMP could involve two one‐electron transfer processes, namely, one electron oxidation at the iron center, while another at the porphyrin ring. The two one‐electron oxidations are found to overlap at pH = 5.5 and separate as the pH increases by shifting of the potential at the iron center, which is pH dependent. The radical cation of porphyrin ring is not stable and decomposes rapidly in water.
Novel W(CO)6‐Promoted C‐S Bond Cleavage Reactions of Dithianes. X‐Ray Structure of 9,9′:9,9′‐Terfluorene
Authors: Kuo Chi‐Hong , Lnh Tien‐Yau , Cheng Ming‐Chu , Peng Shie‐Ming
Published: June 2015

The reactions of dithianes with W(CO)6 in refluxing chlorobenzene give dimeric alkenes and their reduced products; fluorenone derivative yielding trimer 8. A radical mechanism is suggested. The structure of 8 has been determined by a single‐crystal X‐ray diffraction study. Crystal data: P21/n; a = 11.948(5), b = 16.8795(14), c = 13.491(6) Å, β = 105.03(3)°, Z = 4, V = 2628(2) Å3; RF = 0.061, RWF = 0.051 for 2142 reflections and 353 variables.
Facile Synthesis of Biologically Active Peptides Using Phase Transfer Reagents as C‐Terminal Protecting Group
Authors: Chen Shui‐Tein , Wang Kung‐Tsung
Published: June 2015

Phase‐transfer reagents (basic, neutral, and acidic) can temporarily protect carboxyl groups by salt formation of C‐terminal free amino acids or peptides during peptide synthesis. The salts of amino acids or peptides behave as RNH2 rather than RNH3+. At least there is a sufficient concentration of the free amine to act as a nucleophile under the reaction conditions. Many biologically active small peptides have been synthesized by this procedure. No racemization was detected. Unusual amino acids such as β‐alanine, and ε‐aminohexanoic acid can be incorporated into peptides in high yields.
Hydrogenation of Carbon Dioxide on Iron Manganese Catalysts
Authors: Kuci Chi‐Kung , Chen Wen‐Shing , Lee Min‐Dar
Published: June 2015

The synthesis of hydrocarbons from hydrogenation of carbon dioxide has been studied on a series of coprecipitated iron‐manganese catalysts. Kinetic measurements, X‐ray diffraction, Mössbauer spectroscopy, and temperature‐programmed reaction of adsorbed species were used for activity tests and catalyst characterizations. The results showed that the yields of low‐carbon olefins decrease, whereas the amount of methane increases with increasing manganese content in catalysts. The conversion to hydrocarbons is suppressed by the reverse water‐gas shift (RWGS) reaction equilibrium. Mössbauer spectra and XRD patterns of catalysts after reaction indicate that catalysts are severely oxidized; it is speculated that the olefin producing surface structure in CO hydrogenation may be destroyed by this oxidation. A pulse‐reactor study of the Boudouard reaction showed that manganese has the effect of suppressing CO dissociation and thus decreasing carbon content on catalysts. For CO2 hydrogenation, the affinity to carbon on catalysts is important; therefore manganese is not a good promoter. Among all catalysts tested, pure iron has the best selectivity to olefinic and long‐chain hydrocarbons.
Mössbauer Spectroscopic Studies of Ferrocenylaldimines and their TCNQ Complexes
Authors: Lee Chin‐Jhan , Wei Ho‐Hsiang
Published: June 2015

A series of ferrocenylaldimines (Fc‐CH=N‐R) has been prepared by Schiff base condensation of formylferrocene with polyacenylamines RNH2 where R = naphthyl, 5,6,7,8‐tetrahydronaphthyl, anthracenyl, and pyrenyl groups. This step was followed by oxidation with TCNQ to give [Fc‐CH = N‐R][TCNQ]2 salts. The electronic state of iron in these compounds was investigated by means of57Fe Mössbauer spectroscopy.
Improved Method of Extraction and High‐Performance Liquid Chromatographic Separation of Ganoderic Acids from Ganoderma Lucidum
Authors: Sye Wen‐Fa
Published: June 2015

A rapid and efficient method is described for the extraction of ganoderic acids from Ganodemia lucidum by means of a small Sep‐Pak C18 cartridge. The application of high‐performance liquid chromatography to determine the chemical compositions of strains of Ganoderma lucidum is also reported.
Synthesis of 1‐phenyi‐1H‐tetrazolo[4,5‐d]tetrazole and 5‐aryl‐1‐(4‐bromophenyl)‐1,2,4‐triazolo[4,3‐d]tetrazoles
Authors: Moustafa M. A. A. , Ismaiel A. M. , Eisa H. M. , El‐Emam A. A.
Published: June 2015

l‐Phenyl‐lH‐tetrazol‐5‐yIhydrazine (2) was reacted with nitrous acid to yield 1‐phenyl‐lH‐tetrazolo[4,5‐d]tetrazole (3). l‐Arylidene‐2‐(l‐phenyl‐lH‐tetrazol‐5‐yl)hydrazines (4) were generally reactive towards electrophilic reagents. When treated with bromine in acetic acid, 4 yielded mixtures of 1‐arylidene‐2‐[1‐(4‐bromophenyl)‐lH‐tetrazol‐5‐yl]hydrazines (5a‐d) and 2‐[1‐(4‐bromophenyl)‐lH‐tetrazol‐5‐yl]hydrazidic bromides (6a‐d). Solvolysis of 6a‐d in aqueous acetone yielded 5‐aryl‐1‐(4‐bromophenyl)‐1,2,4‐triazolo[4,3‐d]tetrazoles (7a‐d). The structures of the synthesized compounds were confirmed on the basis of elemental analysis, IR and 1H NMR data.
The Application of Cryptand 22 as a Bifunctional Stationary Phase for Ion Chromatography
Authors: Chen Sih‐Jen , Shih Jeng‐Shong
Published: June 2015

Poly (styrene/divinyl benzene) with cryptand 22 as an anchoring group was synthesized and applied as a bifunctional packing material for the separation of both cations and anions. At pH < 2, the resin can be protonated and applied as an anion exchanger for the separation of anions; with water as eluent, inorganic anions such as F−, Cl−, Br−, NO3−”, I− were well separated. After deprotonation at pH> 10, the resin became a cation exchanger and successfully separated alkali metal ions such as Li+, K+ and Cs+ with methanol as eluent. The effects of solvents, flow rate and temperature on the separation of various ions were also investigated.
Low‐Pressure Chemical Vapor Deposition of Silicon Carbide Thin Films from Organopolysilanes
Authors: Chiu Hsin‐Tien , Wu Pei‐Fang
Published: June 2015

(Me3Si)2SiMe2, (Me3Si)3SiMe and (Me3Si)4Si were used as precursors for the deposition of polycrystalline β‐SiC thin films on silicon substrates at 1000–1200°C in a low‐pressure hot‐wall chemical vapor deposition reactor. The thin films were analyzed by X‐ray diffraction, scanning electron microscopy and X‐ray photoelectron spectroscopy.
Tricarbonyl(dialkylamidocyclohexa‐1,3‐diene)iron: Preparation, Isomerization and Stereochemistry
Authors: Ong Chi Wi , Hwang Wen Shu , Liou Wen Tzong
Published: June 2015

The direct reaction of iron pentacarbonyl with diethylamidocyclohexadiene gave three isomeric tricarbonyliron complexes, 1, 2 and 3. Only 1 isomerized to give 2 under acidic conditions, whereas 3 remained unchanged. The chemical properties of the tricarbonyl(amidocyclohexadiene)iron complexes differed from those of the tricarbonyl(carboxycyclohexadiene)iron complexes. Complex 3 which underwent no hydride abstraction with triphenylmethyl hexafluorophosphate, has an exo stereochemistry.
Synthesis of the Sex Attractant (7Z,11Z)‐Hexadecadienal of the Citrus Leafminer Moth, Phyliocnietis Citrella Stainton
Authors: Yea Yao‐Pin , Chang Chin‐Yuang
Published: June 2015

A component (7Z,11Z)‐hexadecadienal of the sex attractant of the citrus leafminer moth was synthesized through a new (C6 + C3) + C7 approach.
Adsorption Geometry of 4‐Cyanopyridine on Ag Electrode by SERS
Authors: Lan Yueh Hsen , Chang Hua
Published: June 2015

The adsorption of 4‐cyanopyridine (PyCN) on Ag electrode has been studied by surface‐enhanced Raman scattering. The Raman band of the CN group is at 2240 or 2100 cm−1; it appears in various ranges of potential. When a series of potentials was applied stepwise to the electrode, the growing and vanishing of both bands was monitored by an optical multichannel analyzer with a time resolution 1 s or less. Some information about the kinetics of the adsorption and desorption of CN group and about the adsorption geometry of PyCN on the electrode was obtained.
Mass Spectra of Furfuryl Aldoximes and Ketoximes
Authors: Lin Shaw‐Tao , Kuo Yueh‐Hsiung , Lin Yun‐Lian
Published: June 2015

The mass spectra of 8 furfuryl aldoximes and ketoximes were studied under EI and CI conditions. Complicated fragmentation patterns were obtained in EI conditions, including formation of a furfuryl cation radical, furfuryl cation, and [M‐17]+. The relatively simple patterns of cleavage resulted in few major ion peaks contributed from the adducts, protonation products, and dehydration products under CH4‐CI and NH3‐CI conditions. Comparison with the spectra of their isomeric amides indicated no evidence that the isomerization took place from oximes before fragmentation in both ionization methods.
Stereoselective Synthesis of (+)‐Peperomin C
Authors: Zee Sheng‐Hsu , Chou Shan‐Yen
Published: June 2015

The stereoselective synthesis of peperomin C is reported. The key steps include the stereoselective alkylation of the substituted diphenylmethyl group to the r‐butyrolactone ring and transformation of the carbonyl group to the other side in the butyrolactone ring by reduction of the lactone carbonyl followed by degradative oxidation.
The Constituents of Cynanchum Taiwanianum
Authors: Chen Zong‐Shiow , Lai Jeng‐Shiow , Kao Yueh‐Hsiung
Published: June 2015

The isolation and identification of eleven crystalline components from the aerial part of Cynanchum taiwanianum Yamazaki (Asclepiadaceae) are described. Their structures were determined on the basis of spectral evidence and chemical transformation. Besides caffeic acid, β‐amyrin, and methyl phaeophorbide a, the isolated flavonoid components are classified into two groups, i.e. kaempferol derivatives (kaempferol, astragalin, afzelin, trifolin) and quercetin derivatives (quercetin, isoquercitrin, quercitrin, hyperin).
Isolation of a Bioactive Sterol from the Soft Coral Lobophytum Mirabile
Authors: Sheu Jyh‐Horng , Veh Tsuey‐Hua
Published: June 2015

A cytotoxic sterol, 24ξ‐melhylcholestane‐3β,5α,6β,25‐tetrol 25‐monoacetate (1) was isolated from the soft coral Lobophytum mirabile. This polar sterol showed moderate cytotoxicity toward P388 cells.
Asymmetric Diels‐Alder Reactions of Chiral Menthyl α‐Sulfinylacrylates
Authors: Yang Teng‐Kuei , Lee Dong‐Sheng , Teng Tsung‐Fan , Jong Ting‐Ting , Chien Mei‐Yueh
Published: June 2015

Introducing two chiral auxiliaries, sulfoxide and menthol, into an acrylate would have either matched or mismatched pair systems. The presence of chiral menthol in α‐sulfinylacrylates can change the diastereoselectivity from 24% d.e. to a single diastereomer by manipulation of the double asymmetric strategy.
Enantioselective Synthesis of N‐[(S)‐Ethoxycarbonyl‐3‐phenylpropyl]‐L‐alanyl‐L‐proline from Chiral Synthon Prepared Enzymatically; A Practical Method for Large‐Scale Synthesis
Authors: Tseng Tsung‐Chin , Duo Tsai‐Hui , Wang Yi‐Fong
Published: June 2015

Efficient procedures have been developed for the stereospecific synthesis of Angiotensin‐converting enzyme inhibitor, Enalapril. The starting material, (R)‐2‐hydroxy‐4‐phenylbutyronitrile, is prepared from lipase‐catalyzed acetylation. This process is useful for multigram‐scale synthesis.
Intramolecular Diels‐Alder Reactions of Furans with Allenyl Ethers. Formation of Indanone and Tetralone
Authors: Lin Chu‐Chung , Chen Liang‐Huei , Wu Hsien‐Jen
Published: June 2015

The intramolecular Diels‐Alder reactions of the furans 3, 11a and 11b produced indanone 6 and tetralones 14a and 14b respectively, presumably via the corresponding allenyl ethers 4, 12a and 12b and the intramolecular cycloadducts 5, 13a and 13b.
Probing the Double Bond and Phase Properties of Natural Lipid Dispersions by Cross Polarization/Magic Angle Spinning 13C NMR
Authors: Chi Lang‐Ming , Hsieh Chemg‐Huain , Wu Wen‐Guey
Published: June 2015

Solid‐state high resolution 13C NMR spectra of bovine brain sulfatide, egg sphingomyelin, egg phosphatidylcholine, and cholesterol/phosphatidylcholine dispersions were obtained by the cross‐polarization/magic angle spinning (CP/MAS) method as functions of contact time, temperature and composition. Quantitative analysis of the chemical shift and linewidth data indicate that in the liquid‐crystalline state the hydrocarbon chains of sulfatide are packed less orderly than those of sphingomyelin, and that there are two or more conformers for the ceramide residues of natural sphingolipids. The fatty acid double bond showed higher mobility than that of sphingosine as monitored by the signal intensity profiles as a function of contact time. The same approach was used to study the coexisting Lα (liquid‐crystalline phase) and β (cholesterol‐rich characterized phase) two‐phase region of cholesterol/phosphatidylcholine mixtures. Without isotope enrichment, structural and phase properties of natural lipid dispersions can be obtained easily by monitoring the chemical shift, the signal intensity and the linewidth of l3C NMR spectra.
Electron Delocalization in a New Mixed‐Valence σ‐Bridged Biferrocenium Cation
Authors: Dong Teng‐Yuan , Lee Ting‐Yu
Published: June 2015

The physical properties of mixed‐valence 1,3‐diferrocenyl‐propan‐1‐one (1) are reported. The Mössbauer spectrum of mixed‐valence cation 1 at 300 K shows two doublets, one for a Fe11 metallocene (ΔEQ = 2.192 mm s−1) and the other for a FeIII metallocene (ΔEO = 0.179 mm s−1) Thus, the thermal electron‐transfer rate in 1 is less than the time scale of the Mössbauer technique (∼107 s−1). Furthermore, the NMR, electrochemical IR, and near‐IR data conclusively indicate that there is no significant interaction between the two ferrocenyl moieties.
Application of a Cation‐Exchange Membrane to Determine Cations of Trace Metals in River Water
Authors: Hung Jia‐Jang , Wong Chih‐Chich
Published: June 2015

Donnan‐membrane‐equilibrium graphite‐furnace atomic‐absorption spectrophotometry (DME‐GFAAS) has been developed to determine cations of trace metals in river water. The method employs a cation‐exchange membrane to separate metal cations from their complexes; both total and cationic forms of metals were determined by means of GFAAS. The sensitivity of the method for the measurement of trace metal cations is determined by the detection limits of GFAAS for the metals of interest. Comparable concentrations of metal cations in water from NBS and from the Erhjen river were obtained between the DME‐GFAAS and calculated (WATEQ4F) methods, indicating that the developed method is promising for natural fresh waters. The effect of pH on the distribution of metal cation in the NBS river water is significant for Cu and Pb; concentrations of these cations increase with decreasing pH. However, the concentrations of Cd and Zn cations do not vary with pH except that the concentration of the Zn cation decreases significantly as the pH value increases beyond 9. The method was applied to measure the capacity of complexing Cu in Chung‐Lu river water, which was estimated to be 2.3 μM.
Reaction of Trimethylbenzene over Alumina‐Pillared Montmorillonite
Authors: Ko An‐Nan , Chemg Hsin‐Chuan
Published: June 2015

The reaction of trimethylbenzene (TMB) over alumina‐pillared montmorillonite (Al‐PM) had been investigated in a fixed‐bed flow reactor at 300 °C and atmospheric pressure. Al‐PM calcined in the range 300‐500 °C exhibited decreased layer distance, surface area and acid amount. The strong acid sites of Al‐PM calcined at 500 °C were greatly diminished according to measurements of ammonia temperature‐programmed desorption. Under our conditions the reaction proceeded mainly via isomerization and disproportionation with little dealkylation. The conversion of reactant decreased in the order 1,2,3‐TMB ≥ 1,2,4‐TMB > 1,3,5‐TMB and the selectivity of isomerization in the order 1,2,3‐TMB > 1,3,5‐TMB > 1,2,4‐TMB, corresponding to the order of diminishing thermal instability. Both the catalytic activity and the selectivity ratio of disproportionation to isomerization decreased with increased calcined temperature and time‐on‐stream. o‐Xylene content in the total xylene produced from 1,2,4‐TMB or 1,2,3‐TMB greatly exceeded the composition at thermodynamic equilibrium. These results arc consistent with the decrease of both the strong acid sites and the pore size of Al‐PM which exhibits the restricted transition state selectivity.
Industrial Protease “Alcalase” as a Catalyst in Organic Synthesis: Resolution of Natural and Unnatural Amino Acids
Authors: Chen Shui‐Tein , Hsiao Shu‐Chyong , Chiou Aih‐Jing , Wu Shih‐Hsiung , Wang Kung‐Tsung
Published: June 2015

Procedures have been developed for the resolution of natural and unnatural amino acids using soluble or immobilized industrial enzyme “Alcalase” as catalyst. The specificity of enzyme on different amino acids and the stability of both free and immobilized enzyme have been studied.
A Facile One‐Pot Synthesis of 4‐Acyl and 4‐(1‐Hydroxyethyl)Sydnones
Authors: Tien Hsien‐Ju , Fang Gwo‐Ming , Lin Shaw‐Tao , Tien Ling‐Ling
Published: June 2015

A series of 4‐formyl‐, 4‐acetyl‐ and 4‐(l'‐hydroxyethyl)sydnones have been prepared in good yields by reaction of sydnone with butyllithium or a Grignard reagent and N,N‐dimethylformamide, N,N‐dimethylacetamide and acetylaldehyde, respectively.
The Exact Icosahedral Symmetry Relations for Atomic Overlaps, Molecular Orbitals and Vibrational Species of C60 Buckyballs
Authors: Wang Bo‐Cheng , Chiu Ying‐Nan
Published: June 2015

A computer adapted vector method and Euler angle transformation procedures are used to generate the relationship between the atomic orbitals of icosahedral C60 Buckminsterfullerene cluster and to produce symmetry adapted molecular orbitals and vibrational species. The atomic overlaps based on the orientational relationship of the orbitals are used to compute the approximate molecular orbital energies and normalization constants. One of the vibrations of Au, symmetry is used to interpret the isomeric (dyotropic) rearrangement that breaks and forms two bonds to change two pentagons to two hexagons and vice versa.
Natural Bond Orbital Study on the Nature of Binding in the H2 Molecule
Authors: Chang Tse‐Chiang , Hwang Tsung‐Sung
Published: June 2015

We use the natural bond orbital (NBO) method to decompose a MO wavefunction into the intuitive valence bond (VB) structures. At least two natural orbital type MO are required to describe the essential binding of the H2 molecule at all inter nuclear distances. At first the MO wavefunction is transformed into an unrestricted Hartree‐Fock wave‐function consisted of non‐orthogonal localized orbitals u' and v', and then the NBO method is used to decompose u' and v' into the physical meaningful orthogonal localized orbitals. Our results show that the orbitals u' and v' are decomposed into an atomic and an overlap parts. The latter part gives rise to the conventional ionic structure in the VB picture.
Substitution Reactions of Sulchemfonylated Sulfolenes with the Carbanion of Dimethyl Malonate
Authors: Chou Ta‐Shue , Yang Teng‐Kuci , Ko Chung‐Wen
Published: June 2015

The reactions of 4‐alkyl‐4‐(phenylsulfonyl)‐2‐sulfolenes with excess carbanion of dimethyl malonate in refluxing THF have been studied. The substitution reaction takes place at the 3‐position via an addition‐elimination process so that 3,4‐disubstituted 2‐sulfolenes are obtained. These products are isomerized to the corresponding3‐sulfolenes under basic conditions.
Vitamin E: Or Why We Don't Go Rancid
Authors: Ingold Keith U. , Burton Graham W.
Published: June 2015

The authors' chemical studies on vitamin E are summarized. These studies provide very strong support for the view that vitamin E owes its biological activity solely to the fact that it acts as a general purpose, lipid‐soluble, peroxyl‐radical‐trapping antioxidant.
Clerodane‐Type Diterpenoids from the Taiwanese Liverwort Schistochila Acuminata
Authors: Chen Jing‐An , Huang Chyuan‐De , Wu Chia‐Li
Published: June 2015

Three cis‐clerodane‐type acids 3‐5 and one methyl ester 9 were identified from the liverwort Schistochila acuminata. The two new acids 3 and 5 were 12E and 12Z geometric isomers and the methyl ester 9 was first reported from nature.
Syntheses and Reactions of Rhenium Carbamoyl Complexes of the Type (CO)4Re(NH2R)(CONHR) (R = Ethyl, Allyl or Isopropyl)
Authors: Liao Wen‐Jui , Wang Yen‐Ju , Chen Jhy‐Der , Lin Ying‐Chih , Liu Ling‐Kang
Published: June 2015

Carbamoyl complexes, (CO)4Re(NH2R)(CONHR)(R = ethyl, 1; R = allyl, 2; R = isopropyl, 3) were prepared by reactions of (CO)5ReBr (or (CO)5ReCH2SiMe3) with appropriate amines. Complexes 1, 2 and 3 reacted with CH3CH2COCl to give Re(CO)5(NH2R)+Cl− (R = ethyl, 4; R = allyl, 5; R ‐ isopropyl, 6). Complex 5 undergoes nucleophilic attack by KOMe to give the alkoxycarbonyl complexes (CO)4Re(NH2‐Allyl)(COOMe), 7. Complexes 4, 5, 6 and 7 were transformed to the corresponding carbamoyl complexes by reacting with appropriate amines. The reactions between the carbamoyl complexes and R″OH/CHCl3 in air at room temperature gave the proposed products [(CO)4Re(NH2R)]2O (R = allyl, 8; R = isopropyl, 9), respectively. Complex 8 can also be prepared by heating 7 in CDCl3 at 63–68°C for several days.

The structure of 1 was confirmed by a X‐ray crystallographic study. Crystallographic data: space group P21/c, a = 8.193 (3) Å, b = 19.273 (3) Å, c = 9.348 (8) Å, β = 110.37 (4)°, V = 1383.68 Å3, Z = 4; R(F) = 0.027, Rw(F) = 0.030, based on 1888 reflections with I > 2.5σ(I). The other complexes were characterized by 1H NMR, 13CNMR, IR and mass spectra.
Dialkylative Cyclization Reactions of 3‐(Phenylthio)‐3‐Sulfolenes
Authors: Chou Shang‐Shiag P. , Sung Chin‐Chung , Sun Der‐Jen
Published: June 2015

3‐(Phenylthio)‐3‐sulfolene (4) underwent bridged dialkylative cyclization with 2‐methylene‐1,3‐diiodopropane to give the bridged bicyclic 3‐sulfolene 23, and spirodialkylation with 1,4‐diiodobutane and 1,5‐diiodopentane to give the spiro bicyclic 3‐sulfolenes 15 as the major product. The reaction of 4 with 1,3‐diiodopropane led to the fused bicyclic 2‐sulfolene 12. 3‐(Phenylthio)‐3‐sulfolenes bearing an ω‐iodoalkyl group at the C‐2 position gave the fused bicyclic 2‐sulfolenes 28 and/or the spiro bicyclic 3‐sulfolene 29 depending on the chain length.
Crystal Structure of frans‐Dichloro(c‐Meso‐3,5,7,7,10,12,14,14‐Octamethyl‐1,4,8,11 ‐Tetraaza Cyclotetradeca‐4,11‐Diene)Cobalt(lll) Perchlorate
Authors: Lu Tian‐Huey , Chen Bor‐Hann , Chung Chung‐Sun
Published: June 2015

The crystal structure of the title compound has been solved by X‐ray diffraction. [CO(Cl)2(N4C18H36)]‐(ClO4), Mr = 537.79, triclinic, P1, a = 6.974(4), b = 8.530(1), c = 11.061(2) Å, α = 98.47(1), β = 106.56(3), γ = 93.02(3)°, V = 620.8(4) Å3, Z = 1, Dx = 1.439 Mg m−3, λ(MoKα) = 0.7093 Å, μ = 0.96 mm−1, F(000) = 291.93, T = 297(3) K, R = 0.072, Rw = 0.085 for 2121 observed reflections. The Co(III) is six‐coordinate with the four N atoms of the macrocyclic ligand equatorial and two Cl ions axial, thereby resulting in a tetragonally distorted octahedral geometry. Aside from the perchlorate group, there exists a non‐crystallographic inversion center at the Co(III) ion for the macrocyclic ligand and the two Cl ions which are bonded to the Co(III) ion.
Studies on the Formosan Soft Corals I‐Cytotoxic Cembrane Diterpenes from Sarcophyton Trocheliophorum
Authors: Wu Yang‐Chang , Hsieh Pei‐Wen , Duh Chang‐Yih , Wang Shang‐Kwei , Soong Keryea , Fang Lee‐Shing
Published: June 2015

Two cytotoxic cembranoid diterpenes, (+)‐isosarcophytoxide (1) and ( + )‐isosarcophine (2), were isolated from the soft coral Sarcophyton trocheliophorum by cytotoxicity‐guided fractionation. These two compounds demonstrated potent cytotoxicity against P‐388 and HL‐60 cells.
Theoretical Calculations of Dipole Moments, Polarizabilities, and Hyperpolarizabilities of HF, OCS, O3, CH3F, and CH3Cl by Local Density Approximation
Authors: Chong Delano P.
Published: June 2015

The dipole moments, polarizabilities, and hyperpolarizabilities of five molecules (HF, OCS, O3, CH3F, and CH3Cl) have been computed at their experimental equilibrium geometries using the deMon density functional program. For molecules of such sizes, we augmented the basis set of valence double‐zeta plus polarization functions with field‐induced polarization functions. Contamination of least‐squares fitted parameters by higher‐order hyperpolarizabilities have been greatly reduced by fitting the field‐dependent dipole moments to eighth order polynomials using as many as 37 points per molecule. The results compare well with experiment.
Magnetic and Spectral Properties of Heterotrinuclear Acetates [Ru2Co(μ3‐O)(μ‐CH3CO2)6(Py)3]n+ (n = 0 or 1)
Authors: Dong Teng‐Yuan , Lee Hui‐Shien , Lee Ting‐Yu , Hsieh Chia‐Feng
Published: June 2015

The preparation and physical properties of the new heterotrinuclear acetates, [Ru2CO(μ3‐O)(μ‐CH3CO2)6(Py)3] (Ru2Co(II)) and [Ru2Co(μ3‐O)(μ‐CH3CO2)6(Py)3)l3 (Ru2Co(III), Py = pyridine), are reported. Three reversible one‐electron‐redox waves are observed at 1.19, 0.40, and −1.24 V vs Ag/Ag+ electrode for Ru2Co(lI) in CH2Cl2. The complexes of Ru2Co(II) and Ru2Co(III) show an intense visible absorption at 570 (ϵ 5950 M−1 cm−1) and 551 nm (ϵ 7240 M−1 cm−1), respectively. The magnetic susceptibilities of both complexes were also measured from 4.2 to 300 K. The resulting least‐squares fit parameters for Ru2Co(II) areJRuCo = −9 cm−1, JRuRu = −22 cm−1, gCo, = gRu= 2.19.
Spectroscopic Studies of 1‐Aryl‐2,2‐Dichlorocyclopropanes
Authors: Lin Shaw‐Tao , Yao Yi‐Fen
Published: June 2015

Seventeen 1‐aryl‐2,2‐dichlorocyclopropanes were examined by using IR, 13C NMR, and mass spectrometry. The data obtained from IR and 13C NMR spectra indicate that the bond strength of carbon‐chlorine on the cyclopropane ring and the electron density of that carbon depend on the substituent. The mass fragmentation patterns of compounds in this series resemble those of the dibromo analogues. The fragmentation mechanism is proposed to involve the formation of indenium ion through an electrocyclization.
Rate of Reaction of Electron Transfer over a Long Range and Mediated by a Solvent
Authors: Chen Jin‐Ming , Mou Chung‐Yuan , Lin S. H.
Published: June 2015

We present a simple quantum mechanical model for solvent bridge‐mediated long‐range nonadiabatic electron‐transfer reaction rate. A perturbation theory using a one‐electron model is employed to treat the electronic transition element that includes donor, acceptor and bridge unit wave functions. Reaction‐coordinate activation is treated by high‐temperature approximation. The pre‐exponential factor in the rate coefficient becomes dependent on the distance between donor and acceptor; the decay length depends strongly on the driving force and is effective at a large range if the level of energy of the donor is nearly that of the bridge. This condition is satisfied for a process of electron transfer with excited donor molecules or in the highly exothermic regime.

According to a simple model calculation, the non‐existence of an “inverted” regime in highly exothermic reaction is favored for solvent media with large relative permittivity and low‐lying HOMO (highest occupied molecular orbital) or LUMO (lowest unoccupied molecular orbital). In the normal regime in which the driving force (ΔG°) is positive or nearly zero this effect at large‐range is negligible, and transfer of the electron occurs mostly at the distance of contact.
Mössbauer and Magnetic Studies on the Spin‐State Transitions of Iron Complexes
Authors: Wei Ho‐Hsiang
Published: June 2015

Mössbauer and magnetic studies on the spin‐state transitions in various complexes of iron(II) and iron(III) ions have received considerable attention. The present account deals with some examples of the effects of intraligand substitution and sample size on the spin‐state transitions of 5T2 ↔ 1A1 for iron(II) and 6A1 ↔ 2T2 for Iron(III)‐complexes. A new instance of 3T1 ↔ 5T2 spin‐crossover Fe(II)‐complex is reported.
Syntheses and Reactions of Sulfur‐ and Phosphorus‐ Ylide Metal Complexes Promoted with Phase‐Transfer Catalysts and Hydrolysis of Bis(diphenylphosphino)methane
Authors: Lin Ivan J. B. , Shen H. I.
Published: June 2015

Phase‐transfer catalysts (PTC) promoted synthesis of sulfur‐ and phosphorus‐ylide complexes of Pd(II), Pt(II) and Au(I). Because in most cases, the presence of PTC enhances the rate of formation of ylide complexes, this method is advantageous over the conventional one under anhydrous conditions. Reactions of these ylide complexes are described. Basic hydrolysis of dppm (dppm = Ph2PCH2PPh2) in Pt‐dppm complexes was also promoted by PTC and produces PPh2Me and PPh2O− (or PPh2OH) ligands. Other products from various Pt‐dppm reactions are discussed.
Chemistry of α‐Ketoacyl Metal Complexes
Authors: Chen Jwu‐Ting
Published: June 2015

The α‐ketoacyl complexes constitute a new family of organometallic compounds. The α‐ketoacyl ligands have a strong influence and generally follow a decreasing order of acyl > α‐ketoacyl > alkyl or aryl. The oxalyl conformation exhibits planar s‐cis, perpendicular and planar s‐trans structures. In comparison with the standard C(sp2)‐C(sp2) bond, the oxalyl C‐C bonds of the α‐ketoacyl ligands are relatively long, indicating that the electronic derealization between the oxalyl carbonyls are of the least importance. The weak C‐C bond between the α‐ketoacyl carbonyls affords a driving force of the decarbonylative reactivity of such ligands; it is also responsible for the difficulty of formation of the α‐ketoacyl complex via insertion of CO into the metal‐acyl bond. However, α‐ketoacyl complexes can be kinetically stable. Kinetic studies of decarbonylation of the α‐ketoacyl complexes provided a profound understanding of the mechanism of novel catalytic reactions of double carbonylation. The α‐ketoacyl complexes show promise to explore rare acyl migration and the reductive coupling of C(sp2)‐C(sp2) bonds in a fundamental way.
Correlation Analyses of Solvolytic Rate Data with Single‐ and Dual‐Parameter Hammett Equations
Authors: Liu Kwang‐Ting
Published: June 2015

The results of detailed examinations on the comparison of Hammett‐type correlation analysis of solvolytic rate constants with single‐ and dual‐parameter equations are summarized. From the difference of ρ values, the variation of γ values with numbers of data points, the solvent intervention in the standard reactions for defining σ+ constants, the influence of o‐methyl group on the reactivity of the reference substrate (tert‐cumyl derivatives), and the behavior of the α‐aryl group in highly congested systems, it could be concluded that both the Hammett‐Brown and the Yukawa‐Tsuno treatments of solvolytic rate constants are only approximations. Although in some cases the use of the dual‐parameter Yukawa‐Tsuno equation (Eq. 4) could give a better correlation and a more proper explanation than the use of the single‐parameter Hammett‐Brown equation (Eq. 2), in other cases the excellent correlation observed from the former might be merely a computational artefact. Therefore, the result obtained from the Yukawa‐Tsuno equation should be interpreted with caution.
Substitution Reactions of 3‐Sulfolenyl Carbanions
Authors: Chou Ta‐Shue , Chou Shang‐Shing P.
Published: June 2015

3‐Sulfolenes are easily converted to the corresponding 1,3‐dienes by cheletropic removal of SO2. In addition, the generation of 3‐sulfolenyl anions are achieved under several reaction conditions. Therefore, 3‐sulfolenes serve as butadienyl anion equivalents and this stragegy has been applied to the preparations of substituted dienes and the total synthesis of natural products.
Chemical Constituents of Some Endemic Conifers in Taiwan
Authors: Fang Jim‐Min , Cheng Yu‐Shia
Published: June 2015

Chemical constituents of conifers of families of Cupressaceae, Pinaceae and Taxodiaceae, of which endemic species such as Chamaecyparis taiwanensis, Chamaecyparis formosensis, Calocedrus formosana, Pinus armandii, Tsuga chinensis and Taiwania cryptomerioides are emphasized. The chemical constituents mainly include terpenes, lignans and flavones. Methods and significance of this research are discussed. Extraction, crystallization and chromatography are general methods for separation of plant constituents. Chemical and spectral methods including IR, MS and NMR are frequently used for structural determination along with X‐ray crystallography and circular dichroic spectroscopy to establish absolute configuration in appropriate cases. Finding hinokitiol from Taiwan cypress has initiated the emerging study of troponoid chemistry and nonbenzenoid aromatic compounds. A norsesquiterpene chamaecynone and a mixture of sesquiterpenes T‐cadinol and T‐muurolol exhibit respectively termiticide and antifidant activities. The flavonoid and stilbene constituents are analyzed to support the chemotaxonomy of armand pine and Taiwan white pine. A study of the constituents of armand pine indicates that 30‐nor‐3β‐methoxyserrat‐14‐en‐21‐one is biogenetically derived from 3β‐methoxyserrat‐14‐en‐21‐one by an oxidative degradation via intermediacy of the 30‐alcohol and the 30‐aldehyde.
Peptide Synthesis in Organic Solvents Catalyzed by an Industrial Alkaline Protease “Alcalase”
Authors: Chen Shui‐Tein , Wang Kung‐Tsung
Published: June 2015

An industrial alkaline protease “Alcalase” is stable (half life > 5 days in ethanol or in t‐butanol) and active in alcoholic solvents (except methanol), and usable as a catalyst for kinetically controlled peptide bond formation in these solvents. We give an overview of our use of alcalase as catalyst in peptide synthesis; it includes 1) the stability of alcalase in various organic solvents; 2) the resolution of N‐protected amino acids at large concentration of organic solvent; 3) the saponification of Fmoc‐peptide esters in high concentration of organic solvent; 4) kinetically controlled peptide bond formation in alcoholic solvent, and 5) enzymatic synthesis of a Cathepsin inhibitor, peptidyl Q‐acyl hydroxamates.