bluuebunny/crossref_metadata_2025_split huggingface dataset:
The First Postsynthetic 5′‐5′ Intercalators in Triplex DNA – Solid‐Phase Postsynthetic Sonogashira Reaction and Homocouplings on Arylacetylenes
Authors: Bomholt Niels , Filichev Vyacheslav V. , Pedersen Erik B. 
Published: April 2009

Abstractmagnified imageWe report herein a new technique for postsynthetic modifications of on‐column oligonucleotides. CPG‐Supported nonamer polypyrimidine oligodeoxynucleotides comprising 2‐(3‐iodobenzyloxy)ethyl phosphate at the terminal 5′‐ends were successfully capped with 1,3‐diethynylbenzene under Sonogashira reaction conditions, resulting in novel intercalating 5′‐5′ linker in alternate strand Hoogsteen triplex‐forming oligonucleotidej (TFO) X. In addition, novel 5′‐5′‐linked alternate strand TFOs, Y and Z, were isolated as a result of on‐column Sonogashira coupling with 1,3‐diethynylbenzene, followed by Cu‐catalyzed oxidative arylacetylenic homocoupling(s) between neighboring terminal arylacetylenes. Linkers X, Y, and Z represent the first postsynthesis 5′‐5′ intercalating linkers for alternate strand TFOs. Reproducibility and verification by independent syntheses using conventional phosphoramidite chemistry and DNA synthesis, as well as thermal stability and molecular modelling studies are included.
Chemopreventive agent sulforaphane enhances radiosensitivity in human tumor cells
Authors: Yu Dong , Sekine‐Suzuki Emiko , Xue Lian , Fujimori Akira , Kubota Nobuo , Okayasu Ryuichi 
Published: April 2009

AbstractSulforaphane (SFN), an isothiocyanate derived from broccoli and other cruciferous vegetables, is a positive regulator of phase II detoxification enzymes and is highly effective in protection against chemically induced cancers by inducing apoptosis and cell cycle arrest. Here, we report that SFN also enhances radiosensitivity in human tumor cells. Cell survival in HeLa human cervix carcinoma cells pretreated with SFN was significantly lower than in cells treated with radiation only. Constant‐field gel electrophoresis and a gamma‐H2AX foci assay showed marked inhibition of DSB repair in irradiated cells treated with SFN, while little inhibition was observed in cells with DMSO (control). In addition, immunofluorescence experiments revealed a significant delay in Rad51 (a key protein for homologous recombination repair) foci formation and disappearance in irradiated cells treated with SFN when compared to the cells with X‐irradiation alone. The dephosphorylation of DNA‐PKcs (a critical nonhomologous end joining protein) was also markedly delayed by SFN pretreatment in irradiated cells. These DSB repair inhibition data partially support the high apoptotic frequency of irradiated cells pretreated with SFN. Furthermore, the combined treatment of X‐rays and SFN (i.p. 300 μmol/kg) in the xenograft model with HeLa cells showed efficient inhibition of in vivo tumor growth. To the best of our knowledge, our study is the first report showing SFN‐enhanced radiosensitivity of tumor cells in vitro and in vivo, which opens the door for a multitude of clinical applications for chemoradiotherapy using SFN. © 2009 UICC
Reorganization of the femoral cortex due to age‐, sex‐, and endoprosthetic‐related effects emphasized by osteonal dimensions and remodeling
Authors: Busse Björn , Hahn Michael , Schinke Thorsten , Püschel Klaus , Duda Georg N. , Amling Michael 
Published: April 2009

AbstractCortical remodeling is of particular importance to femoral strength. However, osteonal morphology and its quantitative changes are still poorly understood. Therefore, osteons as the cortexes basic structural units should serve for histomorphometrical assessment of reorganization mechanisms. Total hip replacement (THR) cases as well as relevant controls were investigated to gain insight into changes within stress shielded as well as age‐ and sex‐associated bone with emphasis on the underlying osseous cell interactions. Control (n = 23) and THR (lifetime Ø14 months, n = 8) femora were prepared to grinding specimen. Osteon density (On.Dn.), osteon area (On.Ar.), haversian canal area (H.Ar.), osteon mean wall thickness (MWT), and cortical porosity (Ct.Po.) were evaluated periosteal and endosteal. Osteonal activity (OA) was determined by mineralization differentiation of active and quiescent osteons. Sex‐ and age‐related differences in osteonal remodeling were evident in controls. Females showed age‐dependent increases of H.Ar. during concomitant changes of On.Ar. and MWT resulting in elevated Ct.Po. at the entire cortex. Males showed this occurrence only periosteal. Increased OA and therefore higher remodeling rates were found in females above 70 years. THR led to decreased On.Dn. at the entire cortex. Periosteal increased OA represented increased periprosthetic remodeling resulting in elevated H.Ar., which enhanced Ct.Po.. Massive losses of endosteal circular osteonal structures following THR are reflected in a spongy reorganized cortex leading to increased Ct.Po.. Imbalances in osteoblast‐osteoclast interactions whose intensity is related to the respective cortex regions occur in both stress shielded and aging bone and may thus contribute to implant failure and fracture risk. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res 2010
Procyanidins‐crosslinked heart valve matrix: Anticalcification effect
Authors: Zhai Wanyin , Chang Jiang , Lü Xiqin , Wang Zheng 
Published: April 2009

AbstractCalcification is one of the key factors for short durability of glutaraldehyde‐crosslinked bioprosthetic heart valves. We have shown previously that procyanidins (PC)‐crosslinked heart valve matrix has low cytotoxicity, perfect mechanical properties, and ideal stability. The aim of this study is to investigate the anticalcification effect of procyanidins and its crosslinked heart valves. Porcine aortic heart valve leaflets were decellularized and crosslinked with PC solution. The inhibition of calcification on PC‐crosslinked heart valves was evaluated by soaking valves in simulated body fluid. The anticalcification effect of PC on valvular related cells was evaluated by culturing cells in the presence of PC. The results showed that minerals deposited on non‐ and glutaraldehyde‐crosslinked valvular matrix in simulated body fluid, and PC could inhibit valve matrix mineralization in a dose‐dependant manner. In addition, PC inhibited osteodifferentiation and calcification of valvular related cells by suppressing alkaline phosphatase activity and mineral deposition of cells. In conclusion, procyanidins can inhibit calcification of valvular matrix effectively by blocking mineral deposition and suppressing alkaline phosphatase activity and calcification of valvular related cells. Therefore, procyanindins‐crosslinked heart valve matrix may be a potential candidate as new bioprosthetic heart valve implants. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 2009
Embezzlement: Don't be a victim!
Authors: Lindquist Stanton C. , Goldberg Stephen R. 
Published: April 2009

AbstractDuring a recession, everyone looks for ways to augment their income—including corporate fraudsters. Don't be a victim! The authors discuss the motivations for embezzlement and then cover control procedures your company can take to prevent it. © 2009 Wiley Periodicals, Inc.
Identifying the O2diffusion and reduction mechanisms on CeO2electrolyte in solid oxide fuel cells: A DFT + U study
Authors: Chen Hsin‐Tsung , Chang Jee‐Gong , Chen Hui‐Lung , Ju Shin‐Pon 
Published: April 2009

AbstractThe interactions and reduction mechanisms of O2molecule on the fully oxidized and reduced CeO2surface were studied using periodic density functional theory calculations implementing on‐site Coulomb interactions (DFT + U) consideration. The adsorbed O2species on the oxidized CeO2surface were characterized by physisorption. Their adsorption energies and vibrational frequencies are within −0.05 to 0.02 eV and 1530–1552 cm−1, respectively. For the reduced CeO2surface, the adsorption of O2on Ce4+, one‐electron defects (Ce3+on the CeO2surface) and two‐electron defects (neutral oxygen vacancy) can alter geometrical parameters and results in the formation of surface physisorbed O2, O2a−(0 <a< 1), superoxide (O2−), and peroxide (O22−) species. Their corresponding adsorption energies are −0.01 to −0.09, −0.20 to −0.37, −1.34 and −1.86 eV, respectively. The predicted vibrational frequencies of the peroxide, superoxide, O2a−(0 <a< 1) and physisorbed species are 897, 1234, 1323–1389, and 1462–1545 cm−1, respectively, which are in good agreement with experimental data. Potential energy profiles for the O2reduction on the oxidized and reduced CeO2(111) surface were constructed using the nudged elastic band method. Our calculations show that the reduced surface is energetically more favorable than the unreduced surface for oxygen reduction. In addition, we have studied the oxygen ion diffusion process on the surface and in bulk ceria. The small barrier for the oxygen ion diffusion through the subsurface and bulk implies that ceria‐based oxides are high ionic conductivity at relatively low temperatures which can be suitable for IT‐SOFC electrolyte materials. © 2009 Wiley Periodicals, Inc. J Comput Chem, 2009
Structures and thermodynamics of biphenyl dihydrodiol stereoisomers and their metabolites in the enzymatic degradation of arene xenobiotics
Authors: Pacios Luis F. , Campos Víctor M. , Merino Irene , Gómez Luis 
Published: April 2009

AbstractA key step in the metabolic degradation of biphenyl xenobiotics is catechol formation upon dehydrogenation of cis‐ and trans‐dihydrodiols in prokaryotic and eukaryotic pathways, respectively. Structure and thermodynamics of stereoisomers of cis‐, trans‐2,3‐biphenyl‐dihydrodiols (I) and their dehydrogenation products (hydroxyketones, II), as well as final catechol (2,3‐biphenyldiol, III) are studied by means of ab initio MP2/6‐311++G(2df,2p)//MP2/6‐311G(d,p) calculations. Formation of stereoisomers I and II is exothermic and endergonic, whereas III is enthalpically and entropically driven. Dehydrogenations are endothermic (ΔH ∼ 1.5–4 kcal mol−1) and exergonic (ΔG ∼ −5 to −7.5 kcal mol−1) without noticeable differences between cis and trans pathways, although the same keto stereoisomer II‐(2S) is found to be the more favored product from both cis‐ and trans‐I. The final II → III tautomerization is thermodynamically enhanced (ΔH ∼ −27, ΔG ∼ −28 kcal mol−1) but the process is shown to have a large activation energy if it had to occur via unimolecular path. Although this tautomerization is generally assumed to be a nonenzymatic process as it involves rearomatization of an oxygenated ring, proton transfer with an anionic intermediate might be a more probable process. © 2009 Wiley Periodicals, Inc. J Comput Chem, 2009
Inhibition of osteoclast formation and function by bicarbonate: Role of soluble adenylyl cyclase
Authors: Geng Weidong , Hill Kathy , Zerwekh Joseph E. , Kohler Thomas , Müller Ralph , Moe Orson W. 
Published: April 2009

AbstractHigh ${\rm [HCO}_3^ - ]$ inhibits and low ${\rm [HCO}_3^ - ]$ stimulates bone resorption, which mediates part of the effect of chronic acidosis or acid feeding on bone. Soluble adenylyl cyclase (sAC) is a bicarbonate sensor that can potentially mediate the effect of bicarbonate on osteoclasts. Osteoclasts were incubated in 0, 12, and 24 mM ${\rm HCO}_3^ -$ at pH 7.4 for 7–8 days and assayed for tartrate‐resistant acid phosphatase (TRAP) and vacuolar‐ATPase expression, and H+ accumulation. Total number and area of TRAP (+) multinucleated osteoclasts was decreased by ${\rm HCO}_3^ -$ in a dose‐dependent manner. V‐ATPase expression and H+ accumulation normalized to cell cross‐sectional area or protein were not significantly changed. The ${\rm HCO}_3^ -$‐induced inhibition of osteoclast growth and differentiation was blocked by either 2‐hydroxyestradiol, an inhibitor of sAC or sAC knockdown by sAC specific siRNA. The model of ${\rm HCO}_3^ -$ inhibiting osteoclast via sAC was further supported by the fact that the ${\rm HCO}_3^ -$ dose‐response on osteoclasts is flat when cells were saturated with 8‐bromo‐cAMP, a permeant cAMP analog downstream from sAC thus simulating sAC activation. To confirm our in vitro findings in intact bone, we developed a 1‐week mouse calvaria culture system where osteoclasts were shown to be viable. Bone volume density (BV/TV) determined by micro‐computed tomography (µCT), was higher in 24 mM ${\rm HCO}_3^ -$ compared to 12 mM ${\rm HCO}_3^ -$ treated calvaria. This ${\rm HCO}_3^ -$ effect on BV/TV was blocked by 2‐hydroxyestradiol. In summary, sAC mediates the inhibition of osteoclast function by ${\rm HCO}_3^ -$, by acting as a ${\rm HCO}_3^ -$ sensor. J. Cell. Physiol. 220: 332–340, 2009. © 2009 Wiley‐Liss, Inc.
Insufficiency fracture of the calcaneum: Sonographic findings
Authors: Arni Delphine , Lambert Véronique , Delmi Marino , Bianchi Stefano 
Published: April 2009

AbstractWe present a case of insufficiency fracture (IF) of the calcaneum diagnosed by sonography (US). An 83‐year‐old woman consulted because of pain and swelling of the left heel without history of trauma. Standard radiographs showed osteoporosis without fracture. US revealed thickening of the calcaneal periosteum associated with edema of the adjacent soft tissues. Color Doppler imaging showed marked increased vascularity of the periosteum. US changes, together with the clinical and radiographic findings, were consistent with an IF of the calcaneum that was confirmed by MRI. The patient was treated successfully by conservative treatment. In the proper clinical setting, US can suggest the diagnosis of IF of the calcaneum. © 2009 Wiley Periodicals, Inc. J Clin Ultrasound, 2009
Periods in missing lengths of rainbow cycles
Authors: Vojtěchovský Petr 
Published: April 2009

AbstractA cycle in an edge‐colored graph is said to be rainbow if no two of its edges have the same color. For a complete, infinite, edge‐colored graph G, define

Then 𝔊(G) is a monoid with respect to the operation n∘m=n+ m−2, and thus there is a least positive integer π(G), the period of 𝔊(G), such that 𝔊(G) contains the arithmetic progression {N+ kπ(G)|k⩾0} for some sufficiently large N. Given that n∈𝔊(G), what can be said about π(G)? Alexeev showed that π(G)=1 when n⩾3 is odd, and conjectured that π(G) always divides 4. We prove Alexeev's conjecture: Let p(n)=1 when n is odd, p(n)=2 when n is divisible by four, and p(n)=4 otherwise. If 2<n∈𝔊(G) then π(G) is a divisor of p(n). Moreover, 𝔊(G) contains the arithmetic progression {N+ kp(n)|k⩾0} for some N=O(n2). The key observations are: If 2<n=2k∈𝔊(G) then 3n−8∈𝔊(G). If 16≠n=4k∈𝔊(G) then 3n−10∈𝔊(G). The main result cannot be improved since for every k>0 there are G, H such that 4k∈𝔊(G), π(G)=2, and 4k+ 2∈𝔊(H), π(H)=4. © 2009 Wiley Periodicals, Inc. J Graph Theory
Minimum C5‐saturated graphs
Authors: Chen Ya‐Chen 
Published: April 2009

AbstractA graph is C5‐saturated if it has no five‐cycle as a subgraph, but does contain a C5 after the addition of any new edge. We prove that the minimum number of edges in a C5 ‐saturated graph on n≥11 vertices is sat(n, C5)=⌈10(n−1)/7⌉−1 if n∈N0={11, 12, 13, 14, 16, 18, 20} and is ⌈10(n−1)/7⌉ if n≥11 and n∉N0. © 2009 Wiley Periodicals, Inc. J Graph Theory
Partial characterizations of circular‐arc graphs
Authors: Bonomo F. , Durán G. , Grippo L.N. , Safe M.D. 
Published: April 2009

AbstractA circular‐arc graph is the intersection graph of a family of arcs on a circle. A characterization by forbidden induced subgraphs for this class of graphs is not known, and in this work we present a partial result in this direction. We characterize circular‐arc graphs by a list of minimal forbidden induced subgraphs when the graph belongs to any of the following classes: P4 ‐free graphs, paw‐free graphs, claw‐free chordal graphs and diamond‐free graphs. © 2009 Wiley Periodicals, Inc. J Graph Theory 61: 289–306, 2009
“A brilliant and many‐sided personality”: Jessie Margaret Murray, founder of the Medico‐Psychological Clinic
Authors: Valentine Elizabeth R. 
Published: April 2009

AbstractThis paper outlines the life and career of Jessie Margaret Murray, the moving spirit behind the foundation of the Medico‐Psychological Clinic, the first public clinic in Britain to offer psychoanalytic therapy and training in psychoanalysis. Biographical details of Murray and her close friend and collaborator, Julia Turner, are presented, and possible routes by which the two women may have met are explored. Murray's role in the suffragist movement is described, as well as other networks and professional societies in which she was involved, in particular the British Society for the Study of Sex Psychology, and her relationship with Marie Stopes. An account is given of events leading up to the founding of the Clinic, its activities, Murray's death, and other factors contributing to its demise. Finally, the Clinic's heritage and implications of the personalities of Murray and Turner for understanding the subsequent development of psycho‐analysis in Britain are considered.
The synthesis of 3‐(β‐D‐ribofuranosyl)imidazo[4,5‐c] pyridazines
Authors: Halverson D. Michael , Castle Raymond N. 
Published: April 2009

Abstract7‐Chloro‐3‐(β‐D‐2,3,5‐tri‐O‐benzoylribofuranosyl)imidazo[4,5‐c] pyridazine (3), obtained from the condensation of 7‐chloro‐3‐trimethylsilylimidazo[4,5‐c] pyridazine (1) with 2,3,5‐tri‐O‐benzoyl‐D‐ribofuranosyl bromide (2), served as the percursor of 7‐chloro‐ (4), 7‐amino‐ (8), and 7‐mercapto‐3‐(β‐D‐ribofuranosyl)imidazo[4,5‐c] pyridazine (9). 3‐(β‐D‐ribofuranosyl)imidazo[4,5‐c] pyridazine (7) was obtained from 3‐(β‐D‐2,3,5‐tri‐O‐benzoylribofuranosyl)imidazo‐[4,5‐c]pyridazine (6). The site of ribosidation is based upon uv spectral comparisons with model methyl compounds. The assignment of the anomeric configuration is derived from pmr spectral data.
Solvent effect in the synthesis of 4‐carbamoyl‐3‐hydroxycoumarins
Authors: Lang S. A. , Cohen Elliott , Lovell F. M. 
Published: April 2009

AbstractA new synthesis of 4‐carbamoyl‐3‐hydroxycoumarin is reported. The synthesis of carbanilates of 3‐hydroxycoumarin and their novel rearrangement to the carboxamides is also described.
The reaction of some 4‐pyrones with activated isocyanates
Authors: Van Allan J. A. , Chang S. Chie , Reynolds G. A. 
Published: April 2009

AbstractThe pyrones, 2,6‐diphenyl‐4H‐pyran‐4‐one, flavone, and 2‐phenyl‐4H‐naphtho[2,1‐b]pyran‐4‐one reacted with activated isocyanates, such as trichloroacetyl isocyanate, giving 4‐trichloroacetylimino derivatives. These acylimino compounds underwent a slow reaction with a second mole of isocyanate to give a bisiminopyran.It is shown that carbonyl groups that are conjugated with electron‐releasing groups will react with activated isocyanates.
Chemical constitution and activity of bipyridylium herbicides. Part IX.N‐alkoxy quaternary salts of 4,4′bipyridyl
Authors: Fielden R. , Summers L. A. 
Published: April 2009

Abstract4,4′‐BipyridylN‐oxide and 4,4′‐bipyridylN,N'‐dioxide react with alkating agents to affordN‐alkoxyN'‐alkyl andN,N'‐dialkoxy diquaternary salts of 4,4′‐bipyridyl respectively. The diquaternary salts were very much less active as herbicides than paraquat. Unlike paraquat they cannot be regarded as reversible one electron transfer systems.
A novel oxidative reaction of 2,4,5‐triphenylpyrrole
Authors: Sprio Vincenzo , Petruso Salvatore , Lamartina Liliana 
Published: April 2009

AbstractThe effect of phenyl groups on the oxidation of 2,4,5‐triphenylpyrrole (I) has been investigated. By oxidation of 2,4,5‐triphenylpyrrolemagnesium bromide (II) with oxygen and of 2,4,5‐triphenylpyrrole (I) with potassium permanganate besides 2,4,5,2′,4′,5′‐hexaphenyl‐3,3′‐bi‐pyrrole (III) another product, which has been assigned the 1,6‐dihydro‐2,3,4,5,6a‐pentaphenylbenzo[g]pyrrole[3,2‐e]indole (IV) structure, was obtained. The behaviour of IV toward further oxidation and the spectroscopic data (ir, nmr, ms) were in good agreement with the assigned structures.
New syntheses of condensed heterocycles from isoxazole derivatives. IV. Benzimidazol‐2(3H)ones and 1‐H‐1,5‐benzodiazepin‐2(3H)one
Authors: Ajello Enrico , Migliara Onofrio , Ceraulo Leopoldo , Petruso Salvatore 
Published: April 2009

AbstractA new synthesis of the title compounds is described. Catalytic hydrogenation of 3‐R‐5‐R'‐2‐nitro‐4‐isoxazolecarboxanilides (III) yield compounds IV which were cyclized by refluxing in toluene with traces of p‐toluenesulphonic acid. In contrast to IVa which gave directly 3‐acetyl‐4‐phenyl‐1H‐1,5‐benzodiazepin‐2(3H)one (Va), compounds IVb and IVc afforded instead the 1‐substituted benzimidazolones VIb and VIc, respectively. The structure of VIa, b, and c, VIIb and VIIc has been elucidated by chemical and spectral means including mass and nmr spectra.
Thio‐I ehromannones 5,8‐disubstituées et synthèses dans la série du thiéno[4,3,2‐de] thiochromanne
Authors: Ricci Adolfo , Balucani Dante , Grandolini Giuliano 
Published: April 2009

AbstractDans le but d'aceéder à la structure thiéno [4,3,2‐de] thicohromanne nous avons synthétisé divers dérivés disubstitués en 5,8 de la thio‐l chromannone‐4. Les produits ainsi obtenus et les intermédiaires de synthèse ont été examinés en résonance magnétique nucléaire. Les structures out été confirmées soit par cette voie, soit par voie chimique pour aboutir à des composés déjà décrits.
Preparation of α,ω‐ditriazinylperfluoroalkane derivatives
Authors: Kim Yung K. , Grindahl George A. , Greenwald John R. , Pierce Ogden R. 
Published: April 2009

AbstractThe synthesis of 2‐oxa and 2‐thiaperfluoroglutaric acids and their corresponding ethyl esters, amides, nitriles, acid chlorides, and also 2‐thiaperfluoroglutaric anhydride are described. These compounds were prepared as precursors to α,ω‐ditriazinylperfluoroalkane derivatives containing a heteroatom in the perfluoroalkylene chain. The ditrazinylpropanes were prepared most satisfactorily from the diacid chlorides rather than the dinitriles.
Macrocyclic sulfide syntheses: A review
Authors: Bradshaw Jerald S. , Hui Joseph Y. K. 
Published: April 2009

AbstractThe syntheses of various macrocyclic sulfides are reviewed. Tables containing information on hundreds of compounds are included. The types of cyclic compounds reviewed include: macrocyclic aliphatic dithioethers, macrocyclic mercaptals and mercaptoles, macrocyclic polysulfides, dithiacyclophanes, tris‐bridged polythiacyclophanes, dithia[2,6]pyridinophanes, thiophene macrocycles, and macrocyclic polyether sulfides.
Synthesis of antifols related to 2,4‐diamino‐6,7‐dihydro‐5H‐pyrrolo[3,4‐d] pyrimidine. Enhancement of antiparasitic selectivity by nitrogen‐linked mono‐ and dichlorobenzoyl groups or the 3,4–dichlorophenylthiocarbamoyl group
Authors: Southwick Philip L. , Amarnath Venkataraman , Madhav R. 
Published: April 2009

AbstractImproved procedures have been developed for the synthesis of 2,4‐diamino‐6,7‐dihydro‐5H‐pyrrolo[3,4‐d]pyrimidine (2a), its 7‐mcthyl derivative (2b), and 6‐(chloro‐substituted phenyl) derivatives of 2,4‐diamino‐6,7‐dihydro‐5H‐pyrrolo[3,4‐d]pyritnidine (4). Direct acylation of compounds 2a or 2b with acid chlorides or mixed anhydrides derived from chloro‐substituted benzoic or cinnamic acids gave 6‐(chloro‐substituted benzoyl or cinnamoyl) derivatives. Lithium aluminum hydride reduction of 6‐(chloro‐substituted benzoyl) derivatives under controlled conditions permitted preparation of 6‐(chloro‐substituted benzyl) derivatives (3). Compound 2a also reacted with aryl isothiocyanates to yield 6‐arylthiocarbamoyl derivatives. Antimalarial assays for in vivo activity against murine malaria (P. berghei) and avian malaria (P. gallinaceum) revealed that a somewhat enhanced in vivo antiparasitic effect above that of parent compound 2a without any evident increase in host toxicity was conferred by introduction of certain of the 6‐chloro‐substituted benzoyl groups or the 6‐(3,4‐dichlorophenylthiocarbamoyl) group. Corresponding 6‐(chloro‐substituted benzyl) derivatives more frequently displayed host toxicity.