Stereoisomerism

Publication Title: 
Journal of Chemical Information and Modeling

We report the development and implementation of a cheminformatics tool which aids in the design of compounds during exploratory chemistry and lead optimization. The Heterocyclic Regioisomer Enumeration and MDDR Search (HREMS) tool allows medicinal chemists to build greater structural diversity into their synthetic planning by enabling a systematic, automated enumeration of heterocyclic regioisomers of target structures.

Author(s): 
Tyagarajan, Sriram
Lowden, Christopher T.
Peng, Zhengwei
Dykstra, Kevin D.
Sherer, Edward C.
Krska, Shane W.
Publication Title: 
Journal of Asian Natural Products Research

Two new triterpenoids, termichebuloside A (1), an unusual dimeric triterpenoid saponin, and termichebulolide (2), an oleanolic acid-type lactone, along with 11 known triterpenoids, were isolated from MeOH extract of the barks of Terminalia chebula. The structures of 1 and 2 were elucidated to be arjunglucoside I-(3-O-19',23-O-19')-18,19-seco-19-hydroxyarjunglucoside I (1) and 2?,3?,23-trihydroxyolean-11,13(18)-dien-28,19?-olide (2), respectively, on the basis of spectroscopic evidences and biogenetic consideration.

Author(s): 
Zhang, Chao
Jiang, Kun
Qu, Shi-Jin
Zhai, Yi-Ming
Tan, Jun-Jie
Tan, Chang-Heng
Publication Title: 
Annual Review of Nutrition
Author(s): 
Emken, E. A.
Publication Title: 
Life Sciences

Ketamine is a racemic mixture containing equal parts of (+)-ketamine and (-)-ketamine. The ketamine enantiomorphs are different in anesthesia and psychic emergence reactions after anesthesia. Therefore, (+)-ketamine was compared with racemic ketamine in a number of randomized studies in volunteers and patients. However, their relations remain controversial. In the present studies, the psychic emergence reactions after injection of (+/-)-ketamine and (+)-ketamine were compared in mice.

Author(s): 
Liu, Jing
Ji, Xing-Quan
Zhu, Xing-Zu
Publication Title: 
Journal of Veterinary Pharmacology and Therapeutics

The aim of this study was to determine the relative potency of racemic ketamine and S(+)-ketamine for the hypnotic effect and to evaluate the clinical anesthesia produced by equianesthetic doses of these two substances in dogs. One hundred and eight dogs were allocated in groups R2, R2.5, R3, R6, R9, R12, S2, S2.5, S3, S6, S9, and S12, to receive by intravenous route 2, 2.5, 3, 6, 9, and 12 mg/kg of ketamine or S(+)-ketamine, respectively. A dose-effect curve was drawn with the dose logarithm and the percentage of dogs that presented hypnosis in each group.

Author(s): 
Duque, J. C.
Oleskovicz, N.
Guirro, E. C. B. P.
Valadão, C. a. A.
Soares, V. E.
Publication Title: 
Anesthesiology

BACKGROUND: R-etomidate possesses unique desirable properties but potently suppresses adrenocortical function. Consequently, efforts are being made to define structure-activity relationships with the goal of designing analogues with reduced adrenocortical toxicity. The authors explored the pharmacological impact of modifying etomidate's chiral center using R-etomidate, S-etomidate, and two achiral etomidate analogues (cyclopropyl etomidate and dihydrogen etomidate).

Author(s): 
Pejo, Ervin
Santer, Peter
Jeffrey, Spencer
Gallin, Hilary
Husain, S. Shaukat
Raines, Douglas E.
Publication Title: 
Bioorganic & Medicinal Chemistry

From 9-substituted DHA, several new artemisinin-derived C-10 acetal ethers and esters were prepared with either a 9-fluoro or a 9-sulfonyl substituent. The very strong inductive electron-withdrawing C-9 substituent is shown to retard considerably C-10 ionization (acid-promoted etherification) of 9-fluoro-DHA and 9-sulfonyl-DHA.

Author(s): 
Posner, Gary H.
Maio, William A.
Kalinda, Alvin S.
Publication Title: 
The Journal of Biological Chemistry

At some point during biosynthesis of the antimalarial artemisinin in glandular trichomes of Artemisia annua, the Delta11(13) double bond originating in amorpha-4,11-diene is reduced. This is thought to occur in artemisinic aldehyde, but other intermediates have been suggested. In an effort to understand double bond reduction in artemisinin biosynthesis, extracts of A. annua flower buds were investigated and found to contain artemisinic aldehyde Delta11(13) double bond reductase activity.

Author(s): 
Zhang, Yansheng
Teoh, Keat H.
Reed, Darwin W.
Maes, Lies
Goossens, Alain
Olson, Douglas J. H.
Ross, Andrew R. S.
Covello, Patrick S.
Publication Title: 
Journal of Medicinal Chemistry

Novel dicationic triazoles 1-60 were synthesized by the Pinner method from the corresponding dinitriles, prepared via the copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC). The type and the placement of cationic moieties as well as the nature of aromatic substituents influenced in vitro antiprotozoal activities of compounds 1-60 against Trypanosoma brucei rhodesiense, Plasmodium falciparum, and Leishmania donovani and their cytotoxicity for mammalian cells. Eight congeners displayed antitrypanosomal IC(50) values below 10 nM. Thirty-nine dications were more potent against P.

Author(s): 
Bakunov, Stanislav A.
Bakunova, Svetlana M.
Wenzler, Tanja
Ghebru, Maedot
Werbovetz, Karl A.
Brun, Reto
Tidwell, Richard R.
Publication Title: 
Molecules (Basel, Switzerland)

Since its identification in the early 1970s, artemisinin, as well as semi-synthetic derivatives and synthetic trioxanes, have been used in malaria therapy. Reduction of artemisinin by NaBH4 produced dihydroartemisinin (DHA), and yielded a new stereochemically labile centre at C-10, which, in turn, provided two interconverting lactol hemiacetal epimers (namely alpha and beta), whose rate of interconversion depends on buffer, pH, and solvent polarity.

Author(s): 
D'Acquarica, Ilaria
Gasparrini, Francesco
Kotoni, Dorina
Pierini, Marco
Villani, Claudio
Cabri, Walter
Di Mattia, Michela
Giorgi, Fabrizio

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