Mini-Reviews in Organic Chemistry - Volume 13, Issue 3, 2016

Katrin Groebke, Christopher Blackburn, and Hugues Bienayme have individually reported a three-component-reaction (3CR) among 2-aminopyridine, aldehyde, and isocyanide to afford imid- azo[1,2-a]pyridine in 1998. This multicomponent reaction was so-called as Groebke-Blackburn- Bienayme reaction (abbreviated as Groebke 3CR). The Groebke 3CR led to a convenient way for ac- cessing to a great abroad of imidazo[1,2-a]-contained N-heterocycles, which were believed to be anti- cancer, antibacterial, and antimalarial drugs or to be inhibitors for epoxide hydrolase, 5-lipoxygenase, and non-nucleoside reverse transcriptase, etc. The potent applications of the imidazo[1,2-a]-contained N-heterocycles triggered the research enthusiasm on the Groebke 3CR, including the expanding of the substrates, the changing of the substrates, and the exploring of the catalytic process. In particular, other substrates instead of 2-aminopyridine were employed in the Groebke 3CR, leading to the formation of different N-heterocycles for screening pharmacological activities. Taken collectively, more details of the Groebke 3CR should be revealed in the following re- searches in order to produce much more N-polyheterocyclic candidates for finding novel drugs.

With the requirements of green and high-selectivity synthesis, organocatalytic asymmetric transformations of achiral substrates into specific enantiomers or diasteroisomers have gained enormous significance from academic, industrial and environmental perspectives. These transformations are usually catalyzed by axially dissymmetric small chiral organic molecules or by organic compounds bearing chiral center(s). The stereochemical outcome of the enantiomerically or diastereomerically enriched product is normally governed by weak non-covalent hydrogen-bond interactions of the electrophilic/nucleophilic substrates with potent hydrogen bond-donor and/or acceptor functional groups present on the rigid chiral backbone of the organic catalyst. The current review intends to cover recent development in the design of chiral cinchona alkaloids bearing multiple functional groups and their role in organocatalytic asymmetric synthesis.

The following article has been retracted on the request of the Authors Dr. Kapil Arya and Dr. Dhanraj T. Masram entitled 128;œConversion of Sugar to Aldonic Acids: An Important Industrial Precursor128;; pub-lished in Mini-Reviews in Organic Chemistry, vol.13, no. 3; Pp. 198-205128;. The above article contains a graphical abstract which was used by the authors without soliciting per-mission from the License Compliance UAE, which represents a copyright violation. Bentham Science apologizes to the readers of the journal for not detecting this omission during the publishing process. We thank Mr. Ameer Alian for bringing this breach of conduct to our attention. BENTHAM SCIENCE DISCLAIMER It is a condition of publication that manuscripts submitted to this journal have not been published and will not be simultaneously submitted or published elsewhere. Furthermore, any data, illustration, structure or table that has been published elsewhere must be reported, and copyright permission for reproduction must be obtained. Plagiarism is strictly forbidden, and by submitting the article for publication the authors agree that the publishers have the legal right to take appropriate action against the authors, if plagiarism or fabricated information is discovered. By submitting a manuscript the authors agree that the copyright of their article is transferred to the publishers if and when the article is accepted for publication.

Atropisomeric biaryl compounds are an attractive target in organic chemistry due to their abundance in nature and their utility as ligands in catalysis. Among the methods available for their synthesis, the use of chiral tethers offers very high levels of stereocontrol. In this article, we review the application of molecular tethers in controlling axial chirality across a range of different ligands and natural products.

Because of its natural occurrence and novel biological activity, interest in the investigation of (1R,2S)-2-aminocyclopentanecarboxylic acid (cispentacin) has rapidly increased. Since its activity against Candida albicans, C. neoformans, and a systemic C. infection, a number of enzymatic strategies for its preparation in enantiomerically pure form have been developed. Structural optimization of cispentacin resulted in the synthesis of derivatives such as (1R,2S)-2-amino-4-methylenecyclopentanecarboxylic acid with even superior efficacy in view of antifungal activity. Not only cispentacin itself and some of its small-molecule derivatives have been described as molecules of interesting bioactivity but it was also found that the cyclopentane β-amino acid moiety may be a key element of larger molecules with important pharmacological properties, such as the antibiotic amipurimycin. The present review is intended to give a brief insight into the most relevant enzymatic strategies for the synthesis of 25-year-old cispentacin and its close analogues containing the cispentacin subunit. These methods are classified as indirect or direct strategies. Some practical details for the preparative-scale resolution of a selected racemate furnishing cispentacin with excellent ee and very good yield are highlighted at the end of this overview.

Chagas disease is a neglected disease caused by Trypanosoma cruzi (T. cruzi) that remains a serious public health problem in Latin America since there are approximately 7 million infected peo- ple, making it a matter of worldwide concern. Advances in new therapeutic strategies to combat Cha- gas disease have been scarce over the last decades. Efforts have been made to explore T. cruzi en- zymes as potential therapeutic targets. Inhibitors that act on enzymes such as triose phosphate isomer- ase (TIMTc), glyceraldehyde 3-phosphate dehydrogenase (GAPDHTc), trypanothione reductase (TR), cruzipain, squalene synthase (SQSTc), farnesyl pyrophosphate synthase (FPPSTc) and sterol 14 a-demethylase (CYP51Tc) of T. cruzi have been studied to develop selective inhibitors that interrupt the lifecycle of T. cruzi. These selected drug targets are part of indispensable T. cruzi survival systems such as the glycolysis pathway, cellular detoxification, the host adhesion complex and sterol synthesis pathways, which exhibit relevant features useful in the design of selective inhibitors that may be use- ful for treating Chagas disease. This review discusses recent progress in the exploration of these enzymes as therapeutic targets and their relevant structural features to develop new drugs against American trypanosomiasis.