Mini-Reviews in Organic Chemistry - Volume 14, Issue 5, 2017

Fluorinated medicines have become research emphasis in the fields of pesticides and medicines due to their advanced properties. Trifluoroacetoacetate (TFAAE) is an important intermediate for the synthesis of pesticide, medicine and other fluorine compounds. As a useful building block containing trifluoromethyl, TFAAE is widely used in the synthesis of heterocyclic drugs, insecticides and herbicides. In this paper, the preparation methods of TFAAE and the advanced applications in agrochemicals and medicines with fluorine are introduced in detail

Considering the diverse applications and importance of DNA topoisomerases II (TOP II) inhibitors in biological systems, it is vital to understand the fundamental organic chemistry of these inhibitory agents through various synthetic strategies and it is crucial for further developments of the same. Many of the reported TOP II inhibitors are associated with extreme structural complexities and require multi-step synthetic routes providing difficulties towards their preparation and modifications. The present work describes the synthetic protocols for a diverse array of candidates relating to both TOP II poisons and catalytic inhibitors which may be useful for further synthetic developments.

2,3-Dichloro-1,4-naphthoquinone is a special naphthoquinone with four electrophilic sites, useful for applications in organic synthesis and preparation of a diverse new compounds, such as 2,3-substituted derivatives and heterocycles, including those with the core naphthoquinone structure fused. It has also been used for the preparation of compounds for evaluation against several biological targets. This review will describe the most recent applications of 2,3-dichloro-1,4-naphthoquinone in organic synthesis.

Harmful algae blooms (HABs) involving Prymnesium parvum (Golden algae) is a worldwide fish killing event, seriously threatening the aquaculture industry and aquatic ecosystems. HABs frequently occur in natural reservoirs such as natural lakes which receive large numbers of visitors throughout the year. As a result, large amounts of Ultra-Violet (UV) chemical filters (the active ingredient of sunscreen products) are released to the lake due to swimming or sun-bathing, which add synergic environmental stresses on the Lake ecosystem. Prymnesium parvum is associated with the production of potent toxins (prymnesins) known for fish kills around the world. The molecular structure of prymnesins possesses both chlorine and nitrogen groups which can actively participate in photochemical reactions with organic and inorganic UV filter molecules. Consequently, reactive oxygen species (ROS) and chlorinated toxins can be potentially formed, leading to fish kill and dangerous biomagnification of reactive molecules in humans through dietary consumption of seafood. In this brief review, we discussed some possible mechanisms for the formation of toxic compounds due to the presence of UV filters and chlorine-containing compounds, using a lake in central Texas as an example. While the properties of various biotoxins released by P. parvum in a HAB event have been investigated, this is the first time that the environmental concern of the toxic behavior of reactive UV filters in a HAB event has been highlighted. Significant new insights are needed for the connections between harmful algae blooms and the accumulation of UV filters in water bodies so that appropriate policies can be established to protect the marine environment.

Azaflavanones are synthetic aza-analogues of flavanones possessing several biological interests, especially as anticancer. Since individual enantiomers of azaflavanones showed different anticancer activities, the development of asymmetric routes to access this class of compounds has appeared in the literature. This review shows the different approaches for the enantioselective synthesis of azaflavanones based on asymmetric catalysis.

Organic thioether compounds had found extensive applications in the field of medicine, biology, agriculture, optical material and so on. The protocols synthesizing thioethers have always been an attractive interest to researchers. So far, various preparation methods involving diverse catalysts and promote reagents have been reported. A wide scope of newly published vital articles referring reactions of organic halides, alkenes, arenes, heteroaromatics and organic borides with sulfur source thiols, thiophenols, thioamides, potassium xanthate, potassium thiocyanate, elemental sulfur, sodium thiomethoxide, sodium sulfide, carbon disulphide, disulfides, sulfonyl hydrazides, AgSCF3, CuSCF3 with transition metal complexes catalyzation or with metal free method are comprehensively summarized in this review.