Azulene as an ingredient for visible-light- and stimuli-responsive photoswitches.

The azulene molecule features a unique combination of optical, luminescence, and stimuli-responsive properties. This makes the azulene motif a promising functional group to be introduced in photoswitches. Recent challenges in the field of photochromic compounds require the development of new approaches to molecules that are switched by visible light (400-760 nm), are proton responsive and have advanced luminescent properties. Merging azulene with photoswitches opens prospects for fulfilling these requirements. Herein, we highlight recent results on the application of this hydrocarbon motif in various photochromic systems, such as stilbenes, diarylethenes, and azobenzenes.

Route for Conversion of Furfural to Ethylcyclopentane.

A method for conversion of furfural, widely available platform chemical from biomass, to ethylcyclopentane, is reported. Ethylcyclopentane is a cyclic alkane with a relatively high octane number (RON 67, bp 103 °C) and could potentially serve as a drop-in biofuel. The synthetic route includes a transformation of furfural to 1-(furan-2-yl)propan-1-ol that is further subjected to Piancatelli rearrangement to give 5-ethyl-4-hydroxycyclopent-2-en-1-one. The subsequent hydrodeoxygenation affords ethylcyclopentane in 48% isolated yield.

Antiretroviral (HIV-1) activity of azulene derivatives.

The antiretroviral activity of azulene derivatives was detected for the first time. A series of eighteen diversely substituted azulenes was synthesized and tested in vitro using HIV-1 based virus-like particles (VLPs) and infectious HIV-1 virus in U2OS and TZM-bl cell lines. Among the compounds tested, the 2-hydroxyazulenes demonstrated the most significant activity by inhibiting HIV-1 replication with IC50 of 2-10 and 8-20 µM for the VLPs and the infectious virus, respectively. These results indicate that azulene derivatives may be potentially useful candidates for the development of antiretroviral agents.

Evaluation of carbohydrates and lignocellulosic biomass from different wood species as raw material for the synthesis of 5-bromomethyfurfural.

The influence of different parameters on the conversion of carbohydrates and biomass into the potential biofuel intermediate 5-bromomethylfurfural (BMF) has been studied. Our optimized conditions avoid the use of lithium salt additives, making this method cheaper and environmentally more benign compared to previously reported methods. Different wood species and their potential as a raw material in BMF and furfural production have also been evaluated. In addition, we report a very simple and efficient procedure for conversion of 5-hydroxymethylfurfural (HMF) into BMF or 5-chloromethylfurfural (CMF).

Use of polyanions for alkylation of hydrazine derivatives.

Alkylation of hydrazine and its derivatives still remains a quite complicated task. The novel method utilizing the polyanion strategy is reported. Formation and use of trianion for alkylation of hydrazine derivatives is first reported. Described method provides fast and convenient access to multialkylated derivatives. Scope and limitations of new method are also investigated.

Efficient methodology for selective alkylation of hydrazine derivatives.

Formation and use of a nitrogen dianion for selective hydrazine alkylation is reported. The scope and limitations of a new method were demonstrated. The novel method provides fast and easy access to substituted hydrazines, which are widely used as drugs, pesticides, and precursors for a variety of compounds in organic synthesis. [reaction: see text]