Trazodone, a well-known antidepressant drug widely used throughout the world, works as a 5-hydroxytryptamine (5-HT₂) and α₁-adrenergic receptor antagonist and a serotonin reuptake inhibitor. Our research aimed to develop a new method for the synthesis of trazodone and its derivatives. In the known methods of the synthesis of trazodone and its derivatives, organic and toxic solvents are used, and the synthesis time varies from several to several dozen hours. Our research shows that trazodone and its derivatives can be successfully obtained in the presence of potassium carbonate as a reaction medium in the microwave field in a few minutes. As a result of the research work, 17 derivatives of trazodone were obtained, including compounds that exhibit the characteristics of 5-HT_1A receptor ligands. Molecular modeling studies were performed to understand the differences in the activity toward 5-HT_1A and 5-HT_2A receptors between ligand 10a (2-(6-(4-(3-chlorophenyl)piperazin-1-yl)hexyl)-[1,2,4]triazolo[4,3-a]pyridin-3(2H)-one) (5-HT_1A K_i = 16 nM) and trazodone. The docking results indicate the lack of the binding of ligand 10a to 5-HT_2AR, which is consistent with the in vitro studies. On the other hand, the docking results for the 5-HT_1A receptor indicate two possible binding modes. Crystallographic studies support the hypothesis of an extended conformation.

In the pharmacotherapy of schizophrenia, there is a lack of effective drugs, and currently used agents cause a large number of side effects. The D₂, 5-HT_1A, 5-HT_2A receptors are among the most important receptor targets in the treatment of schizophrenia, but antagonism at 5-HT₆ and 5-HT₇ receptors may bring about additional improvement of cognitive functions. However, doubt exists regarding the importance of 5-HT₇R in the pharmacotherapy. In 2010, lurasidone (with high affinity for D₂, D₃, 5-HT_1A, 5-HT_2A, 5-HT₇ receptors) was approved for the treatment of schizophrenia. Due to the efficacy of the mentioned drug and doubts related to the role of 5-HT₇R, we decided to obtain compounds with an activity profile similar to that of lurasidone, but with the reduced affinity for 5-HT₇R and increased affinity for 5-HT₆R. For this purpose, we chose aflexible hexyl derivative of lurasidone (2-(6-(4-(benzo[d]isothiazol-3-yl)piperazin-1-yl)hexyl)hexahydro-1H-4,7-methanoisoindole-1,3(2H)-dione 1a) as a hit structure. After molecular modeling, we modified it, in the area of the arylpiperazine and imide group, using the moieties found in other known CNS drugs. We received the compounds in accordance with the previously developed method of ecological synthesis in the microwave radiation field. Among the obtained compounds, N-(6-(4-(benzo[d]isothiazol-3-yl)piperazin-1-yl)hexyl)naphthalene-sulfonamides 1v and 1w were distinguished as multifunctional ligands showing increased affinity for 5-HT₆R, and 2-(6-(4-(benzo[d]isothiazol-3-yl)piperazin-1-yl)hexyl)-[1,2,4]triazolo[4,3-a]pyridin-3(2H)-one 1i - a multifunctional ligand showing moderate affinity for 5-HT₆R and threefold lower for 5-HT₇R. In the paper, we discuss some of the observed dependencies regarding 5-HT₆/5-HT₇R affinity using molecular docking methods.

Phase transfer catalysis (PTC) is an excellent possibility in the synthesis of organic compounds as it allows the reactions to be carried out under the conditions of green chemistry, while maintaining high yields and selectivity. The great advantage of these reactions is also the possibility of carrying out the reactions not only under conventional conditions, but also mechanochemically in solvent-free processes. Bearing this in mind, we decided to develop a new method for the synthesis of known biologically active compounds from the group of long-chain arylpiperazines (LCAPs). The first mortar trials were very promising and prompted us to carry out a series of ball mill reactions. One of the technological problems that we encountered while conducting reactions in the ball mill was the difficulty in extracting the post-reaction mixture. We tested the effects of additives improving the insulation of the product, such as, e.g., starch, zeolites, and silica. Research has proven that with appropriate process conditions using TBAB as a catalyst and in the presence of potassium carbonate and a small amount of Zeolite ZSM5 or silica, aripiprazole can be obtained with a yield of 90% in just five minutes. The obtained results are very promising and it is worth considering them as an alternative to the synthesis of other compounds from the LCAPS group.

1,3,5-triazine derivatives are useful compounds with potential applications in various branches of chemical industry, including pharmaceutical chemistry, cosmetic chemistry, photochemistry, and organic chemistry. Due to the growing environmental requirements on conducting efficient, economical, and safe syntheses, development of new methods for synthesizing organic compounds is highly desirable. In this publication, we present a protocol for the synthesis of 1,3,5-triazine derivatives using a sonochemical approach. In as little as 5 min, it is possible to obtain most of the investigated compounds with a yield of over 75%. An undeniable advantage of this method, besides its short time, is the use of water as the solvent. Furthermore, we provide examples that the sonochemical method may be more versatile than the competing microwave method. Analysis conducted using the DOZN^TM 2.0 tool revealed that in terms of the 12 principles of green chemistry, the developed sonochemical method is 13 times "greener" than the classical one. Additionally, it has been demonstrated that the investigated molecules are attractive for their application as drug-like compounds.