Caffeine and Purine Derivatives: A Comprehensive Review on the Chemistry, Biosynthetic Pathways, Synthesis-Related Reactions, Biomedical Prospectives and Clinical Applications.

Caffeine and purine derivatives represent interesting chemical moieties, which show various biological activities. Caffeine is an alkaloid that belongs to the family of methylxanthine alkaloids and it is present in food, beverages, and drugs. Coffee, tea, and some other beverages are a major source of caffeine in the human diet. Caffeine can be extracted from tea or coffee using hot water with dichloromethane or chloroform and the leftover is known as decaffeinated coffee or tea. Caffeine and its derivatives were synthesized via different procedures on small and large scales. It competitively antagonizes the adenosine receptors (ARs), which are G protein-coupled receptors largely distributed in the human body, including the heart, vessels, brain, and kidneys. Recently, many reports showed the effect of caffeine derivatives in the treatment of many diseases such as Alzheimer's, asthma, parkinsonism, and cancer. Also, it is used as an antioxidant, anti-inflammatory, analgesic, and hypocholesterolemic agent. The present review article discusses the synthesis, reactivity, and biological and pharmacological properties of caffeine and its derivatives. The biosynthesis and biotransformation of caffeine in coffee and tea leaves and the human body were summarized in the review.

Synthesis and Anticancer Activity of Novel Chromene Derivatives, Chromeno[2,3-d][1,3]Oxazines, and Chromeno[2,3-d]Pyrimidines.

BACKGROUND: Several chromene derivatives have a wide variety of biological and pharmacological activity. They had anticancer activity, antimicrobial activity, antituberculosis activity, anticonvulsant activity, antidiabetic activity, antichlolinesterase activity, and inhibitor of monoamine oxidase activity. The above-mentioned activities directed us to synthesize novel chromene derivatives, chromeno[2,3-d][1,3]oxazines, and chromeno[2,3-d]pyrimidines. The starting material was 2- amino-8-(2-chlorobenzylidene)-4-(2-chlorophenyl)-5,6,7,8-tetrahydro-4H-chromene-3-carbonitrile. METHODS: Several novel chromene derivatives had been synthesized. Compound 1 reacted with carbon disulfide, and ethyl chloroformate to afford chromene derivatives 2, 3. Chromene derivative 3 reacted with hydrazine dydrate to give compound 4. Chromene derivative 1 reacted with acetic acid and sulphuric acid to produce compounds 5, and 6. Amino derivative 5 reacted with chloroacyl derivative to afford compounds 7a-c which cycalized in dry xylene to afford compounds 8a-c. Chromene derivative 8a reacted with hydroxyl amine to afford compound 9. RESULTS: The structures of novel synthesized chromene derivatives had been confirmed using mass spectroscopy, infrared spectroscopy, nuclear magnetic resonance spectroscopy, and elemental analysis. Most of the prepared compounds were screened against liver cancer cell lines (HepG-2), human colon cancer cell lines (HT-29), and breast adenocarcinoma cell lines (MCF-7). Chromene derivative 2 had anticancer activity against human colon cancer cell lines (HT-29) higher than the reference drug doxorubicin. The rest of the tested compounds had anticancer activity against human colon cancer cell lines (HT-29) lower than that of the reference drug doxorubicin. Chromene derivative 5 had anticancer activity against liver cancer cell lines (HepG-2) higher than the reference drug doxorubicin. CONCLUSION: Several chromene derivatives had been synthesized and their structures had been confirmed using different spectroscopic techniques. Some of the chromene derivatives that were screened against different cancer cell lines showed promising anticancer activity higher than the reference standard drug. For example, chromene derivative 2 had anticancer activity against human colon cancer cell lines (HT-29) higher than the reference drug doxorubicin. Chromene derivative 5 had anticancer activity against liver cancer cell lines (HepG-2) higher than the reference drug doxorubicin. Chromene derivative 6 had anticancer activity against breast adenocarcinoma cell lines (MCF-7) higher than the standard drug.

Novel allyl-hydrazones including 2,4-dinitrophenyl and 1,2,3-triazole moieties as optical sensor for ammonia and chromium ions in water.

It is critical to take safety action if carcinogenic heavy metals and ammonia can be detected quickly, cheaply, and selectively in an environmental sample. As a result, compound 4a [4-(1-(2-(2,4-Dinitrophenyl)hydrazineylidene)-3-(naphthalen-2-yl)allyl)-5-methyl-1-phenyl-1 H-1,2,3-triazole] and compound 4b [4-(1-(2-(2,4-Dinitrophenyl)hydrazineylidene)-3-(naphthalen-2-yl)allyl)-1-(4-fluorophenyl)-5-methyl-1 H-1,2,3-triazole] were prepared. The aldol condensation process of 4-acetyl-1,2,3-triazoles 1a,b (Ar = C6H4; 4-FC6H4) with 2-naphthaldehyde yields 1-acetyl-1,2,3-triazoles 1a,b (Ar = C6H4; 4-FC6H4) (5-methyl-1-aryl-1 H-1,2,3-triazol-4-yl) -3-(naphthalen-2-yl)prop-2-en-1-ones 3a,b with a yield of around 95%. The target compounds 4a,b are obtained in around 88% yield by condensation of 3a,b with (2,4-dinitrophenyl)hydrazine in a refluxing acidic medium. Compounds 4a,b exhibited possible colorimetric detection for chromium ion in the range of 0-14 ppm and ammonia in the range of 0-20 ppm. As a result, this research suggests that strong electron-withdraw groups in related probes can improve anion detection ability, while the conjugation effect should also be considered while building structures.

Interaction of small molecules with polynucleotide repeats and frameshift site RNA.

This mini-review describes the interaction between small molecules and RNA, in addition to its application either in treating RNA-associated diseases or detecting target molecules. In the case of RNA-associated disease treatment, the designed small molecules interact with RNA sites, forming adducts and providing successful therapeutic strategies over oligonucleotides. On the other hand, synthetically designed RNA moieties (aptamers) interact with target molecules like toxins, drugs, hormones; these interactions are useful in the detection, quantification or separation of these target moieties.