Chalcone

Molecular Formula : C₁₅H₁₂O

Molar mass : 208.26 g mol⁻¹ 

Melting Point : 55–57 °C

Boiling Point : 345–348 °C 

Chalcone is an aromatic ketone and an enone that forms the central core for a variety of important biological compounds, which are known collectively as chalcones or chalconoids. The name “Chalcones” was given by Kostanecki and Tambor. These compounds are also known as benzalacetophenone or benzylidene acetophenone. In chalcones, two aromatic rings are linked by an aliphatic three carbon chain. Chalcone bears a very good synthon so that variety of novel heterocycles with good pharmaceutical profile can be designed.

Chalcones are -unsaturated ketone containing the reactive ketoethylenic group –CO-CH=CH. These are coloured compounds because of the presence of the chromophore -CO-CH=CH-, which depends in the presence of other auxochromes.

synthesis

A variety of methods are available for the synthesis of chalcones, the most convenient method is the one that involves the Claisen-Schmidt condensation of equimolar quantities of a substituted acetophenone with substituted aldehydes in the presence of aqueous alcoholic alkali.10-17 In the Claisen-Schmidt reaction, the concentration of alkali used, usually ranges between 10 and 60 %.18-19 The reaction is carried out at about 50 oC for 12-15 hours or at room temperature for one week. But various condensing agent can used in synthesis of chalcone.

Theobromine

   

Formula: C₇H₈ N₄O₂

Synonyms

3,7-dimethylxanthine, 3,7-dihydro-3,7-dimethyl-1H-purine-2,6-dione

What is Theobromine?

Theobromine (theobromide), also known as xantheose, is a bitter alkaloid of the cacao plant, with the chemical formula C₇H₈N₄O₂. It is in the methylxanthine class of chemical compounds, which also includes the similar compounds theophylline and caffeine. (In caffeine, the only difference is that the NH group of theobromine is an N-CH₃ group.) Despite its name, the compound contains no bromine—theobromine is derived from Theobroma, the name of the genus of the cacao tree. They just tagged on an '-ine' suffix given to basic nitrogenous molecules. The named Theobroma is built from the Greek roots theo- ('God") and –brosi ('food'), meaning "food of the gods.

Theobromine is a slightly water-soluble (330 mg/L), crystalline, bitter powder; the colour has been listed as either white or colourless. It has a similar, but lesser, effect than caffeine in the human nervous system, making it a lesser homologue. Theobromine is categorized as a dimethyl xanthine.

 Distribution

 
 

Theobromine is the primary alkaloid found in cocoa and chocolate. Cocoa powder can vary in the amount of theobromine, from 2% theobromine to at least 10%, usually having higher concentrations in dark than milk chocolate. Theobromine can also be found in small amounts in the kola nut (1.0-2.5%), the guarana berry, Ilex guayusa, Ilex paraguariensis (yerba mate), and the tea plant. In general, theobromine levels are higher in dark chocolates (approximately 10 g/kg) than in milk chocolates (1-5 g/kg). Higher quality chocolate tends to contain more theobromine than lower quality chocolate. Cocoa beans naturally contain approximately 300-1200 mg/ounce theobromine.

 

Theobromine poisoning

Serious poisoning happens in domestic animals, which metabolize theobromine much more slowly than humans, and can easily consume enough chocolate to cause chocolate poisoning. The most common victims of theobromine poisoning are dogs, for which it can be fatal. The toxic dose for cats is even lower than for dogs. However, cats are less prone to eating chocolate since they are unable to taste sweetness. Theobromine is much less toxic to rats and mice, due to their relative genetic similarity to primates.

In dogs, the half-life of theobromine is 17.5 hours, so in severe cases clinical symptoms of theobromine poisoning can persist for 72 hours. Medical treatment performed by a veterinarian involves inducing vomiting within two hours of ingestion and administration of benzodiazepines or barbiturates for seizures, antiarrhythmics for heart arrhythmias, and fluid diuresis. Theobromine is also suspected to induce right atrial cardiomyopathy other long term exposure at levels equivalent to ~15 g of dark chocolate per kg of weight and per day.

A typical 20 kg (44 lb) dog will normally experience intestinal distress after eating less than 240 g (8.5 oz) of dark chocolate, but won't necessarily experience bradycardia or tachyarrhythmia unless it eats at least 0.5 kg (1.1 lb) of milk chocolate. According to the Merck Veterinary Manual, baker's chocolate of approximately 1.3 g/kg (0.02 oz/lb) of a dog's body weight is sufficient to cause symptoms of toxicity. For example, a typical 25-gram (0.88 oz) baker's chocolate bar would be enough to produce symptoms in a 20-kilogram (44 lb) dog. Large breeds (> 100 pounds / 45 kilograms) can safely consume chocolate in limited quantities, but care must still be taken, as they can safely eat only about a quarter the amount a human can, and should not be intentionally fed it; peanut butter is often recommended as a safer alternative.