Barbiturates Chemical formulae

Figure 7.1 Phenobarbital is a barbiturate with the chemical formula...

Therapeutic Function Sedative, Hypnotic Chemical Name Barbituric acid, 5,5-diallyl-Common Name Diallylbarbituric acid, Allobarbital, Diallymal Structural Formula ... 

When it comes to physicochemical (biological) properties the common structural formulae obscure rather than explain the problem. One of the most convincing examples may be the anaesthetic activity of chemicals. Among general anaesthetics one can identify such diverse chemical families like hydrocarbons, alcohols, ethers, barbiturates, nitrous oxide, steroids, etc. Each one must have anaesthetic activity encoded in its structure but how is it discovered using conventional chemical symbolic The planar or three-dimensional chemical notation can be an obstacle to making a breakthrough in chemistry. 

The names and formulae of some of the psycholeptic compounds which cannot be classified in the major chemical categories so far considered are set out in Table 5.3. Meprobamate VIII) was one of the earliest used tranquillizers. It was developed from mephenesin VII), which was introduced as a muscle relaxant and was soon seen to have a sedative action too. In small doses, meprobamate is a sedative. In larger doses, it causes muscle relaxation and has been classed, with similar compounds, as a tranquillo-sedative . Like the barbiturates, it produces no sign of extrapyramidal or central autonomic stimulation. Well-authenticated reports of addiction to meprobamate have appeared . Both mephenesin and meprobamate produce muscle relaxation by inhibiting interneurones—and hence polysynaptic reflexes—in the spinal cord. Though not described as a hypnotic, meprobamate has been successfully used in the treatment of insomnia, perhaps because it reduces tension. 

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