Soman properties

Chemical warfare agents, such as soman and sarin, sometimes termed nerve gases, are powerful anticholinesterases, which bear some resemblance in structure and properties, to the OP insecticides. A major difference from most insecticides is their high volatility. These agents were possessed by the major powers during World War II, althongh they were never employed in warfare. 

The carbamate and OP insecticides and the organophosphorous nerve gases soman, sarin, and tabun all act as anticholinesterases, and most of their toxicity is attributed to this property. The naturally occurring carbamate physostigmine, which has been used in medicine, is also an anticholinesterase. Some OP compounds can cause relatively long-lasting inhibition of the enzyme because of the phenomenon of... 

A positive property of the most active reactivators of the second generation lies in their ability to reduce 2 to 2.5 times aging rate of AChE inhibited with soman. 

Ray R, Clark III OE, Ford KW, Knight KR, Harris LW, Broomfield CA. A novel tertiary pyridostigmine derivative [3-(N,N-Dimethylcarbamyloxy)-l-methyl-A3-tetrahydropyridine] anticholinesterase properties and efficacy against soman. Fundam. Appl. Toxicol. 16 267-274, 1991. 

Lundy, P.M., and Tremblay, K.P. Ganglion blocking properties of some blspyridlnium soman antagonists. Eur. J. Pharmacol. 60 47-53, 1979. 

Irreversible cholinesterases are mostly organophosphorus compounds and combine only with esteratic site of cholinesterase and that site gets phosphorylated. The hydrolysis of phosphorylated site produces irreversible inhibition of cholinesterase. And, because, of this property, the therapeutic usefulness is very limited. Most of the compounds are used as insecticides e.g. parathion, malathion and war gases e.g. tabun, sarin, soman etc. 

Loke WK, Simm MK, Go ML -substituted derivatives of pralidoxime Muscarinic properties and protection against soman effects in rats. Eur J Pharmacol 2002 442 279. [PMID 12065082]... 

Kaczmarek A, Gorb L, Sadlej AJ, Leszczynski J (2004) Sarin and Soman Structure and Properties, Struct Chem 15 517-525... 

Benschop, H.P., Konings, C.A.G., Van Genderen, J., De Jong, L.P.A. (1984). Isolation, anticholinesterase properties and acute toxicity in mice of the four stereoisomers of soman. Toxicol. Appl. Pharmacol. 90 61. 

Wang, Q.D., Sun, M.J., Zhang, H., Huang, C.F. (1998). Purification and properties of soman-hydrolyzing enzyme from human liver. J. Biochem. Mol. Toxicol. 12 213-7. 

An important reason for calculating the electrostatic potential distribution is to obtain experimentally measurable properties. In some cases the electrostatic potential or field itself is directly measurable. In these cases no further calculation is necessary to obtain the appropriate experimental quantity. Examples of applications like this include the measurement and calculation of a-helix potentials and fields (Lockhart and Kim 1993 Lockhart and Kim 1992 Sitkoff et al. 1994a), the measurment and calculation of potentials around DNA (Hecht and Honig 1995 Shin and Hubbell 1992) and at membrane surfaces (McDaniel et al. 1986). Another application is when the stabilization potential at a particular site in a protein is required. An example is the evaluation of the protein potential at the oxyanion hole in a serine protease (Soman et al. 1989). Most experimental parameters of interest, however, are obtained by combining the results of an electrostatic calculation with further theoretical analysis or calculations. 

Chettur, G., J.J. DeFrank, B.J. Gallo, F.C.G. Hoskin, S. Mainer, F.M. Robbins, K.E. Steinmann, and J.E. Walker. 1988. Soman-hydrolyzing and -detoxifying properties of an enzyme from a therophilic bacterium. Fundam. Appl. Toxicol. 11 373-380. 

Physical Properties. Pure soman is a colorless liquid with a somewhat fruity odor. It has density 1.01 g/mL (20°C), vapor pressure of 0.27 mm/Hg (20°C), mp of —80°C, and bp of 190°C (85°C at 15 mm/Hg). Distillation is accompanied by decomposition that begins near 130°C. Soman s solubility in water is about 20% at 25°C. It is only about 20% as soluble in water as is tabun. With two different chiral centers, it exists as four stereoisomers (Benschop et al., 1985), each with a different toxicity. The lethal concentration (inhalation) in humans is estimated at approximately 25-50 mg min/m (Somani et al., 1992). 

---