Determination of mass spectral and fragmentation pattern of some centrally-acting 1,3-cyclohexandione derivatives

Abstract

Many of the drugs currently used in clinical practice possess undesirable side effects, which make some patients less inclined to comply with recommended dosage regimen. Also, therapeutic failure has resulted from development of resistance by organisms to some drugs including antimalarials and antibiotics. There is need therefore, to find safer and effective alternatives devoid of the problems stated earlier. The cyclohexanediones are quite reactive and various workers have obtained several derivatives, which have been found to be biologically active with some possessing useful antimicrobial and herbicidal activities. The 1, 3-cyclohexanedion carboxylate and nine aryl- and arylalkylamino derivatives: ethyl 4-hydroxy-6-methyl-2-oxo-3-cyclohexene-1-carboxylate: ethyl 6-methyl-2-oxo-4-phenylamino-3-cyclohexene-1-carboxylate; ethyl 4-benzylamino 6-methyl-2-oxo-3-cyclohexene-1-carboxylate; ethyl 6-methyl-2-oxo-4-(2'-phenylethylamino)-3-cyclohexene-1-carboxylate; 6-methyl-2-oxo-4-phenylamino-3-cyclohexene-1-(N-phenyl)-carboxamide; 6-methyl-2-oxo-4-phenylamino-3-cyclohexene-1-(N-benzyl)-carboxamide; 4-benzylamino-6-methyl-2-oxo-3-cyclohexene-1-(N-benzyl) carboxamide; 4-benzylamino-6-methyl-2-oxo-3-cyclohexene-1-(N-2'-phenylethyl)-carboxamide; and 6-methyl-2-oxo-4-(2'-phenylethylamino)-3-cyclohexene-1-(N-benzyl)-carboxamide were synthesized. Phenyl, benzyl, phenylethyl, and their amino and carboxy derivatives fragment ions observed in the mass spectra of the corresponding compounds. Most of the compounds except those with phenylamino substituent at the 4-C caused reduction in activity of and sedation in chicks, indicating that they possessed central nervous system depressant properties. Thus they could be useful in the treatment of mental agitations and as muscle relaxants

Key words: Cyclohexanediones; Mass spectra; Fragmentation pattern; C.N.S. depressant.

Nig. J. Pharm. Res. 3(1) 2004: 72-81