| abstract |
New sydnonimine deriv. of formula (I): (where R1=R2=CH3; R4 = benzoyl, o- or p-chlorobenzoyl, o-methylbenzoyl, cylohexylcarbonyl, cyclopropylcarbonyl, nicotinoyl or t-butylacetyl; or R1=R2 = morpholino, R4 = cyclohexylcarbonyl; or R1 = CH3, R2 = piperonyl, R4 = H, HX = acid e.g. HCl) are prepared by the acid catalysed cyclisation of N-nitrosoaminoacetonitrile, or by reacting: (R1R2)N-NH-CH2-C(=NH).-OR6.HX with NOCl. |