Gabriel, Ber., 1891, 4, 7 3; 1896, 29, p. 2610); and by the action of phosphorus pentasulphide on acyl-O-bromalkylamides (A.
Bamberger, Ber., 1893, 26, p. 2786): CsH5N :N N :N jC COC6H5 - C6H5NH2+C6H4K C 6 H5 NH N N:C 0006H5; by the reduction of symmetrical acyl-ortho-nitrophenyl hydrazines (e.g.
From these acyl derivatives the elements of water are removed, either by simple heating or by boiling their aqueous solution; this elimination is accompanied by the formation of the azoxime ring.
Those containing more than one acyl group are formed by the action of carbonyl chloride on acid amides: COC1 2 +2CH 3 Conh 2 = Co(NHCOCH3)2+2HC1.
The orthoand parasemidines can be readily distinguished by their behaviour with different reagents; thus with nitrous acid the ortho-semidines give azimido compounds, whilst the para-semidines give complex diazo derivatives; with formic or acetic acids the ortho-semidines give anhydro compounds of a basic character, the para-semidines give acyl products possessing no basic character.