The invention comprises compounds of the general formula <;FORM:0825514/IV (b)/1>; wherein n is a whole number from 1-6 inclusive, R is hydrogen, cyanoalkyl, alkoxyalkyl, phenyl, nitrophenyl, aminophenyl, hydroxyphenyl, halophenyl, alkoxyphenyl, hydroxynaphthyl, alkoxythiocarbohydrazo, C-pyridyl, C-furyl or carbamoyl when m is 1 and R is alkylene when m is 2 and the preparation thereof (except those compounds in which R represents alkoxythiocarbohydrazo) by reacting a lactam of the general formula <;FORM:0825514/IV (b)/2>; wherein Q is an alkyl radical, with an acyl hydrazide of the general formula (H2N.NH.CO)mR and cyclizing the product obtained by the elimination of water; or (when R represents an alkoxythiocarbohydrazo radical) by reacting a lactim of the above formula with a compound of the general formula H2N.NH.CS.NH.NH.CS.OR1 wherein R1 is an alkyl radical, and cyclizing the product so obtained by the elimination of water. Thiocarbohydrazide - 1 - monothiocarboxylic acid ethyl ester is prepared from thiocarbohydrazide and sodium xanthoacetate. Capryllactim-O-methyl ether is prepared by Beckmann rearrangement of cyclo-octanone oxime to capryllactam and methylating the latter. Specification 340,237, [Group IV], is referred to.;FORM:0825514/IV>;FORM:0825514/IV>