Abstract: A method for the preparation of a thiazine derivative, having insecticidal properties, of the formula ##STR1## where each R is hydrogen or an appropriate aromatic or aliphatic substituent and X is hydrogen, halogen or lower alkyl, the method comprising reacting together a sulphur donor, a compound of the formula Y.sub.2 C.dbd.CXNO.sub.2 where Y is halogen (preferably chlorine) or another appropriate leaving group and a compound of the formulaH.sub.2 NCR.sub.2 CR.sub.2 CR.sub.2 OSO.sub.3 H.

Abstract: A method of preparing a thiazolidine derivative of the formula ##STR1## where R, R.sub.1, R.sub.2 R.sub.3 and R.sub.4 are each independently hydrogen or appropriate aromatic or aliphatic substituents, comprises reacting together a sulphur donor, such as sulphur or hydrogen sulphide, an aldehyde of the formula RCHO, such as benzaldehyde or formaldehyde, and an ethanolamine derivative of the formula, or including the radical, NH.sub.2 CR.sub.1 R.sub.2 CR.sub.3 R.sub.4 X, where X is a leaving group. A suitable derivative may be, for instance, aminoethylsulphate (AES). The thiazolidine derivative may be used, for example, as intermediates in the preparation of other compounds such as cysteamine.