It is shown that the exclusive 1,4-addition of N-nitromethylphthalimide 4a to unhindered α,β-unsaturated ketones and esters can be effected by non-nucleophilic bases, such as sodium hydride or potassium fluoride, in dimethyl sulfoxide. The phthalimido moiety can be removed from the adducts with hydroxylamine or 1,2-dianilinoethane to give the oximes or diphenylimidazolidines of 1,4-ketoaldehydes. The ethylene ketal 5 of 3-formylcyclohexanone could easily be recovered from the imidazolidine 10, but it was not possible to transform 11 into 3-formylcyclohexanone under similar conditions. It is further shown that reactions, such as the Knoevenagel condensation, or the Paal–Knorr synthesis of pyrroles, can be achieved directly on the adducts without the need for isolating the unstable 4-formyl carbonyl compounds. N-Nitromethylphthalimide thus serves as a new formyl anion equivalent.

The reaction of thiophosgene with α-diazocarbonyl compounds produced mixtures of 1,2,3-and 1,3,4-thiadiazoles, in which the latter predominated, irrespective of whether the bis(α-diazoacyl)mercury derivatives or the free diazo compounds were used. In contrast, ethyl chlorodithioformate gave exclusively 1,3,4-thiadiazoles with α-diazocarbonyl compounds in the presence of triethylamine and only 1,2,3-thiadiazoles when the bis(α-diazoacyl)mercury derivatives were used.

The synthesis of the stable potassium salts of the first known 1,2,3‐thiadiazole‐5‐thiols is described.

Die Titelverbindung (II) reagiert mit ungehinderten ogß‐ungesättigten Ketonen und Estern (III) zu den 1,4‐Addukten (IV) (von (IVb), (IVc) und (IVd) (R1: ‐Me) werden Gemische der threo‐ und erythro‐Isomeren erhalten).

Thiophosgen reagiert mit Diazocarbonyl‐Verbindungen, z.B. (I), zu einem Gemisch aus den Thiadiazolen (II) und (III), indem das letztere bevorzugt gebildet wird, gleichgültig ob die freie Diazoverbindung (I) oder das Hg‐Derivat (IVa) verwendet wird.