Struktur und Chemie von tautomeriefähigen Heterocyclen, II. Trimethylsilylierung von Diethylmalonohydrazid und seinen Monomethyl‐Derivaten. NMR‐Spektroskopische Strukturuntersuchung der Produkte

Structure and Chemistry of Heterocycles Capable of Tautomerism, II. Trimethylsilylation of Diethylmalonohydrazide and its Monomethyl Derivatives. NMR Spectroscopic Study of the Structure of the Products The trimethylsilylation of diethylmalonohydrazide ( 2 ) and its monomethyl derivatives 3 and 4 yields silyl compounds which only exist in the lactam‐lactim form. While the trimethylsilylation of 2 with two equivalents of chlorotrimethylsilane and two equivalents of triethylamine gives the N , O ‐disilyl derivative 6 , the use of one equivalent of each affords the O ‐silyl compound 5 in pure state. 5 is also formed in the reaction of 6 with 2 by catalysis with triethylamine. The lactam‐lactim structure of 5 and 6 as well as of the trimethylsilyl derivatives 7 and 8 of the isomeric compounds 3 and 4 , respectively, is established by 1 H, 13 C, and 29 Si NMR spectroscopy.