Chloracylierung und Bromacylierung von Carbonylverbindungen: Eine in Vergessenheit geratene Carbonylreaktion. I. Präparative Anwendungsbreite

Chloroacylation and bromoacylation of carbonyl compounds: A forgotten carbonyl reaction. I. Scope of the reaction Aliphatic, α,β-unsaturated and aromatic aldehydes as well as aliphatic ketones react with acyl halides to (α-haloalkyl)esters. These bifunctional derivates contain two leaving groups of different reactivity. The scope of this scarcely of this scarcely known carbonyl reaction is discussed.     

121Sb-Mössbauer-Spektren von Antimon(V)-Verbindungen. II

¹²¹Sb Mössbauer Spectra of Antimony (V) Compounds. II The Mössbauer resonance effect of ¹²¹Sb has been studied at 4.2 K in a series of 11 antimony(V) compounds which are in most cases bridged. Isomer shift and quadrupole splitting variations are considered in the light of results of X-ray and vibrational spectroscopy. Preparation and the vibrational spectra of [NMe₄][SbCl₄(n₃)₂] are described. Within the limitations of available structural data related tin compounds are compared with those of corresponding ¹¹⁹Sn Mössbauer spectra.     

Opening of a 1,3-dioxolane by nucleophilic attack at a ketal methylene

A novel type of opening of an ethylene ketal has been observed in the reaction of 1 with alane RA1Me₂. The reaction is explained in terms of a nucleophilic attack on the ketal methylene synchronous with participation by one of the ketal oxygens in the opening of the epoxide function located across the 7-membered ring of 1.     

1,3-Cycloaddition von alkinen an hetero-1,3-diene 1-aminopyrrole aus 1,2-diazabuta-1,3-dienen und 1-diethylaminopropin

1-Aminopyrroles (4) are obtained by reaction of 1,2-diazabuta-1,3-dienes (1) and ynamines (2). This reaction represents one of the very rare examples of 1,3-cycloaddition processes of alkynes and hetero-1,3-dienes.     

Palladium-promoted Cyclization of Tetra-alkylated 1-Arylazonaphthalenes to 2-Aryl-benzo[g]indazoles

1-Arylazonaphthalenes with all the potential cyclopalladation sites (one peri- and three ortho-positions) substituted by methyl or ethyl groups react with stoicheiometric or catalytic amounts of sodium tetrachloropalladate(II) to the corresponding 2-arylbenzo[g]indazoles. Possible mechanisms for the catalytic cyclization reaction are proposed.