Eric Cuthbertson

Tellurium extrusion: a novel method for carbon–carbon bond formation

Pyrolysis of 9-tellurabicyclo[3,3,1]nona-2,6-diene (II) in [2H8]toluene at 175° leads to loss of elemental tellurium and quantitative formation of bicyclo-[5,1,0]octa-2,5-diene (III) which was also formed independently by the action of Te2– anion on the dibromide (I) during the preparation of (II).

Structure and transformation of products of the reactions of 2,2″-thiodi-isobutyrophenone with hydrazine

The novel course of the reaction of the title dioxo-sulphide (II) with hydrazine is described. In absence of acid none of the expected dihydrothiadiazepine (Ia) could be detected; the major product, a monohydrazone (IV), being accompanied by other products including 2,2,4,4-tetramethyl-1,5-diphenyl-8-oxa-3-thia-6,7-diazabicyclo[3.2.1]octane (III) whose structure was elucidated by spectroscopic and X-ray crystallographic methods: compound (III) crystallises in the triclinic space group P with a= 9·911, b= 15·297, c= 6·257 A, α= 103·02°, β= 106·15°, γ= 81·17°, Z= 2, and the structure was refined to a final R value of 7·7% for 2055 independent reflections. The thiadiazepine (Ia) could, however, be obtained by treatment of a crude reaction mixture in pyridine with strong mineral acid, or by dehydration of (III) with acetic acid. The reaction of (III) with molecular oxygen gives, depending on temperature, either the ozonide (VI) or the epoxide (VII) in good yield.

Flexible two-step synthesis of the bicyclo[3.3.1]nona-2,6-diene skeleton and its 9-hetera-analogues from (Z,Z)-cyclo-octa-1,5-diene

A new method for the preparation of the 9-heterabicyclo[3.3.1]nona-2,6-dienes (Ia and d–f), and of 9,9-dicyanobicyclo[3.3.1]nona-2,6-diene (Ig) from (Z,Z)-cis-3,7-dibromocyclo-octa-1,5-diene (II) is described.

A comparison of 2,7-di­hydro-2,2,7,7-tetra­methyl-3,6-di­phenyl-1,4,5-thiadiazepine and the corresponding 1,1-­dioxide

The structures of the highly substituted title heterocycles, C(20)H(22)N(2)S and C(20)H(22)N(2)O(2)S, have been determined at 123 (1) K. Both molecules possess exact C(2) symmetry and the seven-membered rings have very similar twist-boat conformations. The magnitudes of the C-S-C bond angles, 107.13 (6) and 108.27 (7) degrees, respectively, are influenced significantly by the four substituent methyl groups on the seven-membered rings.

Structure and novel reactivity of a new heterocyclic bridged ring system

Reaction of the diketo-sulphide (I) with anhydrous hydrazine in pyridine leads to the formation of (II), whose hitherto unknown ring system has been structurally elucidated by spectroscopic and X-ray crystallographic methods; (II) is stable in the crystal, but in benzene solution in the presence of oxygen undergoes a remarkable transformation into the ozonide sulphide (III) in effectively quantitative yield.