Routes via Electron-deficient Nitrogen Species

Reagents i, azobisisobutyronitrile-CgHia-MeOH, 60 °C ii, AgClO -McjCO iii AlCIg-CHijCla iv, BFs-CHzCla v, excess AlCls-CHjCl,.  

4-Phenyl-l,2,4-triazolinedione reacts with the valence isomer of cyclo-octatetraene in the expected [4 + 2] manner reaction to give (58) probably proceeds via a dipolar intermediate. In support of this view fluoro- and chloro-cyclo-octatetraene do not, but bromo- and iodo-cyclo-octatetraene do give adducts of type (58). Methoxy- and phenoxy-cyclo-octatetraene favour adducts of type (58). 

Miscellaneous Reactions. Enamines of quinuclidone have been elaborated to give ketones of type (63), and enamines of piperidones to give further 3-azabicyclo[3,3,l]nonanes. The bridgehead urea (64) was obtained by the reaction of phosgene with (65), Portoghese has extended the preparation 

We also note here the synthesis of (70) and (71) by condensation of a tetrahydrothiapyran-4-one or a piperidone with benzaldehyde and ammonium acetate, of the sulphonamide (72), and of the products of reaction of phosphonous chlorides with the diamines (73)—(75). The synthesis and X-ray structural analysis of (76) are reported.  

Further synthetic studies have extended the availability of different cryp-tates, which are of considerable interest owing to the possible selectivity of association with different cations. The amine (77) by inversion is capable of atropoisomerization. Monoprotonation or diprotonation leads to salts which can only be deprotonated with great difficulty. This implies that in the ammonium salts the protons must be located inside the cavity. The extraordinary properties of (77) are demonstrated by the recovery of the diammonium salt unchanged after solution in 5N-potassium hydroxide at room temperature for 18 days. Cryptate complexes of various metal salts with (78) show the inclusion of the cation in the cavity, and further cryptates derived from (79) and related compounds are reported.  

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