Systems containing One Nitrogen Atom

Systems containing One Nitrogen Atom Azetidines and Azetines. - A new synthesis of azetidine, allowing its preparation on a large scale, has been described. The new method involves the addition of sodium azide to acrolein and reduction of the addition product to... 

Reports of bicyclic systems with one nitrogen atom containing two additional heteroatoms in each ring are scant in the literature. Fourteen such ring systems have been reported previously 1-14 <1996CHEC-II(8)733>. The literature examples available during the last decade include 1,2,4-triazino[3,4-Z ][ l,3,4]thiadiazine-4,7-dione 15, [l,2,4]tri-azino[3,4-/d [ 1,3,4]thiadiazinc 16, l,9a-dihydro-8//-l, 2,4-triazino-[3,4-Z ] [1,3,4] thiadiazine-4-oncs 17, [l,3,5]tria-... 

Alkaloids containing one nitrogen atom are known by miscellaneous names for lack of a unified system of nomenclature. 

Buxazidine-B (145), also isolated from B. sempervirens, possesses a primary alcohol group and a keto-group. It has been assigned structure (145) on the basis of i.r. and mass spectra, as well as certain chemical reactions which are not described. This structure, if it is correct, would be particularly interesting as it corresponds to a I6-oxo-dihydrocyclomicrophylline which, in alkaline medium, easily gives (146), containing one nitrogen atom and the 17-en-16-one system. 

Systems containing Two Nitrogen Atoms or One Nitrogen Atom and a Second Heteroatom... 

This chapter reviews bicyclic 6-6 ring systems containing one bridgehead nitrogen atom and one extra heteroatom,... 

Of the possible 10 bicyclic systems containing one bridgehead nitrogen and two extra nitrogen atoms, 1 1 in each ring, nine are known. One new system, pyrimido[l,6-A]pyridazine (system 1 in Table 1), has been reported since CHEC-II(1996) <1996CHEC-II(8)633>. The number of known tricyclic benzo-fused systems is 16. 

Systems of this type are still dominated by those containing a nitrogen atom, particularly with one or more rings fused to the seven-membered ring. The following material is divided into non-fused and fused examples. 

---