ISSN:
1434-193X
Keywords:
Alkynes
;
Cyclizations
;
Nitrogen heterocycles
;
Chemistry
;
General Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
The synthesis of 1,8-diazacyclotetradeca-4,11-diyne (4) was accomplished by reaction of 1,6-dibromo-3-hexyne (11) with ammonia. Similarly, the preparation of 1-azacyclotetradeca-4,11-diyne (5) was achieved from 1,13-dibromotrideca-3,11-diyne (10) and ammonia. The reaction of α,ω-diamines of linear hydrocarbons of the chain length C4 to C10 with 11 yielded the corresponding bicyclic diynes 23-29. The reaction of 4 with 11 yielded 1,8-diazabicyclo[6.6.6]icosa-4,11,16-triyne (14). Similarly, the reaction of 4 with 1,4-dibromo-2-butyne yielded 1,8-diazabicyclo[6.6.4]octadeca-4,11,16-triyne (31). The molecular structures of 1,8-diisopropyl-1,8-diazacyclotetradeca-4,11-diyne (13a), as well as of 14, 24, 27 and 31 were studied by means of the X-ray technique. It was found that 13a adopts a chair-like conformation (C2h) with an equatorial orientation of the isopropyl groups. In 14, 24, 27, and 31 the 14-membered rings adopt a twist-boat conformation. The distance between the nitrogen atoms varies between 4.662(2) and 5.189(2) Å. In the case of 14, 24 and 27 the nitrogen atoms are pyramidalized and point inside the cage while in 31 the substituents at each nitrogen atom and the nitrogen atoms are situated in one plane.
Additional Material:
2 Ill.
Type of Medium:
Electronic Resource
