Heating of 3,7 di(tert butyl) 1,5 dimethyl 3,7 diazabicyclo[3.3.1]nonan 9 one with hydro bromic acid gave 1,5 dimethyl 3,7 diazabicyclo[3.3.1]nonan 9 one (1,5 dimethylbispidin 9 one). Condensation of this compound or 1,5 dimethylbispidin 9 ol with dialdehydes afforded new compounds containing two 1,3 diazaadamantane moieties in one molecule, which are connected either directly or through spacers.Key words: bispidines condensation, 1,5 dimethyl 3,7 diazabicyclo[3.3.1]nonan 9 one, 1,5 dimethylbispidin 9 one, dialdehydes, bi(1,3 diazaadamantan 6 one).It is known that bispidines possess pronounced biolog ical activity 1-4 and, besides, are of practical interest as complexation agents with metal salts. 5-8 Earlier, 9 we used the condensation of 1,3,5 tri(tert butyl) 1,3,5 triaza cyclohexane with diethyl ketone to obtain 3,7 di(tert butyl) 1,5 dimethyl 3,7 diazabicyclo[3.3.1]nonan 9 one (N,N´ di(tert butyl) 1,5 dimethylbispidin 9 one, 1) in 72% yield. The choice of the tert butyl group as a substitu ent at the nitrogen atoms is explained by a possibility of its further removal. 10 In the present work, we report the synthesis of 1,5 di methyl 3,7 diazabicyclo[3.3.1]nonan 9 one (2a) 11 by heating of bispidinone 1 with hydrobromic acid for 30 min and subsequent alkalization of the reaction mix ture (Scheme 1). The yield of the reaction product 2a was 54%.aaa 1,5 Dimethylbispidinone 2a was reduced with sodium boronhydride to 1,5 dimethyl 3,7 diazabicyclo[3.3.1] nonan 9 ol (1,5 dimethylbispidin 9 ol, 2b) 12 in 68% yield (see Scheme 1).Literature data show that the reaction of bispidines with carbonyl compounds can be used in the synthesis of 1,3 diazaadamantane derivatives. 13 A possibility of such condensation is provided by the closeness of the NH groups in the chair chair conformation of bispidine. In the case of 1,5 disubstituted bispidines, the absence of steric hin drance and the high reactivity of the NH groups make it possible to use a wide range of carbonyl compounds in this condensation. Thus, a series of 2,2 disubstituted 5,7 dis ubstituted 1,3 diazaadamantanes were obtained by the re action of 1,5 disubstituted bispidines with various aliphatic and aromatic aldehydes or aliphatic ketones. 10,14-16In the last years, in organic chemistry an interest is growing to the preparation of enlarged molecules with new or improved properties via their synthesis from bi and polyfunctional molecules. 3,17, 18 We for the first time synthesized the systems 3-6 with low molecular weights containing two 1,3 diazaadamantane fragments with high yields (Scheme 2).We found that such products are formed by the con densation of 1,5 dimethyl substituted bispidines 2a,b with various dialdehydes upon reflux in isopropyl alcohol.
Scheme 1i. 1) HBr, 2) NaOH; ii. NaBH 4 , EtOH.
