226 Synthetic Routes toN-Nitro
Millar and co-workers124–126studied the ring-opening nitration of strained nitrogen hetero-
cycles with dinitrogen pentoxide as a route to compounds containing both nitrate ester and
nitramino functionality. The reaction of aziridines (140) and azetidines (142) with dinitrogen
pentoxide in inert solvents causes ring C–N bond cleavage and can be used to form 1,2- (141)
and 1,3- (143) nitramine-nitrates respectively. This is analogous to work in which epoxides
and oxetanes are reacted with dinitrogen pentoxide to form 1,2- and 1,3-dinitrate esters re-
spectively (Section 3.4). Such reactions are chemically very efficient because the whole of the
nitrogen pentoxide molecule is incorporated into the product. The 1,2-nitramine-nitrate system
is present in high explosives such as DINA and pentryl.
5.8.1 Aziridines
Millar and co-workers124–126 studied the reaction of dinitrogen pentoxide in chlorinated
solvents with a number of differentN-substituted aziridines and found that reactions are
highly dependent on the nature of theN-substituent on the aziridine nitrogen (Table 5.9).
N-Alkylaziridines give good yields of 1,2-nitramine-nitrate product (Table 5.9, Entry 1). These
Nn-BuO 2 NONNO
2CH 2 (CH 2 ) 2 CH 3NCO 2 EtO 2 NON
NO 2CO 2 EtO 2 NO ONO 2
ONNO CH 3 NO 2 NO 2 CH 3
CNH 3 CNCH 3
(148)NCH 2 CH 2 OHO 2 N NCH 2 CH 2 ONO 2CH 2 CH 2 ONO 2O 2 NNO 2NO 2 (151)N NNO 2NO 2O 2 N
CH 2 CH 2 ONO 2NO 212a31.0 : 1.01.1 : 1.06982 a
67 b2.2 : 1.0 50 c2b 1.0 : 1.0452.2 : 1.0 < 10d1.13 : 1.0 76(144) (145)(146) (147)(149)(150) (7)(152)Table 5.9
1,2-Nitramine-nitrates from the reaction of aziridines with
dinitrogen pentoxide (ref. 124)a Product contains ~10 % acyl nitrate impurity. b Product contains < 5 % acyl nitrate impurity. c Product is
readily hydrolyzed. d Bulk of the product mass is polymeric material.Mole ratio
Entry Substrate N 2 O 5 : aziridine Product Yield (%)