Addition and condensation reactions 41form the 1,1-dinitroethane anion (149) (Pathway 1). More unusual is the second reaction
where the base abstracts a hydrogen from 1,1,1-trinitroethane (33), followed by formal elimi-
nation of nitrous acid and the formation of the reactive intermediate, 1,1-dinitroethene (150),
which can react further with any nucleophiles present in a Michael 1,4-addition reaction
(Pathway 2).
Pathway 2CCNO 2NO 2NO 2HHHB:+ B:H + NO 2NO 2NO 2HHB:33150151BCH 2 CNO 2NO 2Figure 1.69Reactions are very dependent on the nature of the base and the reaction conditions
used, for example, reaction of 1,1,1-trinitroethane with aqueous potassium hydroxide, or
hydroxylamine in methanolic potassium methoxide, gives high yields of potassium 1,1-
dinitroethane.^280 However, reaction of 1,1,1-trinitroethane with potassium ethoxide, potas-
sium methoxide and ethanolic potassium cyanide is reported to give 2,2-dinitroethylether,
methyl-2,2-dinitroethylether and 3,3-dinitropropionitrile respectively, all in approximately
80 % yield via the 1,4-addition of ethoxide, methoxide and cyanide anion to 1,1-dinitroethene
respectively.^280
CH 3 C(NO 2 ) 3NO 2NO 2HHCH 2 (CO 2 Et) 2
+
KNO 2(EtO 2 C) 2 CHCH 2 C(NO 2 ) 2 KK CH(CO 2 Et) 2K CH(CO 2 Et) 2
36 %150+ +
33153152Figure 1.70Other bases found to react with 1,1,1-trinitroethane via formation of 1,1-dinitroethene
include: trimethylamine, guanidine and diethylmalonate anion (152), the latter forming (153)
in 36 % yield. Shechter and Zeldin^280 found no correlation as to why some bases react with
1,1,1-trinitroethane so differently to others but noted that simple alkoxides, aliphatic amines,
guanidine, cyanide and malonate anions reacted via the 1,1-dinitroethene pathway.
Frankel^281 discovered a similar reaction to the base-induced formation of 1,1-dinitroethene
from 1,1,1-trinitroethane; treatment of 2-bromo-2,2-dinitroethyl acetate (154) with potassium