Organic Chemistry of Explosives

Addition and condensation reactions 43

1.10.3 Mannich reaction

R 2 NCH 2 + H 2 O (Eq. 1.4)

R 2 NCH 2 C(NO 2 ) 3 (Eq. 1.5)

R 2 NCH 2 OH

R 2 NCH 2

R 2 NH + CH 2 O

+ C(NO 2 ) 3

Figure 1.73

The Mannich reaction is an excellent route to polynitroaliphatic amines and their deriva-

tives.β-Nitroalkylamines are formed from the reaction of an amine and aldehyde in the

presence of a nitroalkane (Equations 1.4 and 1.5).^282 −^296 A large number of these reactions

use nitroform,^285 −^287 fluorodinitromethane,^37 ,^256 ,^261 ,^262 or their methylol derivatives, 2,2,2-

trinitroethanol^284 ,^291 and 2-fluoro-2,2-dinitroethanol,^37 ,^256 ,^261 ,^262 to synthesize the correspond-

ing trinitromethyl and fluorodinitromethyl derivatives respectively.

Primary and secondary nitroalkanes, dinitromethane,^282 and terminalgem-dinitroaliphatic

compounds like 1,1-dinitroethane,^284 ,^288 all contain acidic protons and have been used to

generate Mannich products. Formaldehyde is commonly used in these reactions although the

use of other aliphatic aldehydes has been reported.^282 The nitroalkane component is frequently

generatedin situfrom its methylol derivative, a reaction which also generates formaldehyde.

Ammonia,^282 ,^289 −^291 aliphatic amines,^282 −^289 hydrazine,^288 ,^289 and even urea^291 have been used

as the amine component of Mannich reactions.

C

O

H 2 N NH 2

NO 2

C

NO 2

2 N CH 2 OHO

NO 2

2 NCHCO 2 NHCONHCH 2

NO 2

CNO 2

NO 2

NO 2

159

+

82 %

160

(DiTeU)

Figure 1.74

HC(NO 2 ) 3 HN

CH 2 C(NO 2 ) 3

or (CH 2 ) 6 N 4 , 60 –70 % CH 2 C(NO 2 ) 3

NH 3 , CH 2 O, 90 %

161

112

Figure 1.75

The powerful explosive, bis(2,2,2-trinitroethyl)urea (160) (DiTeU), is synthesized from the

reaction of 2,2,2-trinitroethanol (159) with urea, or from the direct reaction of nitroform with

formaldehyde and urea.^291 Bis(2,2,2-trinitroethyl)amine (161) has been synthesized from the

reaction of 2,2,2-trinitroethanol with ammonia and also from the reaction of nitroform (112)

with formaldehyde and ammonia, or hexamine.^291 ,^296

NH 2 NH 2

AcOH (aq)

NO 2

C

NO 2

3 CH 2 OHCH

NO 2

C

NO 2

CH 3 CH 2 NHNHCH 2 C

NO 2

NO 2

CH 3

60 °C, 73 %

+

25 162

Figure 1.76