Organic Chemistry of Explosives

Addition and condensation reactions 37

+2 H 2 C CHY

MeOH, NaOH

C

NO 2

NO 2

(CH 2 )n C

NO 2

NO 2

NO 2

NO 2

YCH 2 CH 2 (CH 2 )n

Y = COR, CO 2 R, CONH 2 ,

CN, CHO, SO 2 R etc.

131, X = H

132, X = CH 2 OH

CC

NO 2

CH 2 CH 2 Y

NO 2

133

XX

Figure 1.59

Many of the Michael reactions involving the addition of polynitroaliphatic compounds to

Michael acceptors use the corresponding methylol derivatives, which are deformylated in the

presence of base to give the nitronate anion and formaldehyde. Such procedures are primarily

for safety reasons because the nitronate salts of many polynitroaliphatic compounds are shock

sensitive explosives. Feuer and co-workers^250 investigated the Michael reactions of numerous

α,β-unsaturated compounds withα,α,ω,ω-tetranitroalkanes (131) and their bis-methylol (132)

derivatives. Interest in the Michael adducts derived fromα,α,ω,ω-tetranitroalkanes (133) partly

stems from their potential use for the synthesis of energetic oligomers;^250 simple functional

group conversion of the terminal appendages giving rise to alcohol, carboxylic acid, isocyanate

functionality etc.

SOCl 2

C

NO 2

NO 2

HO 2 C(CH 2 ) 2 (CH 2 ) 2 C

NO 2

NO 2

(CH 2 ) 2 CO 2 H

NO 2

NO 2

C(CH 2 ) 2 (CH 2 ) 2

O

Cl

(CH 2 ) 2 C

NO 2

NO 2 O

Cl

C

NO 2

NO 2

H 2 N(CH 2 ) 2 (CH 2 ) 2 C

NO 2

NO 2

(CH 2 ) 2 NH 2 C

NO 2

NO 2

OCN(CH 2 ) 2 (CH 2 ) 2 C

NO 2

NO 2

(CH 2 ) 2 NCO

91 %

1. NaN 3 , 87 %


2. CHCl 3 , 55 °C,
   92 %


3. MeOH, CHCl 3 ,
   55 °C, 83 %


4. HCl (aq), 79 %


5. NaOH (aq)

CC

Figure 1.60

The Michael adducts of fluorodinitromethane have attracted interest as energetic plastisizers

in both propellant and explosive formulations. Such adducts are usually synthesized by mixing

the Michael acceptor with fluorodinitromethane or 2-fluoro-2,2-dinitroethanol in the presence

of base.^256 ,^261 ,^262 ,^266 In much the same way, 2,2,2-trinitroethanol can be used as a source of

nitroform, and both 2,2-dinitroethanol and 2,2-dinitro-1,3-propanediol used as a source of

dinitromethane.

H 2 C CHX

H 2 O, OH

FCH(NO 2 ) 2

NO 2

C

NO 2

F

X = COCH 3 , 72%

X = CO 2 Et, 56 %

X = CN, 28 %

+ CH 2 CH 2 X

Figure 1.61

The observant may ask, ‘Why does the alkoxide anion of the nitroalcohol not add to the

Michael acceptor?’ The addition of alkoxide anions to Michael acceptors is well known, but