Organic Chemistry of Explosives

170 Synthetic Routes to AromaticC-Nitro Compounds

CH 3

NO 2

NO 2

1

O 2 N

CH 3

NO 2

NO 2

130

(DATNT)

O 2 N

H 2 N NH 2

N

N

NNH 2

DMSO, NaOMe

65 %

Figure 4.52

Other aminating agents have been studied in relation to efficiency and regioselectivity.^263

4-Amino-1,2,4-triazole (ATA) and 1,1,1-trimethylhydrazinium iodide (TMHI) are efficient

aminating agents; the latter is synthesized from the reaction ofN,N-dimethylhydrazine with

methyl iodide. Mitchell and co-workers^264 synthesized 3,5-diamino-2,4,6-trinitrotoluene (130)

(DATNT) in 65 % yield by treating TNT (1) with 4-amino-1,2,4-triazole and sodium methoxide

in DMSO. This synthesis is significantly more efficient than previous syntheses^265 of this com-

pound. DATNT is considerably more thermally stable than TNT. Mitchell and co-workers^37

used the same methodology for the synthesis of TATB from TNB and picramide (see Sec-

tion 4.8.4). Mitchell and co-workers^266 also reported the synthesis of DATB by treating TNB

with two equivalents of TMHI. A series of 1-substituted 3,5-dinitrobenzenes were aminated

by VNS in the same work.^266

Hydrogen displacement from unsymmetrical substrates like 1,3-dinitrobenzene can produce

a mixture of products. Reaction of 1,3-dinitrobenzene with hydroxylamine produces a mixture

of 2,4-dinitroaniline and 2,6-dinitroaniline; 1,3-diamino-2,4-dinitrobenzene is formed if two

equivalents of hydroxylamine are employed.^260

The effect which amino functionality has on the thermal and impact sensitivity of polyni-

troarylenes (Section 4.8.1.4) makes amination by VNS a method with much future potential

for energetic materials synthesis. Other carbon, nitrogen, oxygen and sulfur nucleophiles can

displace aromatic hydrogen; examples with 1,3-dinitrobenzene^267 and 1,3,5-trinitrobenzene^268

are extensive.

4.8.3.2 Displacement of alkoxy and aryloxy groups

The displacement of alkoxy and aryloxy groups from polynitroarylenes is generally more

difficult than the displacement of halide from similar substrates. This is a consequence of

alkoxy groups being poorer leaving groups than halide anions. In these reactions the nucleophile

should be a poorer leaving group or a better nucleophile than the one being displaced in order

to drive the equilibrium towards the product.

NO 2

7

O 2 N NO 2

OMe

MeO

NO 2

NO 2

131

O 2 N

OEt

O 2 N NO 2

NO 2

8

EtO MeO

OEt

Figure 4.53

2,4,6-Trinitrophenetole (8) can be prepared by heating 2,4,6-trinitroanisole (7) in ethanol

containing a catalytic amount of sodium ethoxide.^269 This reaction is so facile that methanol