Organic Chemistry of Explosives

Halide displacement 7

treatment of the resultingβ-nitroalkyl bromide with triethylamine, is also a general route to

α-nitroalkenes.^57

The reaction of alkenes with nitronium salts proceeds through a nitrocarbocation. The

product(s) obtained depends on both the nature of the starting alkene and the conditions

used.^3 ,^58

α-Nitroketones have been synthesized from the reactions of silyl enol ethers with nitronium

tetrafluoroborate^59 and tetranitromethane in alkaline media.^60 The reaction of enol acetates with

trifluoroacetyl nitrate, generatedin situfrom ammonium nitrate and trifluoroacetic anhydride,

also yieldsα-nitroketones.^61

1.5 Halide displacement

1.5.1 Victor Meyer reaction

One of the most important reactions for the laboratory synthesis of primary aliphatic nitro

compounds was discovered by V. Meyer and O. St ̈uber^62 in 1872 and involves treating alkyl

halides with a suspension of silver nitrite in anhydrous diethyl ether. Benzene, hexane and

petroleum ether have also been used as solvents for these reactions which are usually conducted

between 0◦C and room temperature in the absence of light.

Primary alkyl iodides and bromides are excellent substrates for the Victor Meyer reaction,

providing a route to both substituted and unsubstituted nitroalkanes (Table 1.1).^63 ,^65 ,^70 ,^71 The

formation of the corresponding nitrite ester is a side-reaction and so the nitroalkane is usually

isolated by distillation when possible. The reaction of primary alkyl chlorides with silver nitrite

is too slow to be synthetically useful. Secondary alkyl halides and substrates with branching on

R X AgNO 2 R NO 2 AgX

Et 2 O

CH 3 CH 2 CH 2 Br

HOCH 2 CH 2 I

H 2 C=CHCH 2 Br

ICH 2 CO 2 Et

(CH 3 ) 2 CHBr

CH 3 CH 2 CH 2 CH 2 Br

CH 3 CH 2 CHBrCH 3

++

X = I or Br

p-O 2 NC 6 H 4 CH 2 Br

p-MeOC 6 H 4 CH 2 Br

67

73

62

55

75

26

77

19–26

19–24

19

13

---

---

5

55

---

24–34

27–37

Alkyl halide Yield (%) of

nitroalkane

Yield (%) of

nitrite ester

Table 1.1

Synthesis of nitroalkanes and their derivatives from the reaction of alkyl

halides with silver nitrite under the Victor Meyer conditions

63

64

65

64

66

67

68

69

69

Ref.