1.4- Dibromobutane, spectrum

As mentioned already, the INEPT spectra are typified by the antiphase character of the individual multiplets. The INEPT C-NMR spectrum of 1,2-dibromobutane is shown, along with the normal off-resonance C-NMR spectrum, in Fig. 2.12. Doublets show one peak with positive phase and the other with negative phase. Triplets show the outer two peaks with positive and negative amplitudes and the central peak with a weak positive amplitude. Quartets have the first two peaks with positive amplitudes and the remaining two peaks with negative amplitudes. 

The representative experimental procedure is as follows 1,4-dibromobutane (1 mmol, 0.215 g) and sodium azide (2.5 mmol, 0.163 g) in water (2 mL) were placed in a 10 mL crimp-sealed thick-walled glass tube equipped with a pressure sensor and a magnetic stirrer. The reaction tube was placed inside the cavity of a CEM Discover focused microwave synthesis system, operated at 120 + 5°C (temperature monitored by a built-in infrared sensor), power 70-100 Watt and pressure 60-100 psi, for 30 minutes. After completion of the reaction, diethyl ether was added to extract the alkyl azide. GC/MS analysis indicated the disappearance of alkyl halides. FT-IR spectrum of crude product was obtained using a FT-IR spectrometer and the formation of alkyl azide was confirmed by the characteristic IR adsorption around 2100 cm Removal of the solvent under reduced pressure (rotary evaporator) afforded the product, 1,4-diazido-butane (0.125 g) in 89% yield. 

Butane has two different types of protons it will exhibit two signals in its H NMR spectrum. (d) Like butane, 1,4-dibromobutane has two different types of protons. This can be illustrated by using a chlorine atom as a test group. 

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