Nujol

Nujol A trade name for a heavy medicinal liquid paraffin. Extensively used as a mulling agent in spectroscopy. 

Nujol . To measure the CD speetnim, they had to overeome the birefringenee of the strained diamond windows of the high-pressure eell. They did this by reeording and averaging speetra of the sample—and of a... 

Interpretation of spectra. The infrared spectrum of m-hydroxybenzoic acid (solid ground in Nujol) is shown in Fig. A, 7, 1. The more important bands may be interpreted as follows. 

H deformation vibration. It is readily observed in the spectrum as it lies between two characteristic Nujol bands in this region (Table V). 

IR and Raman studies of heterocycles today cover two different fields. For simple and symmetrical molecules very elaborate experiments (argon matrices, isotopic labelling) and complex calculations lead to the complete assignment of the fundamentals, tones and harmonics. However, the description of modes ought to be only approximate, since in a molecule like pyrazole there are no pure ones. This means that it is not correct to write that the band at 878 cm is y(CH), and the only correct assertion is that the y(CH) mode contributes to the band. On the other hand, IR spectroscopy is used as an analytical tool for identifying structures, and in this case, bands are assigned to r-iCO) or 5(NH) on the basis of a simple Nujol mull spectrum and conventional tables. Both atttitudes, almost antagonistic to each other, are discussed in this section. 

A slight positive pressure of argon was maintained in the vessel throughout the reaction by using an argon line connected to both a bubbler containing Nujol and the inlet on the dry ice condenser. 

A-(9-Acridinyl)maleiinide (NAM) [49759-20-8] M 274.3, m 248 , 255-258 . Purified by chromatography on silica gel using CH2CI2 as eluant. Evaporation of pooled fractions that gave the correct NMR spectra gave a solid which was recrystd from Me2CO as pale yellow prisms. IR v (nujol) 1710 (imide) UV (MeOH) (nm), (e M- cm ) 251 (159 500), 343 shoulder (7 700), 360 (12 400) and 382shoulder (47... 

A-Hydroxy-5-norbornene-2,3-dicarboxylic acid imide [21715-90-2] M 179.2, m 165-166", 166-169", pKesi-6 Dissolve in CHCI3, filter, evaporate and recrystallise from EtOAc. IR (nujol) 1695, 1710 and 1770 (C=0), and 3100 (OH) cm. 0-Acetyl derivative has m 113-114° (from EtOH) with IR bands at 1730, 1770 and 1815 cm only, and the 0-benzoyl derivative has m 143-144° (from propan-2-ol or C6H6). [Bauer and Miarka J Org Chem 24 1293 1959 Fujino et al. Chem Pharm Bull Jpn 22 1857 1974],... 

To an ethanolic solution of sodium ethoxide prepared by addition of 0.46 g (0.02 mole) of freshly cut sodium metal in 100 mL of absolute ethanol was slowly added 5.10 g (0.02 mole) of ethyl 4-nitrobenzylthioacetate 28 with stirring at 5°C. The mixture was refluxed for about 4 to 6 hours until the reaction was complete (monitored by tic). The resultant mixture was allowed to cool to room temperature and then added into an ice-water mixture. The solution was neutralized with slow addition of dilute aqueous hydrochloric acid (10%). The precipitated solid was removed by filtration, washed with water, and recrystallized from a dimethylformamide-ethanol (T.l) mixture yielding 2.10 g (76 %) of 29 as a light brown crystalline solid, mp 227°C ir (nujol) (neat (1710 cm ms m/z Til (NT). Anal. Calcd. For C13H11NO4S C, 56.31 H, 3.97 N, 5.05 S, 11.55. Found C, 56.36 H, 3.95 N, 5.01 S, 11.49. 

Mason has determined the infrared spectrum of pyrido[3,2-d]-pyrimidin-4(3ff)-one (149, N in position 5) in chloroform solution and as a KBr disc and has suggested that the low frequency of th e NH band (3389 cm ) and high frequency of the C=0 band (1745 cm i) in the solution spectra are indicative of a quasi o-quinonoid form. The infrared spectra of the four pyridopyrimidin-4(377)-ones (149), the four 2,4(ljff,3//)-diones (150), and a number of substituted derivatives, have been determined, as Nujol mulls, in these laboratories. ... 

Another rather extensive series of similar data, obtained using CS2 solutions and nujol mulls, has been published by Shindo (Fig. 4). His series include considerable data for jS-substituted compounds, for which the question of a choice of substituent constants does not arise. His data also show considerable scatter but seem to suggest strongly that <7+-values are indicated for + M substituents and normal <7-values for —M substituents. The conclusion is confirmed by the short series of similar data reported by Costa and Blasina and by Shupack and Orchin. The data of the latter authors for the NO frequencies in mws-ethylene pyridine N-oxide dichloroplatinum(II) complexes are also moderately well correlated with <7+-values. 

Fig. 4. The N—O stretching frequencies of substituted pyridine 1-oxides (a) in CS2 and (b) in Nujol mull cf. ref. 47. Solid circles if a = a = a crossed circles, a = a+ barred circle, a ( a) open circle, a = a cross, a+ ( ar).

Tautomeric studies of equilibria between enamino and methylene imino form have been reported for several heterocycles. Tautomerism of 1,2,4-tri-azino[4,3- ]quinoxalin-5-ones was deduced to be solvent dependent the enamino form 170b is predominant in DMSO-dg ( H NMR), whereas 170a is the major tautomer in the solid state (IR in nujol) (90JHC691 95H2057) (cf. Section III,B). 

Pyrido[3,4-fe]pyraziii-3- and -2-oiies exist in the enamino forms 171 and 172 respectively in DMSO-dg ( H NMR spectroscopy) and in the solid state (IR spectra in nujol), and temperature appears not to affect these imine-enamine equilibria (97JHC773). 

Non-polar hydrocarbon-type liquid phases, e.g. paraffin oil(Nujol), squalane, Apiezon L grease and silicone-gum rubber the latter is used for high-temperature work (upper limit 400°C). 

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