Isocyanides, reactions

Isocyanide reaction. Since chloral hydrate is readily converted into chloroform by alkali, it will give the isocyanide reaction. To a few crystals of the solid add about 5 ml. of alcoholic NaOH solution and a few drops of aniline, and heat the disagreeable odour of phenyl isocyanide, C H(NC, is rapidly detected. 

Isocyanide reaction. Add a few drops of chloroform to about 0 2 g. of the substance, and then 2 3 ml. of ethanolic NaOH solution. Mix well and warm gently the foul odour of isocyanide (carbylamine) is produced. Immediately the odour of isocyanide is detected, cool the tube and add carefully an excess of cone. HCl the isocyanide is thus hydrolysed to the odourless amine. 

Isocyanide reaction. Heat together gently 0 2 g. of the anilide, 3 ml. of ethanolic NaOH solution and i ml. of chloroform hydrolysis of the anilide occurs, and the odour of the isocyanide can be detected after about i minute s heating. [This test clearly differentiates an anilide of type R CONHC Hj from one of type R CO N(CH3)CeH5.]... 

Isocyanide reaction. Repeat Test i for chloroform (above) using 0 5 g. of iodoform instead of i ml. of chloroform the foul odour of isocyanide is produced as before. 

I. Isocyanide reaction. Repeat Test i for chloroform using i ml. of carbon tetrachloride in place of the chloroform. The odour of isocyanide can be detected only after heating gently for several minutes. 

Some of the artificial musks of commerce are mixtures of two or more of the bodies above described, a fact which is easily demonstrated by fractionally crystallising the specimen, when the fractions will show altered melting-points. The principal adulterant of artificial musk is acetanilide. This can, of course, be easily detected by the phenyl-isocyanide reaction or by dissolving it out with hot water. 

Fe(CO)s is fairly inert to substitution reactions, usually requiring Carius tube reactions or high boiling solvents, both with extended reaction times, to reach, in the case of isocyanides (765), disubstitution. As a testimony to the unreactivity of Fe(CO)5 only three publications have appeared on isocyanide reactions with complexes related to this molecule since 1974. Thus, photolysis of Fe(CO)3 P(OAryl)3 2 in the presence of CNMe gave Fe(CO)2 P(OAryl)3 2(CNMe) (766), substitution reactions on Fe(CO)4MA with CNCH2Ph produced Fe(CO)4 x(CNCH2Ph)JtMA (x = 1 -3)(767), and the reaction of Fe3(CO)l2 with CN(CH2) NC (n = 2,6) produced exclusively the dimer [Fe(CO)4]2CN(CH2) NC (168). 

Our initial foray into the isocyanide reactions was the dis-covery(W.) that the alkyl isocyanides RNC (R = CH3, CMe3 or CgHu) cause fission of the Mo-Mo quadruple bond of M02 (O2 CCH3) i, and K1)Mo2C18 to generate the l8-electron seven coordinate cations [Mo(CNR)7]2+ which were isolated as their BFiTand PF6-salts. 

Vinyl isocyanides. Reaction of the lithium salt of (1) with carbonyl compounds gives vinyl isocyanides in 70-85 % yield ... 

I) Isocyanide Reaction of Primary Amines. Place 1 drop of aniline in one test tube, and 1 drop of n butylamine in another. Add to each 3 or 4 drops of chloroform and 1 ml of alcoholic potash. Use the hood.) Warm it for a few seconds. The isocyanides can be recognized by the odor. Clean the tube with concentrated hydrochloric acid, then with water. Write the equation for the reaction. What is the structure of isocyanide ... 

As, Sb, Bi) donor atoms, and with isocyanides. Reaction with butadiene to give the pale yellow tricarbonyl product (m.p. 19 C) is typical" ... 

Successive insertions into a Li—Si bond are believed to form the basis of a novel dimerization of isocyanides Reaction of a range of isocyanides with phenyldimethylsilyllithium, followed by treatment with trialkylchlorosilane, offered silylated dimers of the isocyanide. 

Thus, a plot of (k pp) versus the gas pressure [M] yields a straight line with intercept ( a[/iv]) > and slope k /(k [hv]k(E)). Since the photoactivation rate, k [hv] is known from the intercept, the slope permits the determination of the ratio kJk(E). An example of such a Stem-Volmer plot is shown in Figure 5.17 for the isomerization of the previously mentioned allyl isocyanide reaction, C3H5NC —C3H5CN, in which k [hv] k pp is plotted. This results in an intercept of 1.0 and a slope of kJk(E). The quantity of interest, k(E), can be extracted if we know the deactivation rate, k. This is generally taken to be equal to the gas kinetic collision rate constant (strong collision assumption), which is typically about 10 cm3/(molec sec). 

The half-pressuFes quoted here for both reactions are for the strong collision calculation as explained in Chapter 7, the methyl isocyanide reaction does not conform exactly to the strong collision properties and the observed values of the half-pressure are actually some 20 Torr higher, see Figure 7.3. 

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