Isopropyl isocyanide

Isophthalic acid, 2-hydroxy-, 40,48 Isoprene, addition to dichlorophenyl-phosphine, 43, 73 Isopropyl isocyanide, 41,14 5 Isopropyl-1,2,3,4,5-pen tachlorocyclo-pentadiene, 43, 92... 

The present procedure is the best way of preparing aliphatic isocyanides boiling above ethyl isocyanide. It has been applied to the synthesis of the following isocyanides 6 isopropyl (38%), -butyl (61%), te -butyl (68%), and benzyl (56%). In preparing isopropyl isocyanide or teri-butyl isocyanide, the petroleum ether should be of boiling point 30-35°, as otherwise it is difficult to separate these low-boiling isocyanides in the indicated yield, and,... 

In concentrated sulfuric acid, aromatic polyisocyanides are subject to sulfona-tion. Poly(isopropyl isocyanide) is dissolved in 97%H2S04, and is reprecipitated by the addition of water. Infrared spectra show that some structural change, e.g. hydrolysis, has taken place (26). Poly(sec-butyl isocyanide) is dissolved by the acidic hexafluoroisopropanol with some attendant browning of the solution (7). In spite of the theoretical complexities of polyelectrolytic character introduced into the solution characterization of polyisocyanides in strongly acidic media, such media at least allow viscometric indexing of the various samples of the otherwise insoluble polyisocyanides. 

Fig. 9. Time dependence of the relative viscosity of 1 g/dl of poly(isopropyl isocyanide in dichloroacetic acid at 30° C A original sample, B repeat determination after recycling the...

Polyfsec-butyl isocyanide) has also been examined viscometrically in the manner of poly(isopropyl isocyanide) (8,20). Extrapolation of the data in two stages—first as a function of time—leads to the results shown in Fig. 10. 

Fig. 31. A comparison of the 1H chemical shifts for the E11 valine 72-CH3 protons of the various isonitrile complexes of isolated a chains (o) and p chains (A) of Hb A, the o ( ) and p ( ) chains as identified within an intact Hb A molecule, and sperm whale myoglobin ( ). Ligands CO, carbon monoxide M, methyl isocyanide E, ethyl isocyanide P, n-propyl isocyanide B, n-butyl isocyanide iP, isopropyl isocyanide and tB, tert-butyl isocyanide. [From Mims et al. (1983a)].

Fig. 32. Effects of alkyl isocyanides (a-series) on the 600-MHz ring-current-shifted proton resonances of isolated a chains and (3 chains of Hb A, Hb A, and sperm whale myoglobin (Mb) in 0.2 M phosphate in D20 at pH 6.6 and 21°C MNC, methyl isocyanide ENC, ethyl isocyanide iPNC, isopropyl isocyanide and tBNC, tert-butyl isocyanide. [Adapted from Mims et al. (1983a)].

Figure 14. Models of the (a) syndio conformation and (b) 4/1-helical conformation of poly(isopropyl isocyanide) (56). (Reprinted with permission from ref 181. Copyright 1997 American Chemical Society.)...

The combination of alkyl isoeyanides with ferro-hemoglohin. The equilibria between reduced ferro-hemoglobin and ethyl isocyanide, isopropyl isocyanide, and tertiary butyl isoeyanide were studied spectro-photometrically at 25° C and pH 6.8. The ferrohemo-globin isoeyanides have absorption spectra similar to the spectrum of carbonmonoxyhemoglobin, as shown in Table 2. Concentrations of free ferrohemoglobin... 

On this interpretation the differences in combination constants of the different isocyanides require that the energy of the sterio-hindrance effect be 0.7 kcal mole per heme-isocyanide complex greater for isopropyl isocyanide than for ethyl isocyanide, and be 3.1 kcal mole-1 greater for tertiary butyl isocyanide than for ethyl isocyanide. 

Experimental method. The isocyanides were prepared from the alkylhalides by the silver cyanide method ethyl isocyanide and isopropyl isocyanide according to the directions of Gautier (29), and tertiary butyl isocyanide according to a modified method (30). The physical properties of the preparations used are as follows ethyl isocyanide, bp, 77 -78 C at 750 mm isopropyl isocyanide, bp, 86.5 -87 C at 750 mm tertiary butyl isocyanide, bp, 91°-91.5 C at 750 mm, mp, 8 -10 C, density 0.72. 

The cells used in obtaining the data shown in Fig. 2 had been stored one week. It was found in a set of check experiments reported in Table 3 that the affinity of hemoglobin for isopropyl isocyanide and for tertiary butyl isocyanide does not depend appreciably on whether the cells from which the hemoglobin was prepared had been stored for one day or one week. 

Ethyl and isopropyl isocyanide were added in aqueous solution, and tertiary butyl isocyanide was added directly from a microburette. The hemoglobin was then reduced with dithionite solution. Because of the low solubility of tertiary butyl isocyanide it was not possible to build up a high enough concentration... 

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