Hydrogen cyanide Formamide

Ritter Reaction (Method 4). A small but important class of amines are manufactured by the Ritter reaction. These are the amines in which the nitrogen atom is adjacent to a tertiary alkyl group. In the Ritter reaction a substituted olefin such as isobutylene reacts with hydrogen cyanide under acidic conditions (12). The resulting formamide is then hydroly2ed to the parent primary amine. Typically sulfuric acid is used in this transformation of an olefin to an amine. Stoichiometric quantities of sulfate salts are produced along with the desired amine. 

Hydrogen cyanide has been manufactnied from sodium cyanide and mineial acid, and from formamide by catalytic dehydration. As of this writing. 

In water, hydrogen cyanide and cyanide ion exist in equilibrium with their relative concentrations primarily dependent on pH and temperature. At pH <8, >93% of the free cyanide in water will exist as undissociated hydrogen cyanide (Towill et al. 1978). Hydrogen cyanide is hydrolyzed to formamide which is subsequently hydrolyzed to ammonium and formate ions (Callahan et al. 1979). However, the relatively slow rates of hydrolysis reported for hydrogen cyanide in acidic solution (Kreible and McNally 1929 Kreible and Peiker 1933) and of cyanides under alkaline conditions (Wiegand and Tremelling 1972) indicate that hydrolysis is not competitive with volatilization and biodegradation for removal of free cyanide from ambient waters (Callahan et al. 1979). 

Aside from the N-compounds listed above, a number of low-molecular-weight N compounds were also identified. [17] These included ammonia, hydrogen cyanide, dinitrogen (N2), nitric oxide (NO), methylamine, nitrous oxide (N20), formamide, acetamide, and N, N-dimethylmethanamine. 

Diphenylamine (m.p. 53) Formamide (Iso-optic) Hydrogen cyanide Five Methyl esters [Pg.62]

This method is a modification of the procedure described by Taylor and Ehrhart.2 Formamidine has previously been prepared (as its hydrochloride) from hydrogen cyanide via the formimino ether, which is then treated with ammonia,3 or by desulfurization of thiourea in the presence of ammonium chloride.4 The methosulfate salt of formamidine has been reported to be formed by reaction of formamide with dimethyl sulfate.8... 

Bottles containing a modified Karl Fischer reagent with formamide replacing methanol developed gas pressure during several months and burst. No reason was apparent, but slow formation of sulfuric acid, either by absorption of external water or by dehydration of some of the formamide to hydrogen cyanide, and liberation of carbon monoxide from the formamide seems a likely sequence. 

Abb. 7.16. Ritter reaction part I (cf. Fig. 7.17) SN1 reaction between a tertiary alcohol and a nucleophile containing C=N, with hydrogen cyanide acting as the nucleophile. Under reaction conditions the C=N group is tert-alkylated at the N atom and hydrated at the nitrile nitrogen leading to the formation of an W-tert-alkyl-formamide (B). 

Formamide (HCONH2) is another potential biosolvent. Formamide is formed by the reaction of hydrogen cyanide with water both are abundant in the cosmos. Like water, formamide has a large dipole moment and is an excellent solvent for almost anything that dissolves in water, including polyelectrolytes. In particular, formamide is able to dissolve RNA, DNA, and proteins, as well as their precursors. Formamide is not reactive like water. Indeed, many species that are thermodynamically unstable in water with respect to hydrolysis, are stable in formamide. 

The mechanism of adenine formation under presumed abiotic conditions (see Section 4.09.7.2) from hydrogen cyanide and formamide has also been investigated in an elegant series of experiments by detection of coupling contants (78JA4617). Thus when... 

The Ritter reaction proceeds by a nucleophilic addition of hydrogen cyanide followed by the hydrolysis of the intermediate formamide. Higher tertiary alkyl amines are produced using the same method with higher alkenes and alcohol. This is considered the most practical way to produce tertiary amines [99]. 

Adenine, C5H5N5, is formally a pentamer of hydrogen cyanide and indeed can be produced in the laboratory by the reaction of ammonia and hydrogen cyanide, although not with great efficiency. A related and more practical method involves the dehydration of formamide. Purine itself can also be obtained from formamide. ... 

The formamides resulting from the use of hydrogen cyanide can be particularly easily hydrolysed to the amines, thus providing an elegant method for synthesis of tertiary alkylamines that are otherwise difficult of access.21 The reaction is capable of very wide generalization and is suitable also for the preparation of other classes of compound such as A-acylamino acids,23 isoquinolines,24 and oxazolines.25... 

The reaction of P3N3CI3 with formamide in ether solution is known to release hydrogen chloride and hydrogen cyanide, giving trimetaphosphimic acid the analogous reaction with thioformamide is slower but the addition of pyridine speeds the process to give trimetathiophosphimic acid (89). 

The spontaneous, prebiotic formation of purines from hydrogen cyanide or formamide is a fascinating subject. Adenine is formally the pentamer of hydrogen cyanide. 

Hydrogen cyanide is produced industrially by thermolysis of formamide, or from methane and ammonia on platinum-rhodium catalysts (following a process developed by Leonid Andrussow (1896-1988) in 1927 at BASF in Ludwigs-hafen) (Fig. 5.196). 

Dimethylamine Dimethyl formamide Dimethylolpropionic acid 2,2-Dimethylpropanol Diphenylamine Ethylene chlorohydrin Hydrogen cyanide Hydroquinone monomethyl ether Isoquinoline Methyl isocyanate Nonanoic acid Phenolsulfonic acid Phosphorus oxychloride Pyrrole Quinaldine Sodium nitrate Stannic chloride Strontium salicylate Thioglycolic acid o-Xylene 2,3-Xylenol 2,3-Xylidine pharmaceutical mfg., orals Candelilla (Euphorbia cerifera) wax Cholecalciferol Ergocalciferol pharmaceutical mfg., parenterals Cholecalciferol Ergocalciferol pharmaceutical processing Chlorotrifluoromethane pharmaceutical prods. 

Scheme 6.41. A representation of the Ritter reaction. Hydrolysis of the iminium ion produces either an amide (as shown for reaction with hydrogen cyanide [HCN] producing the formamide of 2-amino-2-methylpropane [At-ferf-butylformamide (CHslsCNHCHO]) or, further, past the amide to the amine (2-amino-2-methylpropane [2-methyl-2-propananiine, f-butylamine, (CH3)3CNH2] and the corresponding (unspecified and thus unnamed) carboxylic acid (R-CO2H).

Hydrogen cyanide —, elimination of — s. De-hydrocyanation Hydrogen fluoride/boron fluoride 16, 833 Hydrogen halide acceptor, formamide as — 16,174 Hydrogen iodide 16, 570, 627, 983 17,18,32,119 Hydrogenolysis (s. a. Hydrocarbons, Replacement by hydrogen)... 

---