Pyrolysis carboxylic acid amides

Without additional reagents Isocyanates from carboxylic acid amides by pyrolysis... 

Pyranylammonium salts, tetrahydro-, quaternary —, pyrolysis 18, 959 Pyranylation of carboxylic acid amides 18, 385 2-Pyranyl derivatives, tetrahydro- s. a. Pyranylation... 

Reactions of the carboxyl group include salt and acid chloride formation, esterification, pyrolysis, reduction, and amide, nitrile, and amine formation. Salt formation occurs when the carboxyUc acid reacts with an alkaline substance (22)... 

Other examples of the use of intramolecular Diels-Alder reactions in preparative chemistry have appeared the o-quinodimethane (186), produced as a transient intermediate in the pyrolysis of the analogous benzocyclobutene, cyclizes to give (187 65%), the desulphurization of which (Raney nickel) affords a potential intermediate for the preparation of tetracyclic diterpenes. Elevated temperatures result in the isomerization of (188) into the internal [4 -I- 2] adduct (189) in which it is clear that a cyano-group has acted as a dienophile (189) is the result of a subsequent double-bond shift, and the structure was validated by crystallographic structure analysis. Bridged y-lactams have been successfully prepared by the intramolecular Diels-Alder reactions of NN-diallyl- and iV-(l,l-dimethylprop-2-yn-l-yl)amides of various penta-2,4-diene carboxylic acids. Thus, pyrolysis of (190) gave an 80%... 

Amines (Chapter 5, Part VI, and Chapter 10) are basic.Thus, their reactions with carboxylic acids produce the corresponding salts rather than amides (Equation 9.97). Although it is possible for some amine salts of carboxylic acids to be converted to the corresponding amides by heating them to high temperatures (pyrolysis), the fragile nature of many compounds prohibits such drastic treatment. 

MMA monomer, methanol, and carbon dioxide were detected in the pyrolysis gases. The profiles of rate of evolution against temperature were used to identify the presence of occluded monomer and thermally unstable end groups such as unsaturation. The evolution profiles for MMA and methanol were found to be characteristic for each type of crosslink. Evolution of methanol between 250 °C and 300 "C, and between 300 °C and 350 °C has been attributed to condensation reactions of carboxylic acid and primary amide groups, respectively, with adjacent ester groups. The evolution profiles were used to distinguish between samples from different manufacturers, and to identify material [5]. 

---