Amides, Cyclic lactams

The polymerization of lactams (cyclic amides) can be initiated by bases, acids, and water [Reimschuessel, 1977 Sebenda, 1976, 1978 Sekiguchi, 1984]. Initiation by water, referred to as hydrolytic polymerization, is the most often used method for industrial polymerization of lactams. Anionic initiation is also practiced, especially polymerization in molds to directly produce objects from monomer. Cationic initiation is not useful because the conversions and polymer molecular weights are considerably lower. 

Box 3.3 Effect of Ring Strain on the Carbonyl Stretching Frequencies of Lactones (Cyclic Esters) and Lactams (Cyclic Amides)... 

Bose AK, Manhas MS, Banik BK, Srirajan V (2000) In Greenberg A, Breneman CM, Liebman JF (eds) The amide linkage selected structural aspects in chemistry, biochemistry, and material science. Wiley, New York, pp 157—214. Chapter 7 (P-Lactams Cyclic Amides of Distinction)... 

Lactams (cyclic amides) See Organic Nitrogen Compounds... 

Lactams Cyclic amides are called lactams. Lactams are formed from amino acids, where the amino group and the carboxyl group have joined to form an amide. Lactams are named like lactones, by adding the term lactam at the end of the IUPAC name of the parent acid. Common names of lactams are formed by changing the -ic acid ending of the amino acid to -olactam. 

Lactones and Lactams Unstrained lactones (cyclic esters) and lactams (cyclic amides) absorb at typical frequencies for esters and amides. Ring strain raises the carbonyl absorption frequency, however. Recall that cyclic ketones with five-membered or smaller rings show a similar increase in carbonyl stretching frequency (Section 18-5A). Figure 21-5 shows the effect of ring strain on the C=0 stretching frequencies of lactones and lactams. 

H terocycle aren t new at thU point we ve encountered them many timea in previous chapters, usually without comment. Thus, epoxides (three-membered cyclic ethersi, lactones tcyclic esters), and lactams (cyclic amides are heterocyeles, as are the solvents tetrahydrofuran (a cyclic ether) end pyridine (an eromatic cycli< amiiK. ). in adUitiuii, cuibuhydrates exist as heterocyclic liemiacetals (Section 25.5). 

Lactams - Cyclic amides of amino carboxylic acids, having a 1-azacycloalkan-2-one structure, or analogues having unsaturation or heteroatoms replacing one or more carbon atoms of the ring. [5]... 

Polyamides contain the amide group —NH—CO— and can be classified in two homologous series. In the Perlon series, monomeric and repeat units are identical, since these polyamides occur either by the polymerization of lactams (cyclic amides) or the polycondensation of co-amino carboxylic acids. In contrast, the polyamides in the Nylon series are formed by the poly condensation of diamines and dicarboxylic acids Thus, two monomeric units form one repeat unit. 

Acid anhydride Acyl phosphate II II 0 0 0 II w/ r p -oic anhydride -yl phosphate Lactam (cyclic amide) O II w None... 

Greenberg, A., Breneman, C.M., and Liebman, J.F. (2000) -Lactams Cyclic Amides of Distinction, John Wiley Sons, Inc., New York, p. 157. 

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