Nomenclature amides

In amides, the amino group is directly bonded to the carbonyl group. Amide nomenclature includes the simple suffix -amide. In secondary and tertiary amides, the substituents that are bound to the nitrogen atom are not labeled by the number, but by the letter N. The representative examples are A-methylmethanamide or N,N- dimethylmethanamide in the above scheme. Some amides which are derivatives of formic or of acetic acids also bear traditional names as formamide or acetamide. 

This chapter concerns the preparation and reactions of acyl chlorides acid anhydrides thioesters esters amides and nitriles These com pounds are generally classified as carboxylic acid derivatives and their nomenclature is based on that of carboxylic acids... 

The nomenclature (qv) of polyamides is fraught with a variety of systematic, semisystematic, and common naming systems used variously by different sources. In North America the common practice is to call type AB or type AABB polyamides nylon-x or nylon-respectively, where x refers to the number of carbon atoms between the amide nitrogens. For type AABB polyamides, the number of carbon atoms in the diamine is indicated first, followed by the number of carbon atoms in the diacid. For example, the polyamide formed from 6-aminohexanoic acid [60-32-2] is named nylon-6 [25038-54-4], that formed from 1,6-hexanediamine [124-09-4] or hexamethylenediamine and dodecanedioic acid [693-23-2] is called nylon-6,12 [24936-74-1]. In Europe, the common practice is to use the designation "polyamide," often abbreviated PA, instead of "nylon" in the name. Thus, the two examples above become PA-6 and PA-6,12, respectively. PA is the International Union of Pure and AppHed Chemistry (lUPAC) accepted abbreviation for polyamides. 

Because the rules for organic nomenclature determine the priority of naming different carbon chains from their relative lengths, the systematic names for type AABB polyamides depend on the relative length of the carbon chains between the amide nitrogens and the two carbonyl functions of the polymer for aUphatic nylon-Ayy, when x < the lUPAC name is poly[imino-R imino(l2y-dioxo-R )]. When x > then the name is... 

Table 1. Primary Fatty Amide (RCONf ) Nomenclature...

Tervalent organophosphorus compounds containing one single P-N bond with the valency of each atom saturated by protons or carbons (but no other heteroatoms) have been known since their discovery by MichaeUs more than one century ago [ 1 ] and named indistinctly as aminophosphanes, phosphanamines, phosphazanes, or phosphinous amides. This last chemical nomenclature is the one used by the Chemical Abstracts Service (CAS) for indexing these compounds and is also the one that best delimits the scope of this review those species derived from the parent H2P-NH2 (phosphinous amide in CAS nomenclature) by partial or total substitution of protons by hydrocarbon radicals (Table 1). 

Also covered by this review are those compounds bearing two or three phosphane units at the same N atom, that is those derived from (H2P)2NH (N-phosphino phosphinous amide in CAS nomenclature) and from (H2P)3N, NJsl-bis(phosphino) phosphinous amide, but not those bearing more than one amino... 

Base hydrolysis of amides also requires quite vigorous conditions, but mechanistically it is exactly equivalent to base hydrolysis of esters. After nucleophilic attack of hydroxide on to the carbonyl, the tetrahedral anionic intermediate is able to lose either an amide anion (care with nomenclature here, the amide anion is quite different from the amide molecule) or hydroxide. Although loss of hydroxide is preferred, since the amide anion is a stronger base than hydroxide, this would merely reverse the reaction. 

We observed that cyclic esters (lactones) may be formed when the carboxyl electrophile and hydroxyl nucleophile are in the same molecule (see Section 7.9.1). Similarly, cyclic amides are produced when carboxyl and amine groups are in the same molecule, and are again most favoured when this results in the generation of strain-free five- or six-membered rings. Cyclic esters are termed lactones, whereas cyclic amides are in turn called lactams. The nomenclature of lactams is similar... 

In Chapter 9 you see the basic structure of each of the carboxylic acids and Ccirboxylic acid derivatives. In this chapter we focus on the carboxylic acids and related compounds, such as esters, acyl chlorides, and acid anhydrides, and we also include some information on amides (see Chapter 13 for an additional examination of cimides). Before you can get into synthesis and reactions, though, you need to understand the structure and nomenclature of these compounds. 

Substrate specificity. Like most other enzymes, proteases display distinct preferences for certain substrates. These are often discussed using the nomenclature of Fig. 12-14. The substrate residue contributing the carbonyl of the amide group to be cleaved is designated Pj and residues toward the N terminus as P2, P3, etc., as is shown in Fig. 12-14. Residues toward the C terminus from the peptide linkage to be cleaved are designated P P etc. Chymotrypsin acts... 

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