40 Amines, Ammonium Salts, Amine N-Oxides, Haloamines, Hydroxylamines and Sulfur Analogues, and Hydrazines
Schaumann, E., Science of Synthesis, (2009) 40, 1.
General Introduction
This volume of Science of Synthesis covers the syntheses of compounds having a single bond between an sp3-hybridized carbon atom and a formally sp3-hybridized nitrogen substituent. As an aid to organization it has been split into two parts which are, respectively, Science of Synthesis, Volume 40a (Amines and Ammonium Salts) and Science of Synthesis, Volume 40b (Amine N-Oxides, Haloamines, Hydroxylamines and Sulfur Analogues, and Hydrazines). Among the product classes featured, one of the most prominent representatives is the aliphatic amines (Section 40.1); however, separate sections are devoted to propargylic (Section 40.1.2) and allylic amines (Section 40.1.3) for which special synthetic methods are available, or where special care must be taken to secure synthetic success. Similarly, compounds with more than one amino group or an additional phosphorus functionality are treated separately (Section 40.1.4), as are the obviously special small-ring amine derivatives aziridines (Section 40.1.5) and azetidines (Section 40.1.6). Furthermore, the amino group may be modified in the form of ammonium compounds or of N-ylides (“ammonioalkanides”; Section 40.1.7). There is also a wide range of functionalities where a parent amine structure is combined with one heteroatom. This type of compound is seen in nitroxyl radicals (nitroxides; Section 40.2), amine N-oxides (Section 40.3), N-haloamines (Section 40.4), hydroxylamines (“N-hydroxyamines”) in acyclic (Section 40.5) or in cyclic form (Section 40.6), and hydrazines, again in acyclic (Section 40.7) or in cyclic form (Section 40.8), as well as extended hydrazines (Section 40.9). Finally, amido derivatives of sulfur-derived acids, specifically of sulfanediol (Section 40.10), of sulfurous acid (Section 40.11), and of sulfuric acid (Section 40.12) are covered. Ammonium sulfonates, thiohydroxylamines, and aminosulfonium salts are also featured (Section 40.13). For a ready overview, these structures are compiled in Table 1.
Table 1 Classes of Amines and Amine Derivatives Covered in Volume 40
| Product Class or Subclass | Structure(s) | Section |
|---|---|---|
| amino compounds | 40.1 | |
| alkyl and cycloalkylamines |  |
40.1.1 |
| propargylic amines |  |
40.1.2 |
| allylic amines |  |
40.1.3 |
| n-nitrogen- or n-phosphorus-functionalized alkylamines (n ≥2) |  |
40.1.4 |
| aziridines |  |
40.1.5 |
| azetidines |  |
40.1.6 |
| ammonium compounds |  |
40.1.7.1.1–40.1.7.1.4 |
| nitrogen ylides |  |
40.1.7.1.5 |
| nitroxyl radicals (nitroxides) |  |
40.2 |
| amine N-oxides |  |
40.3 |
| N-haloamines |  |
40.4 |
| hydroxylamines |  |
40.5 |
| 1-oxa-2-azacycloalkanes |  |
40.6 |
| hydrazines and hydrazinium salts |  |
40.7 |
| 1,2-diazacycloalkanes |  |
40.8 |
| triazanes and tetrazanes |  |
40.9 |
| amido derivatives of sulfanediol |  |
40.10 |
| amido derivatives of sulfurous acid |  |
40.11.1–40.11.3 |
| N-(thio)sulfinylamines |  |
40.11.4, 40.11.5 |
| N,N′-dialkylsulfur diimides |  |
40.11.6 |
| N-alkylsulfamic acids and derivatives |  |
40.12 |
| ammoniumsulfonates, thiohydroxylamines, and aminosulfonium salts |  |
40.13 |
For a product class to be included in Volume 40, the hierarchy of Science of Synthesis requires that the carbon in the C—N bond is sp3 hybridized. The chemistry of ynamines 1 (X = CR3) is covered in Science of Synthesis, Vol. 24 [Three Carbon—Heteroatom Bonds: Ketene Acetals and Yne—X Compounds (Section 24.4.4.1)] and the chemistry of cyanamides 1 (X = N), where an sp-hybridized carbon is bonded to the nitrogen, is described in Vol. 18 [Four Carbon—Heteroatom Bonds: X—C≡X, X=C=X, X2C=X, CX4 (Section 18.1.4)]. If the carbon is sp2 hybridized, as in general structure 2, the products can be enamines 2 (X = CR4R5) {see Science of Synthesis, Vol. 33 [Ene—X Compounds (X = S, Se, Te, N, P) (Section 33.4.633.4.6)]} or amide-type derivatives 2 (X = O or heteroanalogues), covered as carbonic acid derivatives in Science of Synthesis, Vol. 18 (Four Carbon—Heteroatom Bonds: X—C≡X, X=C=X, X2C=X, CX4), and as carboxylic acid amides in Vol. 21 (Three Carbon—Heteroatom Bonds: Amides and Derivatives; Peptides; Lactams), and as their heteroanalogues in Vol. 22 (Three Carbon—Heteroatom Bonds: Thio-, Seleno-, and Tellurocarboxylic Acids and Derivatives; Imidic Acids and Derivatives; Ortho Acid Derivatives). Compounds 3 with an NR1 unit as a member of a heteroaromatic ring (n ≥1) are the subject of Category 2 (Hetarenes and Related Ring Systems; Vols. 9–17).
Aliphatic nitrogen compounds 4 with a double bond to another heteroatom are the subject of Science of Synthesis, Vol. 41 (Nitro, Nitroso, Azo, Azoxy, and Diazonium Compounds, Azides, Triazenes, and Tetrazenes) as are nitrogen functionalities with two other heteroatoms on the nitrogen as in 5 and 6. Compounds 6 (“nitroso acetals”) formally encompass derivatives 7 (X = Y = NR12). However, from another point of view, compounds 7 are extended hydrazines (“triazanes” when n = 1, “tetrazanes” when n = 2) and therefore are described here in Section 40.9
Based on the priority rules of Science of Synthesis, sp3 hybridization of the carbon in the C—N bond is not a sufficient criterion for inclusion in the present volume; in addition, no other heteroatom on the substituted carbon is allowed. Similarly, if another functional group of higher priority is present on the neighboring carbon, the synthesis is covered at the location of that group. Finally, compounds with nitrogen—metal bonds are covered in Category 1 (Organometallics; Vols. 1–8). An overview of the location of the different types of formal amino derivatives is given in Table 2. In any case, to get the full information that is available in Science of Synthesis on amino derivatives, a substructure search in the electronic version is recommended.
Table 2 Amino Group Containing Structural Units Covered Elsewhere in Science of Synthesis
| Name | Structure(s) | Volume | Section |
|---|---|---|---|
| aminoboranes, borane–amine complexes |  |
6 (Boron Compounds) | 6.1.15 |
| N-(dialkylboryl)amides |  |
6.1.29.3 | |
| amine–aluminate complexes | LiAlH4-n(NR1R2)n, LiAlH4•NR1R2R3 | 7 [Compounds of Groups 13 and 2 (Al, Ga, In, Tl, Be…Ba)] | 7.1.2.19 |
| alkylaluminium amides |  |
7.1.7 | |
| magnesium amides | (R1R2N)2Mg | 7.6.14 | |
| lithium amides | R1R2NLi | 8a [Compounds of Group 1 (Li…Cs)] | 8.1.6 |
| α-lithioamines |  |
8.1.21 | |
| potassium amides | R1R2NK | 8b [Compounds of Group 1 (Li…Cs)] | 8.3.2.3.2, 8.3.6 |
| orthocarbamic acid triesters |  |
18 (Four Carbon—Heteroatom Bonds: X—C≡X, X=C=X, X2C=X, CX4) | 18.16.3 |
| orthocarbonic acid diester diamides |  |
18.16.6 | |
| alkoxytriaminomethanes |  |
18.16.9 | |
| trithioorthocarbamic triesters |  |
18.16.11 | |
| dithioorthocarbonic acid diester diamides |  |
18.16.13 | |
| organosulfanyl-, and organoselanyltriaminomethanes |  |
18.16.15 | |
| orthocarbonic acid tetraamides |  |
18.16.17 | |
| 2-aminoalkanoic acids |  |
20a (Three Carbon—Heteroatom Bonds: Acid Halides; Carboxylic Acids and Acid Salts) | 20.2.7 |
| 3-aminoalkanoic acids |  |
20.2.13.1.3 | |
| 2-aminoalkanoic acid esters |  |
20b [Three Carbon—Heteroatom Bonds: Esters and Lactones; Peroxy Acids and R(CO)OX Compounds; R(CO)X, X = S, Se, Te] | 20.5.10 |
| 3-aminoalkanoic acid esters |  |
20.5.16.1.3 | |
| α,N-substituted alkanamides |  |
21 (Three Carbon—Heteroatom Bonds: Amides and Derivatives; Peptides; Lactams) | 21.5.3 |
| β,N-substituted alkanamides |  |
21.7.5 | |
| ortho amides |  |
22 (Three Carbon—Heteroatom Bonds: Thio-, Seleno, and Tellurocarboxylic Acids and Derivatives; Imidic Acids and Derivatives; Ortho Acid Derivatives) | 22.7.6 |
| 2-aminoaldehydes |  |
25 (Aldehydes) | 25.4.3 |
| α-amino ketones |  |
26 (Ketones) | 26.6.8 |
| N/X-acetals |  |
30 (Acetals: O/N, S/S, S/N, and N/N and Higher Heteroatom Analogues) | 30.1.1, 30.1.2, 30.4, 30.5.4, 30.5.5, 30.6, 30.7.1 |
| diaryl(aza)sulfonium salts |  |
31a [Arene—X (X = Hal, O, S, Se,Te)] | 31.15.4.1.3 |
| alkyl(aryl)(aza)sulfonium salts |  |
31.15.4.1.6 | |
| diaza(aryl)sulfonium salts |  |
31.15.4.1.9 | |
| arylamines |  |
31b [Arene—X (X = N, P)] | 31.28 |
| arylammonium salts |  |
31.29 | |
| N-haloarylamines |  |
31.32 | |
| N-arylhydroxylamines |  |
31.33 | |
| arylhydrazines |  |
31.34 | |
| cyclic arylamines |  |
31.38 | |
| β-fluoroamines |  |
34 (Fluorine) | 34.10 |
| β-chloro-, β-bromo-, and β-iodoamines |  |
35 (Chlorine, Bromine, and Iodine) | 35.1.5.1.10, 35.1.5.4, 35.2.5.1.6, 35.2.5.4, 35.3.5.1.4, 35.3.5.4 |
| β-amino alcohols |  |
36 (Alcohols) | 36.10.1.1.3, 36.10.1.1.6, 36.10.1.1.8, 36.10.1.1.14 |
| γ-amino alcohols |  |
36.10.2.1.2–36.10.2.1.5 | |
| β-amino thiols |  |
39 (Sulfur, Selenium, and Tellurium) | 39.5.1.7.1, 39.5.1.8 |
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