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By reduction of amides

High yields of amines have also been obtained by reduction of amides with an excess of magnesium aluminum hydride (yield 100%) [577], with lithium trimethoxyaluminohydride at 25° (yield 83%) [94] with sodium bis(2-methoxy-ethoxy)aluminum hydride at 80° (yield 84.5%) [544], with alane in tetra-hydrofuran at 0-25° (isolated yields 46-93%) [994, 1117], with sodium boro-hydride and triethoxyoxonium fluoroborates at room temperature (yields 81-94%) [1121], with sodium borohydride in the presence of acetic or trifluoroacetic acid on refluxing (yields 20-92.5%) [1118], with borane in tetrahydrofuran on refluxing (isolated yields 79-84%) [1119], with borane-dimethyl sulflde complex (5 mol) in tetrahydrofuran on refluxing (isolated yields 37-89%) [1064], and by electrolysis in dilute sulfuric acid at 5° using a lead cathode (yields 63-76%) [1120]. [Pg.167]

We ve already seen in Sections 21.7 and 21.8 bow amines can be prepared by reduction of amides and nitriles with l.tAlHf. The two-step sequence of S 2 displacement with CN" followed by reduction i an excellent method for (inverting an alky] halide into a primary alkylamine having one more carbon atom. Amide reduction provides an excellent method for converting... [Pg.987]

Primary amines are not usually made by reduction of amides (15) but by other reductive processes which are minor variations on this scheme. For unbranched amines (16) we can reduce cyanides. This method is especially suitable for benzylic amines since aryl cyanides (17) can be made from diazonium salts (see Chapter 2), and for the homologous amines (18) since cyanide ion reacts easily with benzyl halides. [Pg.68]

In close analogy, many proline derived diamines were prepared by reduction of amides of proline2,7-l3. [Pg.9]

Further examples of the preparation of N-alkyl amines by reduction of amides are included in section 96 (Amines from Amides)... [Pg.246]

Aldehydes are more generally prepared by electrolytic reduction of amides, the reduction of carboxylic adds being possible only when they are activated by a strongly electron-withdrawing group (58). [Pg.525]

The preparation of amines by the methods described m this section involves the prior synthesis and isolation of some reducible material that has a carbon-nitrogen bond an azide a nitrile a nitro substituted arene or an amide The following section describes a method that combines the two steps of carbon-nitrogen bond formation and reduction into a single operation Like the reduction of amides it offers the possibility of prepar mg primary secondary or tertiary amines by proper choice of starting materials... [Pg.934]

Reduction of amides (Section 22 9) Lithi um aluminum hydride reduces the car bonyl group of an amide to a methylene group Primary secondary or tertiary amines may be prepared by proper choice of the starting amide R and R may be ei ther alkyl or aryl... [Pg.957]

AletalHydrides. Metal hydrides can sometimes be used to prepare amines by reduction of various functional groups, but they are seldom the preferred method. Most metal hydrides do not reduce nitro compounds at all (64), although aUphatic nitro compounds can be reduced to amines with lithium aluminum hydride. When aromatic amines are reduced with this reagent, a2o compounds are produced. Nitriles, on the other hand, can be reduced to amines with lithium aluminum hydride or sodium borohydride under certain conditions. Other functional groups which can be reduced to amines using metal hydrides include amides, oximes, isocyanates, isothiocyanates, and a2ides (64). [Pg.263]

SONN MULLER Aldehyde synthesis Aldehyde synthesis from amides or ketoximes, by reduction of irmno chiondes. [Pg.355]

A series of amides has been prepared as protective groups that are cleaved by intramolecular cyclization after activation, by reduction of a nitro group, or by activation by other chemical means. These groups have not found much use since the first edition of this volume and are therefore only listed for completeness. The concept is generalized in the following scheme ... [Pg.356]

Acylation of a sulfonamide on the amide nitrogen serves to remove the sometimes objectionable taste of these drugs. Reac-I ion of intermediate, 154, with acetic anhydride followed by reduction of the nitro group affords acetyl methoxyprazine (156). The last, which has much the same biologic action as Mie parent compound, is used for oral administration in syrups. [Pg.131]

A heterocyclic ring may be used in place of one of the benzene rings without loss of biologic activity. The first step in the synthesis of such an agent starts by Friedel-Crafts-like acylation rather than displacement. Thus, reaction of sulfenyl chloride, 222, with 2-aminothiazole (223) in the presence of acetic anhydride affords the sulfide, 224. The amine is then protected as the amide (225). Oxidation with hydrogen peroxide leads to the corresponding sulfone (226) hydrolysis followed by reduction of the nitro group then affords thiazosulfone (227). ... [Pg.141]

Preparation of the aldehyde required for the synthesis of cyclothiazide (182) starts by carbonation of the Grignard reagent obtained from the Diels-Alder adduct (186) from allyl bromide and cyclopentadiene.The resulting acid (187) is then converted to the aldehyde (189) by reduction of the corresponding diethyl amide (188) with a metal hydride. [Pg.359]

Replacement of chlorine on the pendant benzoyl group by azide is apparently consistent with antiinflammatory activity. Acylation of indomethacin intermediate with p-nitrobenzoyl chloride leads to the corresponding amide (7). Saponification ( ) followed by reduction of the nitro group gives the amine 9. The diazonium salt (10) obtained on treatment with nitrous acid is then reacted with sodium azide there is thus obtained zidomethacin (11). [Pg.166]

Condensation of adipic acid derivative 17 with phenylethylamine in the presence of carbo-nyldiimidazole affords the bis-adipic acid amide 18. The synthesis is completed by reduction of the carbonyl groups with diborane followed by demethylation of the aromatic methoxy groups with hydrogen bromide the afford dopexamine (19) [3]. [Pg.22]

In some molecules, the loss of halogen is unexpectedly facile and may occur extensively even over platinum, as illustrated by reduction of the dihydro-2-benzazepine 4 to 5. The authors (5i) raised the possibility that such facile loss of halogen may involve neighboring-group assistance from the amide moiety. [Pg.149]


See other pages where By reduction of amides is mentioned: [Pg.69]    [Pg.282]    [Pg.74]    [Pg.26]    [Pg.15]    [Pg.15]    [Pg.69]    [Pg.282]    [Pg.74]    [Pg.26]    [Pg.15]    [Pg.15]    [Pg.28]    [Pg.350]    [Pg.18]    [Pg.43]    [Pg.561]    [Pg.133]    [Pg.1277]    [Pg.113]    [Pg.98]    [Pg.958]    [Pg.615]   
See also in sourсe #XX -- [ Pg.1550 ]




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