Benzylamides preparation

Benzyl-l,3-dioxo-l,2,3,4-tetrahydro-j8-carboline (189) was prepared by heating the benzylamide 188 with polyphosphoric acid on a... 

General methods for the preparation of a.jS-unsaturated iron-acyl complexes are deferred to Section D 1.3.4.2.5.1.1. examples of the alkylation of enolates prepared via Michael additions to ii-0 ,/ -unsaturated complexes prepared in situ are included here. Typical reaction conditions for these one-pot processes involve the presence of an excess of alkyllithium or lithium amide which first acts as base to promote elimination of alkoxide from a /f-alkoxy complex to generate the -a,)S-unsaturated complex which then suffers 1,4-nucleophilic addition by another molecule of alkyllithium or lithium amide. The resulting enolate species is then quenched with an electrophile in the usual fashion. The following table details the use of butyllithium and lithium benzylamide for these processes44,46. 

Several different types of linker have been developed that yield amides upon cleavage. These linkers can often also be used to prepare sulfonamides, carbamates, or ureas. There are essentially three different strategies for the release of amides from insoluble supports (a) cleavage of the benzylic C-N bond of resin-bound N-alkyl-N-benzylamides (backbone amide linkers, BAL linkers), (b) nucleophilic cleavage of resin-bound acylating agents with amines, and (c) acylation/debenzylation of resin-bound /V-benzyl-/V,A -dialkylamines. 

A mixture of A-formylglycine benzylamide (0.1 mol), phosphorus pentachloride (0.205 mol), and phosphorus oxychloride (40 ml) is cautiously prepared at room temperature. After 3-5 min the mixture warms spontaneously with foam formation as HCl(g) is evolved. Ice water is used to keep the temperature below 60°C. The mixture is then stirred (2h at 20-25°C and 3h at 55-60 C). After removal of the phosphoryl chloride under reduced pressure, the cooled residue is treated with crushed ice (50 g), neutralized with aqueous ammonia to pH 8-9, and extracted with chloroform (3 x 60 ml). The extracts are washed with water, dried over sodium sulfate, filtere d, the solvent evaporated, and the residue is vacuum distilled to give the product, b3 146-147°C (49%). 

The reaction of a primary amide and benzaldehyde, in the presence of a silane and trifluoroacetic acid, leads to the corresponding A -benzylamide. This transformation is a reductive alkylation. A-Alkynyl amides have been prepared by the cop-... 

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