Amines benzyloxycarbonyl

The same reagents can be used to form amides from carboxylic acids and amines, a method which is applicable to peptide synthesis. Condensation of A-benzyloxycarbonyl-L-phenylalanine and ethyl glycinate hydrochloride gave an 85% yield of purified dipeptide. 

The benzyloxycarbonyl protecting group for amines is introduced in high yield using benzyl imidazole-carboxylate with a catalytic amount (5%) of dimethylamino-pyridine.[1953... 

N-Acylation and 3-alkoxycarbonylation reactions may be achieved by conventional acylation procedures. A variety of 3-acyl derivatives 157 can be prepared most conveniently by the treatment of DPPOx 266 with carboxylic acids in the presence of a tertiary amine. tert-Butoxycarbonyl (Boc-Ox, 236) and benzyloxy carbonyl (Cbz-Ox, 267) (Cbz = benzyloxycarbonyl) compounds are of practical use for introduction of nitrogen protecting groups. ... 

The cascade hydroformylation-allylboration-hydroformylation of ( )-aminoallylborate 85 catalyzed by Rh(acac)(CO)2-BIPHEPHOS afforded oxazabicyclic lactol 87 via linear aldehyde 86 in 83% yield (Scheme 14)." The regioselective hydroformylation of 7-amidoallylboronate 88 gave linear aldehyde 89 which was in equilibrium with lactol 90. Removal of the benzyloxycarbonyl (Cbz) group by hydrogenolysis initiated another cascade process, that is, amination-hydro-genation, affording indolizidine 91 in 60% overall yield." ... 

A suspension of 0.76 g LAH in 50 mL anhydrous THF was stirred under an inert atmosphere, and treated with the dropwise addition of a solution of 2.27 g N-(benzyloxycarbonyl)tryptamine in 30 anhydrous THF. The reaction mixture was held at reflux for 40 min, then cooled to 40 °C and the excess hydride destroyed with the addition of 50% aqueous THF. The solids were removed by filtration, washed with THF, the filtrate and washings combined, and the solvent removed under vacuum. The residue was impure N-methyltryptamine (NMT) as could be used without purification in the following alkylation. The isolation, purification and characterization of this intermediate amine is described in the NMT recipe, and of course the pure NMT can be used in the following reductive alkylation. 

Boc) and 7V-(benzyloxycarbonyl) (Z) protective groups are stable under these conditions. In contrast to that, the jV-(4-methoxybenzyloxycarbonyI) (Moz) protecting group can readily be cleaved by the cation radical of tris(2,4-dibromophenyl)amine (Table 11, No. 13) ° >. 

The triethylamine salt of 2,2-dimethyl-3-(3,4-methylenedioxyphenyl)-propionic acid (5.4 g amine, 11.4 g acid) was dissolved in 10 mL 11,0 and diluted with sufficient acetone to maintain a clear solution at ice-bath temperature. A solution of 6.4 g ethyl chloroformate in 40 mL acetone was added to the 0 °C solution over the course of 30 min, followed by the addition of a solution of 4.1 g sodium azide in 30 mL H20. Stirring was continued for 45 min while the reaction returned to room temperature. The aqueous phase was extracted with 100 mL toluene which was washed once with H20 and then dried with anhy drou s Mg S04. Thi s org ani c sol uti on of the azide was heated on a steam bath until nitrogen evolution had ceased, which required about 30 min. The solvent was removed under vacuum and the residue was dissolved in 30 mL benzyl alcohol. This solution was heated on the steam bath overnight. Removal of the excess benzyl alcohol under vacuum left a residue 13.5 g of l-(N-(benzyloxycarbonyl)amino)-1,1 -dimethyl-2-(3,4-methylenedioxyphenyl)ethane as an amber oil. The dimethyl group showed, in the NMR, a sharp singlet at 1.30 ppm in CDCH,. Anal. (C19H2lN04) C,H. This carbamate was reduced to the primary amine (below) or to the methylamine (see under MDMP). 

The first procedure is the selective protection of an amine in the presence of an indole-NH group or an alcohol.14 Indole-NH (pKa = 17) shows a similar acidity to that of alcohols (pKa = 18). In the next step the benzyloxycarbonyl (CBZ) protected compound 26 is treated with di-fcrt-butyldicarbonate (B0C)20 and DMAP to form 27. Tert-butylchloroformate is unstable and therefore cannot be used for the preparation of BOC derivatives. Conversion of 10 with (B0C)20 in the presence of DMAP would lead to the double BOC protected compound 28. 

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