2- Amino-2-butyl-1,1 -diethoxy

However, this multistep procedure is experimentally complex. A simpler variation described in 199127 consists of the reaction of an aldehyde and a nitro compound in the presence of triethylamine, TBAF and tert-butyl-dimethylsilyl chloride. Under these conditions, nitro sugars are obtained in good yieds and higher diastereoselectivities than those afforded by the standard conditions. This procedure was used in several synthesis of 2-nitro-2-deoxyaldoses, as for the condensation of l,l-diethoxy-2-nitroethane and l,2 3,4-di-0-isopropylidene-a-D-galacto-hexodialdo-l,5-piranose.28 More recently, it was applied to the addition of ethyl nitroacetate to the D-glucose derived aldehyde 18, to give nitro sugar derivatives 26, key precursors of polysubstituted cyclohexane a-amino acids (Scheme 10).29... 

Amino-l,l-diethoxy-butan bzw. 5-Amino-1,1-diethoxy-pentan. Die so entstehenden 4-(4,4-Diethoxy-butyl)- bzw. 4-(5,5-Diethoxy-pentyl)-(3-oxo-alkyl)-amine sind Vorstufen zu Indolizidin- bzw. Chinolizidin-Derivaten man extrahiert sie aus dem Reaktionsgemisch mit verdiinnter Salzsaure und bewirkt den RingschluB durch Erhitzen dieses sauren Extraktes4. 

Diethoxypyrazine (87) gave the unisolated dihydro adduct (88), and thence racmic-2-butyl-3,6-diethoxy-2,5-dihydropyrazine (89) (BuLi, Et2NCH2CH2NEt2, THF, -70°C, 3 h then pH 7 buffer 75%) this underwent normal Schollkopf lithiation/alkylation at the 5-position but the product and derived amino acid were naturally both racemic.539... 

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See also in sourсe #XX -- [ ]

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