A New Selective Cleavage of N,N‐Dicarbamoyl‐Protected Amines Using Lithium Bromide.

Abstract

A New Selective Cleavage of N,N-Dicarbamoyl-Protected Amines Using Lithium Bromide. -Treatment of N,N-di-Boc-protected amines with LiBr offers a new, mild, and simple method to selective cleavage of one N-Boc group. Under these conditions no racemization is observed. LiBr is also effective for the selective deprotection of N-Boc-Tos and N-Cbz-Tos-protected amines. However, for selective deprotection of N-Boc-Ac and N-Boc-Cbz-protected amines the use of MgClO 4 is necessary. -(HERNANDEZ, J. N.; RAMIREZ, M. A.; MARTIN*, V. S.; J. Org. Chem. 68 (2003) 3, 743-746; Inst. Univ. Bio-Org., Univ. La Laguna, E-38206 La Laguna, Tenerife, Spain; Eng.) -Jannicke 24-167

Structure–Activity Relationships of Fish Oil Derivatives with Antiallergic Activity in Vitro and in Vivo

“…The reaction of 2-aminoethanol with di-tert-butyl dicarbonate in the presence of triethylamine as a base gave a N-protected ethanolamine intermediate, which was alkylated by using iodomethane in the presence of sodium hydride in N,N-dimethylformamide (DMF) to provide a Nprotected ether amine in 87% yield. 23 The protecting group of the ether amine was then removed by adding trifluoroacetic acid in dichloromethane to afford an ether amine, followed by coupling with DHA by using EDCI and DMAP in dichloromethane to make compound 24 in 82% yield. 22 Compound 25 was prepared in the same reactions as those used for the synthesis of compound 24 by using 2-(methylamino)ethanol as a starting material as shown in Scheme 4(II).…”

“…In order to see whether incorporating a substituent onto NH, OH, or the ethyl chain of the ethanolamide moiety affects antiallergic activity, a series of substituted derivatives were synthesized (23−31). When a methyl group was added to NH (23) or OH (24) of the ethanolamide moiety, no activity was induced. In compounds substituted with two methyl groups on both NH and OH (25), no significant activity was also observed, suggesting that substitution on the NH or OH group of the ethanolamide moiety is not favorable for improving potency and the hydrogen atoms on both the NH and OH groups play a highly important role in generating anti-degranulating activity.…”

Potent Inhibition of Nicotinamide N-Methyltransferase by Alkene-Linked Bisubstrate Mimics Bearing Electron Deficient Aromatics

“…The 13 C NMR spectra of the compounds recorded in D 2 O could not be referenced. Compounds 5 , 27 9 , 34 10 , 20 19a , 20 19b , 35 19c – d , 20 19e , 36 19f – g , 20 22a , 37 30 , 27 and 32 ( 38 ) were prepared as previously described and had NMR spectra and mass spectra consistent with the assigned structures. Purity was confirmed to be ≥95% by LCMS performed on a Shimadzu LC-20AD system with a Shimadzu Shim-Pack GISS-HP C18 column (3.0 × 150 mm, 3 μm) at 30 °C; the system was equipped with a UV detector, which monitored wavelengths at 214 and 254 nm.…”

Síntese de um intermediário indólico-piperidínico, visando a síntese total do ácido lisérgico

“…Este sinal característico do grupo diazo será de grande utilidade para a identificação das diazocetonas α,β-insaturadas, como será visto adiante. aldeído precursor 11 foi preparado em uma sequência de cinco etapas, mediante reações que já foram reportadas na literatura e que foram adaptadas para esta rota sintética[25][26][27][28][29] .No parágrafo anterior se mencionou uma descrição curta sobre a rota sintética para a construção do aldeído precursor 11(5 etapas a partir do Ltriptofano; 50% de rendimento global). A partir de agora, se fará uma descrição detalhada de cada etapa envolvida na rota descrita no Esquema 12.…”