3 research outputs found
En Route to 2‑(Cyclobuten-1-yl)-3-(trifluoromethyl)‑1<i>H</i>‑indole
A six-step
synthetic route from 4-chloro-2-methylaniline to 5-chloro-2-(cyclobut-1-en-1-yl)-3-(trifluoromethyl)-1<i>H</i>-indole (<b>1</b>) has been reported. Compound <b>1a</b> is a key impurity of reverse transcriptase inhibitor efavirenz,
an important anti-HIV/AIDS drug. Synthetic challenges, dead ends,
and detours are discussed
Regioselective Hydrolysis and Transesterification of Dimethyl 3‑Benzamidophthalates Assisted by a Neighboring Amide Group
An efficient, highly
regioselective hydrolysis and transesterification
of dimethyl 3-benzamidophthalates into the corresponding carboxylic
acid monoesters and mixed esters (including <i>tert</i>-butyl
esters) under basic conditions is presented. The selectivity is governed
by the neighboring 3-benzamido moiety’s participation and by
the nature of the solvent. In alcohols the reaction occurred exclusively
at the <i>ortho</i>-position to the benzamido functionality,
in pyridine or acetonitrile at both ester groups. An insight into
the mechanistic pathway was obtained from a <sup>1</sup>H NMR study
in perdeuteromethanol
A Way to Avoid Using Precious Metals: The Application of High-Surface Activated Carbon for the Synthesis of Isoindoles via the Diels–Alder Reaction of 2<i>H</i>-Pyran-2-ones
The application of activated carbon (Darco KB) for the
acceleration
and direction of the transformation of various 2<i>H</i>-pyran-2-ones with <i>N</i>-substituted maleimides toward
isoindole derivatives through the reaction sequence cycloaddition/elimination/dehydrogenation
is described. In this reaction, the catalyst mainly influences the
dehydrogenation step, which is essential to avoid the formation of
bicyclo[2.2.2]octenes as the other possible products. We found that
the combination of Darco KB, as the metal-free catalyst, and decalin,
as the solvent in a closed vessel, represents the most successful
conditions. A comparison of the effect of various dehydrogenation
catalysts and reaction conditions is also presented. In addition,
we have proven that the aromatization occurs via a hydrogen transfer
from the cyclohexadiene intermediate to the maleimide derivative (therefore
producing succinimides). This transfer is facilitated by the active
surface of the heterogeneous carbon-based catalyst