61413-54-5Relevant articles and documents
Enantioselective Flow Synthesis of Rolipram Enabled by a Telescoped Asymmetric Conjugate Addition-Oxidative Aldehyde Esterification Sequence Using in Situ-Generated Persulfuric Acid as Oxidant
Nagy, Bence S.,Llanes, Patricia,Pericas, Miquel A.,Kappe, C. Oliver,?tv?s, Sándor B.
, (2022/02/05)
A novel approach is reported for the enantioselective flow synthesis of rolipram comprising a telescoped asymmetric conjugate addition-oxidative aldehyde esterification sequence followed by trichlorosilane-mediated nitro group reduction and concomitant la
General access to C-centered radicals: Combining a bioinspired photocatalyst with boronic acids in aqueous media
Bloom, Steven,Chilamari, Maheshwerreddy,Immel, Jacob R.
, p. 12727 - 12737 (2020/11/18)
Carbon-centered radicals are indispensable building blocks for modern synthetic chemistry. In recent years, visible light photoredox catalysis has become a promising avenue to access C-centered radicals from a broad array of latent functional groups, including boronic acids. Herein, we present an aqueous protocol wherein water features a starring role to help transform aliphatic, aromatic, and heteroaromatic boronic acids to C-centered radicals with a bioinspired flavin photocatalyst. These radicals are used to deliver a diverse pool of alkylated products, including three pharmaceutically relevant compounds, via open-shell conjugate addition to disparate Michael acceptors. The mechanism of the reaction is investigated by computational studies, deuterium labeling, radical-trapping experiments, and spectroscopic analysis.
Divergent Synthesis of γ-Amino Acid and γ-Lactam Derivatives from meso-Glutaric Anhydrides
Connon, Stephen J.,Craig, Ryan,Smith, Simon N.
supporting information, p. 13378 - 13382 (2020/10/02)
The first divergent synthesis of both γ-amino acid and γ-lactam derivatives from meso-glutaric anhydrides is described. The organocatalytic desymmetrisation with TMSN3 relies on controlled generation of a nucleophilic ammonium azide species mediated by a polystyrene-bound base to promote efficient silylazidation. After Curtius rearrangement of the acyl azide intermediate to access the corresponding isocyanate, hydrolysis/alcoholysis provided uniformly high yields of γ-amino acids and their N-protected counterparts. The same intermediates were shown to undergo an unprecedented decarboxylation–cyclisation cascade in situ to provide synthetically useful yields of γ-lactam derivatives without using any further activating agents. Mechanistic insights invoke the intermediacy of an unconventional γ-N-carboxyanhydride (γ-NCA) in the latter process. Among the examples prepared using this transformation are 8 APIs/molecules of considerable medicinal interest.
Deacetylative Amination of Acetyl Arenes and Alkanes with C-C Bond Cleavage
Hyodo, Kengo,Hasegawa, Genna,Maki, Hiroya,Uchida, Kingo
, p. 2818 - 2822 (2019/04/25)
The Br?nsted acid-catalyzed synthesis of primary amines from acetyl arenes and alkanes with C-C bond cleavage is described. Although the conversion from an acetyl group to amine has traditionally required multiple steps, the method described herein, which uses an oxime reagent as an amino group source, achieves the transformation directly via domino transoximation/Beckmann rearrangement/Pinner reaction. The method was also applied to the synthesis of γ-aminobutyric acids, such as baclophen and rolipram.
Assembling of medium/long chain-based β-arylated unnatural amino acid derivatives via the Pd(II)-catalyzed sp3 β-C-H arylation and a short route for rolipram-type derivatives
Tomar, Radha,Bhattacharya, Debabrata,Babu, Srinivasarao Arulananda
, p. 2447 - 2465 (2019/03/26)
In this paper, we report the assembling of libraries of β-arylated short/medium/long chain-based non-α-amino acid (aminoalkanoic acid) derivatives via the Pd(II)-catalyzed, bidentate directing group 8-aminoquinoline-aided sp3 β-C-H activation/arylation method. Short/medium chain-based unnatural amino acid derivatives containing an aryl group at the β-position are promising small molecules with therapeutic properties. Thus, it is necessary to enrich the libraries of short/medium/long chain-based unnatural amino acid derivatives containing an aryl group at the β-position. Considering the importance of β-arylated short/medium/long chain-based non-α-amino acid derivatives, an inclusive attention was paid to explore the Pd(II)-catalyzed sp3 β-C-H arylation of short/medium/long chain-based non-α-amino acids. Representative synthetic transformations including a short route for the assembling of rolipram and related compounds and 3-arylated GABA derivatives such as, baclofen, phenibut and tolibut were shown using selected β-C-H arylated non-α-amino acid derivatives.
Catalytic Intermolecular Carboamination of Unactivated Alkenes via Directed Aminopalladation
Liu, Zhen,Wang, Yanyan,Wang, Zichen,Zeng, Tian,Liu, Peng,Engle, Keary M.
, p. 11261 - 11270 (2017/08/22)
An intermolecular 1,2-carboamination of unactivated alkenes proceeding via a Pd(II)/Pd(IV) catalytic cycle has been developed. To realize this transformation, a cleavable bidentate directing group is used to control the regioselectivity of aminopalladation and stabilize the resulting organopalladium(II) intermediate, such that oxidative addition to a carbon electrophile outcompetes potential β-hydride elimination. Under the optimized reaction conditions, a broad range of nitrogen nucleophiles and carbon electrophiles are compatible coupling partners in this reaction, affording moderate to high yields. The products of this reaction can be easily converted to free ?3-amino acids and ?3-lactams, both of which are common structural motifs found in drug molecules and bioactive compounds. Reaction kinetics and DFT calculations shed light on the mechanism of the reaction and explain empirically observed reactivity trends.
Direct Catalytic Desaturation of Lactams Enabled by Soft Enolization
Chen, Ming,Dong, Guangbin
supporting information, p. 7757 - 7760 (2017/06/21)
A direct catalytic method is described for the α,β-desaturation of N-protected lactams to their conjugated unsaturated counterparts under mildly acidic conditions. The reaction is consistently operated at room temperature and tolerates a wide range of functional groups, showing reactivity complementary to that of prior desaturation methods. Lactams with various ring sizes and substituents at different positions all reacted smoothly. The synthetic utility of this method is demonstrated in a concise synthesis of Rolipram. In addition, linear amides also prove to be competent substrates, and the phthaloyl-protected product serves as a convenient precursor to access various conjugated carboxylic acid derivatives. Strong bases are avoided in this desaturation approach, and the key is to merge soft enolization with a Pd-catalyzed oxidation process.
N-Cyanation of Secondary Amines Using Trichloroacetonitrile
Ayres, James N.,Ling, Kenneth B.,Morrill, Louis C.
, p. 5528 - 5531 (2016/11/17)
A one-pot N-cyanation of secondary amines has been developed using trichloroacetonitrile as an inexpensive cyano source. A diverse range of cyclic and acyclic secondary amines can be readily transformed into the corresponding cyanamides in good isolated yields, with the method successfully utilized in the final synthetic step of a biologically active rolipram-derived cyanamide. This approach exhibits distinct selectivity when compared to the use of highly toxic cyanogen bromide.
Multisite organic-inorganic hybrid catalysts for the direct sustainable synthesis of GABAergic drugs
Leyva-Perez, Antonio,Garcia-Garcia, Pilar,Corma, Avelino
supporting information, p. 8687 - 8690 (2014/08/18)
Multisite organic-inorganic hybrid catalysts have been prepared and applied in a new general, practical, and sustainable synthetic procedure toward industrially relevant GABA derivatives. The domino sequence is composed of seven chemical transformations which are performed in two one-pot reactions. The method produces both enantiomeric forms of the product in high enantiopurity as well as the racemate in good yields after a single column purification step. This protocol highlights major process intensification, catalyst recyclability, and low waste generation.
From paracetamol to rolipram and derivatives: Application of deacetylation-diazotation sequences and palladium-catalyzed matsuda-heck reaction
Schmidt, Bernd,Elizarov, Nelli,Berger, Rene,Petersen, Monibh.
, p. 1174 - 1180 (2013/06/05)
A six-step synthesis of the antidepressant rolipram from the popular analgetic 4-acetamidophenol (paracetamol) is described. The steps include oxidative functionalization of the aromatic core, diazonium salt formation via deacetylation-diazotation, Matsuda-Heck reaction, conjugate addition of nitromethane, and hydrogenative cyclization. Georg Thieme Verlag Stuttgart · New York.
