13669-35-7

Upstream product

• 94356-63-5 4-cyclohex-1-enyl-pyridine 
• 110-86-1 pyridine 
• 110-82-7 cyclohexane 
• 107264-18-6 C₂₀H₂₁NO₂ 
• 91-22-5 quinoline 
• 1122-54-9 methyl (4-pyridyl) ketone 
• 98-89-5 Cyclohexanecarboxylic acid 
• 91-19-0 2,3-diethynylquinoxaline 
• 491-35-0 C₆H₄NCH₂CHCCH₂ 
• 105398-69-4 Cyclohexanecarboxylic acid 2-thioxo-2H-pyridin-1-yl ester 
• 823-76-7 Cyclohexyl methyl ketone 
• 290-38-0 1,2,4-triazine 
• 76833-14-2 1-(1-Cyclohexyl-vinyl)-pyrrolidine 
• 110-83-8 cyclohexene 

Downstream Products

• 1012886-77-9 4-cyclohexyl-1-(2-phenyl-allyl)pyridinium bromide 
• 60601-62-9 4-cyclohexenylpiperidine hydrochloride 

Relevant academic research and scientific papers

Practical and Regioselective Synthesis of C-4-Alkylated Pyridines

The direct position-selective C-4 alkylation of pyridines has been a long-standing challenge in heterocyclic chemistry, particularly from pyridine itself. Historically this has been addressed using prefunctionalized materials to avoid overalkylation and mixtures of regioisomers. This study reports the invention of a simple maleate-derived blocking group for pyridines that enables exquisite control for Minisci-type decarboxylative alkylation at C-4 that allows for inexpensive access to these valuable building blocks. The method is employed on a variety of different pyridines and carboxylic acid alkyl donors, is operationally simple and scalable, and is applied to access known structures in a rapid and inexpensive fashion. Finally, this work points to an interesting strategic departure for the use of Minisci chemistry at the earliest possible stage (native pyridine) rather than current dogma that almost exclusively employs Minisci chemistry as a late-stage functionalization technique.

Site-selective direct C-H pyridylation of unactivated alkanes by triplet excited anthraquinone

Site-selective C-H functionalization in chemical feedstocks is a challenging and useful reaction in the broad field of chemical research. Here, we report a modular photochemical platform for the site-selective C-H pyridylation of unactivated hydrocarbons via the unique synergistic effects of triplet excited anthraquinone and an amidyl radical-based reverse hydrogen atom transfer (RHAT) agent. The selective pyridylation of tertiary and secondary C(sp3)-H bonds in abundant chemical feedstocks was achieved by employing various N-aminopyridinium salts in a highly selective fashion, thus providing a new catalytic system for the direct construction of high-value-added compounds under ambient reaction conditions. Moreover, this operationally simple protocol is applicable to a variety of linear-, branched-, and cyclo-alkanes and more complex molecules with high degrees of site selectivity under visible-light conditions, which provides rapid and straightforward access to versatile synthons for upgrading feedstocks under mild, metal-free reaction conditions.

Visible-Light-Driven C4-Selective Alkylation of Pyridinium Derivatives with Alkyl Bromides

Reported herein is a general strategy for the photochemical cross-coupling between N-amidopyridinium salts and various alkyl bromides under photocatalyst-free conditions, granting facile access to various C4-alkylated pyridines. This approach exploits the intriguing photochemical activity of electron donor-acceptor (EDA) complexes between N-amidopyridinium salts and bromide, which provides a photoactive handle capable of generating silyl radicals and driving the alkylation process. The robustness of this protocol was further demonstrated by the late-stage functionalization of complex compounds under mild and metal-free conditions.

A Practical Method for Continuous Production of sp3-Rich Compounds from (Hetero)Aryl Halides and Redox-Active Esters

A practically useful coupling reaction between aromatic halides and redox-active esters was realized by nickel catalysis through the use of a packed zinc bed column in continuous flow. Multiple reuse of the column showed a negligible decrease in efficiency, affording high space/time yields. A wide range of substrates, including a number of heteroaryl halides and polyfunctional materials were coupled in generally good yields. Longer-time and larger-scale experiments further demonstrates the robustness of the system.

Efficient Diastereoselective Three-Component Synthesis of Pipecolic Amides

An efficient Ugi-type three-component reaction (U-3CR) for the synthesis of pipecolic amides is reported. The U-3CR between electronically diverse isocyanides, carboxylic acids and 4-substituted Δ1-piperideines proceeds in a highly diastereoselective fashion. The Δ1-piperideines are obtained by NCS-mediated oxidation of the corresponding 4-substituted piperidines, which in turn are generated by an efficient two-step procedure involving the alkylation of 4-picoline and subsequent catalytic hydrogenation of the pyridine ring. We demonstrate the utility of this U-3CR, in combination with the convertible isocyanide 2-bromo-6-isocyanopyridine, in the synthesis of the anticoagulant argatroban.

Direct arylation of strong aliphatic C–H bonds

Despite the widespread success of transition-metal-catalysed cross-coupling methodologies, considerable limitations still exist in reactions at sp3-hybridized carbon atoms, with most approaches relying on prefunctionalized alkylmetal or bromide coupling partners1,2. Although the use of native functional groups (for example, carboxylic acids, alkenes and alcohols) has improved the overall efficiency of such transformations by expanding the range of potential feedstocks3–5, the direct functionalization of carbon–hydrogen (C–H) bonds—the most abundant moiety in organic molecules—represents a more ideal approach to molecular construction. In recent years, an impressive range of reactions that form C(sp3)–heteroatom bonds from strong C–H bonds has been reported6,7. Additionally, valuable technologies have been developed for the formation of carbon–carbon bonds from the corresponding C(sp3)–H bonds via substrate-directed transition-metal C–H insertion8, undirected C–H insertion by captodative rhodium carbenoid complexes9, or hydrogen atom transfer from weak, hydridic C–H bonds by electrophilic open-shell species10–14. Despite these advances, a mild and general platform for the coupling of strong, neutral C(sp3)–H bonds with aryl electrophiles has not been realized. Here we describe a protocol for the direct C(sp3) arylation of a diverse set of aliphatic, C–H bond-containing organic frameworks through the combination of light-driven, polyoxometalate-facilitated hydrogen atom transfer and nickel catalysis. This dual-catalytic manifold enables the generation of carbon-centred radicals from strong, neutral C–H bonds, which thereafter act as nucleophiles in nickel-mediated cross-coupling with aryl bromides to afford C(sp3)–C(sp2) cross-coupled products. This technology enables unprecedented, single-step access to a broad array of complex, medicinally relevant molecules directly from natural products and chemical feedstocks through functionalization at sites that are unreactive under traditional methods.

Harnessing Alkyl Amines as Electrophiles for Nickel-Catalyzed Cross Couplings via C-N Bond Activation

We developed a strategy to harness alkyl amines as alkylating agents via C-N bond activation. This Suzuki-Miyaura cross coupling of alkylpyridinium salts, readily formed from primary amines, is the first example of a metal-catalyzed cross coupling via C-N bond activation of an amine with an unactivated alkyl group. This reaction enjoys broad scope and functional group tolerance. Primary and secondary alkyl groups can be installed. Preliminary studies suggest a NiI/NiIII catalytic cycle.

Synthesis and utility of dihydropyridine boronic esters

When activated by an acylating agent, pyridine boronic esters react with organometallic reagents to form a dihydropyridine boronic ester. This intermediate allows access to a number of valuable substituted pyridine, dihydropyridine, and piperidine products.

Transition-metal-free BF3-mediated oxidative and non-oxidative cross-coupling of pyridines

We report a BF3-mediated direct alkynylation of pyridines at C(2) by using a variety of alkynyllithium reagents (oxidative cross-coupling). Moreover, we have developed a novel transition-metal-free cross-coupling method between alkylmagnesium reagents and 4-substituted pyridines, such as isonicotinonitrile and 4-chloropyridine, by employing BF3· OEt2 as a promoter. The combination of these methods enabled us to efficiently prepare a range of di-, tri-, and tetrasubstituted pyridines. Oxidative or non-oxidative - That is the question! Pyridines bearing a substituent at position 4 readily undergo a BF3-mediated oxidative coupling at position 2 with a wide range of alkynyllithium compounds. In contrast, 4-cyano- or 4-chloropyridines undergo a novel BF3-mediated cross-coupling at position 4 with alkylmagnesium reagents. The combination of the two transition-metal-free procedures allows the preparation of a broad range of pyridines.

Homodimeric bis-quaternary heterocyclic ammonium salts as potent acetyl- and butyrylcholinesterase inhibitors: A systematic investigation of the influence of linker and cationic heads over affinity and selectivity

A molecular library of quaternary ammonium salts (QASs), mainly composed of symmetrical bis-quaternary heterocyclic bromides exhibiting choline kinase (ChoK) inhibitory activity, were evaluated for their ability to inhibit acetyl- and butyrylcholinesterase (AChE and BChE, respectively). The molecular framework of QASs consisted of two positively charged heteroaromatic (pyridinium or quinolinium) or sterically hindered aliphatic (quinuclidinium) nitrogen rings kept at an appropriate distance by lipophilic rigid or semirigid linkers. Many homodimeric QASs showed AChE and BChE inhibitory potency in the nanomolar range along with a low enzymatic selectivity. Computational studies on AChE, BChE, and ChoK allowed identification of the key molecular determinants for high affinity and selectivity over either one of the three enzymes and guided the design of a hybrid bis-QAS (56) exhibiting the highest AChE affinity (IC50 = 15 nM) and selectivity over BChE and ChoK (SI = 50 and 562, respectively) and a promising pharmacological potential in myasthenia gravis and neuromuscular blockade.