- Generation and Alkylation of α-Carbamyl Radicals via Organic Photoredox Catalysis
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Strategies for the direct C-H functionalization of amines are valuable as these compounds comprise a number of pharmaceuticals, agrochemicals and natural products. This work describes a novel method for the C-H functionalization of carbamate-protected secondary amines via α-carbamyl radicals generated using photoredox catalysis. The use of the highly oxidizing, organic acridinium photoredox catalyst allows for direct oxidation of carbamate-protected amines with high redox potentials to give the corresponding carbamyl cation radical. Following deprotonation, the resultant open-shell species can be intercepted by a variety of Michael acceptors to give elaborate α-functionalized secondary amines. The reaction proceeds under mild conditions without the requirement of exogenous redox mediators or substrate prefunctionalization. Additionally, we were able to showcase the utility of this methodology through the enantioselective synthesis of the indolizidine alkaloid, (+)-monomorine I.
- McManus, Joshua B.,Onuska, Nicholas P. R.,Nicewicz, David A.
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- A short synthesis of argatroban: A potent selective thrombin inhibitor
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Argatroban was synthesized in seven steps from 4-methylpiperidine. The condensation of (±)-trans-benzyl 4-methylpipecolic acid ester with Nα-Boc-Nω-nitro-L-arginine led to two diastereomers that were separated. One of them is the precursor of argatroban.
- Cossy, Janine,Belotti, Damien
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- Single-step conversion of N-benzyl, N-trityl and N-diphenylmethyl amines to t-butyl carbamates using polymethylhydrosiloxane
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t-Butyl carbamates were obtained efficiently in high yields from the corresponding N-benzyl, N-trityl and N-diphenylmethyl precursors in a single-step reductive transformation employing polymethylhydrosiloxane and di-t-butyl dicarbonate under Pd(OH)2/C catalysis.
- Chandrasekhar,Babu, B. Nagendra,Reddy, Ch. Raji
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- Sustainable Route Toward N-Boc Amines: AuCl3/CuI-Catalyzed N-tert-butyloxycarbonylation of Amines at Room Temperature
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N-tert-butoxycarbonyl (N-Boc) amines are useful intermediates in synthetic/medicinal chemistry. Traditionally, they are prepared via an indirect phosgene route with poor atom economy. Herein, a step- and atom-economic synthesis of N-Boc amines from amines, t-butanol, and CO was reported at room temperature. Notably, this N-tert-butyloxycarbonylation procedure utilized ready-made substrates, commercially available AuCl3/CuI as catalysts, and O2 from air as the sole oxidant. This catalytic system provided unique selectivity for N-Boc amines in good yields. More significantly, gram-scale preparation of medicinally important N-Boc amine intermediates was successfully implement, which demonstrated a potential application prospect in industrial syntheses. Furthermore, this approach also showed good compatibility with tertiary and other useful alcohols. Investigations of the mechanisms revealed that gold catalyzed the reaction and copper acted as electron transfer mediator in the catalytic cycle.
- Cao, Yanwei,Huang, Yang,He, Lin
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- Deaminative Reductive Methylation of Alkylpyridinium Salts
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Methyl groups can imbue valuable properties in organic molecules, often leading to enhanced bioactivity. To enable efficient installation of methyl groups on simple building blocks and in late-stage functionalization, a nickel-catalyzed reductive coupling of secondary Katritzky alkylpyridinium salts with methyl iodide was developed. When coupled with formation of the pyridinium salt from an alkyl amine, this method allows amino groups to be readily transformed to methyl groups with broad functional group and heterocycle tolerance.
- Bercher, Olivia P.,Plunkett, Shane,Mortimer, Thomas E.,Watson, Mary P.
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supporting information
p. 7059 - 7063
(2021/09/18)
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- Catalytic Transfer Hydrogenation of Arenes and Heteroarenes
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Transfer hydrogenation reactions are of great interest to reduce diverse molecules under mild reaction conditions. To date, this type of reaction has only been successfully applied to alkenes, alkynes and polarized unsaturated compounds such as ketones, imines, pyridines, etc. The reduction of benzene derivatives by transfer hydrogenation has never been described, which is likely due to the high energy barrier required to dearomatize these compounds. In this context, we have developed a catalytic transfer hydrogenation reaction for the reduction of benzene derivatives and heteroarenes to form complex 3-dimensional scaffolds bearing various functional groups at room temperature without needing compressed hydrogen gas.
- Gelis, Coralie,Heusler, Arne,Nairoukh, Zackaria,Glorius, Frank
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supporting information
p. 14090 - 14094
(2020/10/19)
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- Amine-Responsive Disassembly of AuI–CuI Double Salts for Oxidative Carbonylation
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A sensitive amine-responsive disassembly of self-assembled AuI-CuI double salts was observed and its utilization for the synergistic catalysis was enlightened. Investigation of the disassembly of [Au(NHC)2][CuI2] revealed the contribution of Cu-assisted ligand exchange of N-heterocyclic carbene (NHC) by amine in [Au(NHC)2]+ and the capacity of [CuI2]? on the oxidative step. By integrating the implicative information coded in the responsive behavior and inherent catalytic functions of d10 metal complexes, a catalyst for the oxidative carbonylation of amines was developed. The advantages of this method were clearly reflected on mild reaction conditions and the significantly expanded scope (51 examples); both primary and steric secondary amines can be employed as substrates. The cooperative reactivity from Au and Cu centers, as an indispensable prerequisite for the excellent catalytic performance, was validated in the synthesis of (un)symmetric ureas and carbamates.
- Cao, Yanwei,Yang, Jian-Gong,Deng, Yi,Wang, Shengchun,Liu, Qi,Shen, Chaoren,Lu, Wei,Che, Chi-Ming,Chen, Yong,He, Lin
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supporting information
p. 2080 - 2084
(2019/12/24)
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- Stereoselective nucleophilic addition reactions to cyclic n-acyliminium ions using the indirect cation pool method: Elucidation of stereoselectivity by spectroscopic conformational analysis and dft calculations
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In this study, six-membered N-acyliminium ions were generated by the “indirect cation pool” method and reacted with several nucleophiles. These reactions afforded disubstituted piperidine derivatives with high diastereoselectivities and good to excellent
- Mitsudo, Koichi,Yamamoto, Junya,Akagi, Tomoya,Yamashita, Atsuhiro,Haisa, Masahiro,Yoshioka, Kazuki,Mandai, Hiroki,Ueoka, Koji,Hempel, Christian,Yoshida, Jun-ichi,Suga, Seiji
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supporting information
p. 1192 - 1202
(2018/06/04)
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- Nickel-Catalyzed Barton Decarboxylation and Giese Reactions: A Practical Take on Classic Transforms
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Two named reactions of fundamental importance and paramount utility in organic synthesis have been reinvestigated, the Barton decarboxylation and Giese radical conjugate addition. N-hydroxyphthalimide (NHPI) based redox-active esters were found to be conv
- Qin, Tian,Malins, Lara R.,Edwards, Jacob T.,Merchant, Rohan R.,Novak, Alexander J. E.,Zhong, Jacob Z.,Mills, Riley B.,Yan, Ming,Yuan, Changxia,Eastgate, Martin D.,Baran, Phil S.
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supporting information
p. 260 - 265
(2016/12/30)
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- HEMIASTERLIN DERIVATIVES AND USES THEREOF IN THE TREATMENT OF CANCER
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The present invention provides compounds having formula (I): and additionally provides methods for the synthesis thereof and methods for the use thereof in the treatment of cancer, wherein R 1 -R 7 , X 1 , X 2 , R, Q, and n are as defined herein.
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Paragraph 0131; 0132
(2016/08/17)
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- ANTICANCER AGENT
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An anticancer agent comprising a compound represented by the formula (I) [R1 represents hydrogen atom, hydroxyl group, a C1-6alkoxy group and the like; R2 and R3 represents hydrogen atom, a halogen atom, a C1-6alkyl group and the like; R4 represents hydrogen atom, a C1-6alkyl group, a C1-6alkylsulfonyl group and the like; R5 represents hydrogen atom or a substituent; .... represents a single bond or a double bond; R6 and R7 represents hydrogen atom, a C1-6alkyl group and the like; R8 represents hydrogen atom, a C1-6alkyl group and the like; A represents -O-, -S-, or - CH2-; D represents -C= or -N=; X represents methylene group, -O-, or -CO-; Q represents -N= or -C(R8)=; and Y represents a heterocyclic group or amino group], which shows a superior inhibitory activity against pim-1 kinase.
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Paragraph 0533
(2013/03/26)
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- Iron(III)triflate as a highly efficient, recyclable and green catalyst for the N-Boc protection of amines
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Iron (III) triflate was used as an efficient catalyst for N-t-butoxycarbonylation of amines with di-t-butyl dicarbonate under solvent-free conditions at room temperature. Various aliphatic, aromatic, heterocyclic amines and aminols were protected as their corresponding mono-carbamates in excellent yields and short reaction times. Only two of the 23 monocarbamates were new. No competitive side reactions such as isocyanate, urea, nor N,N-di-Boc formation were observed. The reported method is mild and has the advantages of low cost, chemoselectivity and, because no solvent is used and the catalyst can be recycled, it is classifiable as a green procedure.
- Feng, Chengliang,Chu, Ningning,Zhang, Shuguang,Cai, Jin,Chen, Junqing,Hu, Huayou,Ji, Min
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p. 757 - 760
(2014/01/23)
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- Bromodimethyl sulfonium bromide mediated rapid and facile protection of amines
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A new clean protocol for protection of aryl and aliphatic amines with t-butoxycarbonyl (t-BOC) and benzyloxycarbonyl (Cbz) catalyzed by simple (bromodimethyl) sulfonium bromide has been developed. Rapid protection of amines in excellent yields in totally solvent-free conditions has been achieved. Copyright
- Shailaja,Manjula,Vittal Rao
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experimental part
p. 2073 - 2080
(2011/07/31)
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- From natural products to achiral drug prototypes: Potent thrombin inhibitors based on P2/P3 dihydropyrid-2-one core motifs
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A series of dihydropyrid-2-ones was synthesized and tested for inhibitory activity against serine protease enzymes. Moderate to low nanomolar inhibitory activities were obtained against thrombin and excellent selectivity against trypsin was observed.
- Hanessian, Stephen,Therrien, Eric,Zhang, Jianbin,Otterlo, Willem van,Xue, Yafeng,Gustafsson, David,Nilsson, Ingemar,Fjellstroem, Ola
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scheme or table
p. 5429 - 5432
(2010/05/19)
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- A two-step, formal [4 + 2] approach toward piperidin-4-ones via au catalysis
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(Chemical Equation Presented) An efficient, formal [4 + 2] synthesis of synthetically valuable piperidin-4-ones from secondary amines in two steps has been achieved via a key gold catalysis without the purification of tertiary amine intermediates. This reaction is selective toward the less-substituted alkyl group and shows moderate to excellent diastereoselectivities. Its synthetic potential in alkaloid synthesis is demonstratedin a highly diastereoselective synthesis of (±)-cermizine C.
- Cui, Li,Peng, Yu,Zhang, Liming
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supporting information; experimental part
p. 8394 - 8395
(2009/10/23)
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- DIPEPTIDYL PEPTIDASE-IV INHIBITING COMPOUNDS, METHODS OF PREPARING THE SAME, AND PHARMACEUTICAL COMPOSITIONS CONTAINING THE SAME AS AN ACTIVE AGENT
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The present invention relates to novel compounds exhibiting good inhibitory activity versus Dipeptidyl Peptidase-IV(DPP-IV), methods of preparing the same and pharmaceutical compositions containing the same as an active agent.
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Page/Page column 31
(2010/11/24)
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- Molecular iodine-catalyzed facile procedure for N-Boc protection of amines
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An efficient and practical protocol for the protection of various structurally and electronically divergent aryl and aliphatic amines using (Boc)2O in the presence of a catalytic amount of molecular iodine (10 mol%) under solvent-free conditions at ambient temperature is presented.
- Varala, Ravi,Nuvula, Sreelatha,Adapa, Srinivas R.
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p. 8283 - 8286
(2007/10/03)
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- THROMBIN INHIBITING 2-OXO-1, 2, 5, 6-TETRAHYDROPYRIDINE DERIVATIVES
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There is provided a compound of formula (I) wherein R1, R2a, R2b, R3a, R3b, R4, R5a, R5b, R6 to R8, A and G have meanings given in the description, which compounds are useful as, or are useful as prodrugs of, competitive inhibitors of trypsin-like proteases, such as thrombin, and thus, in particular, in the treatment of conditions where inhibition of thrombin is beneficial (e.g. conditions, such as thrombo-embolisms, where inhibition of thrombin is required or desired, and/or conditions where anticoagulant therapy is indicated).
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Page/Page column 52-53
(2010/11/25)
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- NEW 5,6-DIHYDROPYRIN-2-ONE COMPOUNDS USEFUL AS INHIBITORS OF THROMBIN
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There is provided a compound of formula (I) wherein R1, R2a, R2b, R3a, R3b, R4, R5, R6, A, G and L have meanings given in the description, which compounds are useful a
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Page/Page column 88
(2010/02/12)
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