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Concise approach to γ-(het)aryl- and γ-alkenyl-γ-aminobutyric acids. Synthesis of vigabatrin. Org Biomol Chem 2024; 22:1027-1033. [PMID: 38193622 DOI: 10.1039/d3ob01769a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2024]
Abstract
γ-Aminobutyric acid (GABA) and GABA derivatives have attracted increased attention over the years in the fields of medicinal chemistry and chemical biology due to their interesting biological properties and synthetic relevance. Here, we report a short synthetic route to γ-(het)aryl- and γ-alkenyl-γ-aminobutyric acids, including the antiepileptic drug vigabatrin, from readily available donor-acceptor cyclopropanes and ammonia or methylamine. This protocol includes a facile synthesis of 2-oxopyrrolidine-3-carboxamides and their acid hydrolysis to γ-aryl- or γ-alkenyl-substituted GABAs, which can serve as perspective building blocks for the synthesis of various GABA-based N-heterocycles and bioactive compounds.
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2
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Donor-Acceptor Cyclopropane Ring Expansion to 1,2-Dihydronaphthalenes. Access to Bridged Seven-Membered Lactones. Org Lett 2023; 25:7963-7967. [PMID: 37916763 DOI: 10.1021/acs.orglett.3c02846] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2023]
Abstract
A Lewis-acid-promoted domino ring-opening cyclization of readily available donor-acceptor cyclopropanes with a preinstalled electrophilic center, embedded in a donor group, to functionalized 1,2-dihydronaphthalenes is reported herein. The obtained compounds are transformed to pharmacologically attractive bridged tricyclic esters in a diastereospecific manner.
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3
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A simple method for the synthesis of isoindoline derivatives. Chem Heterocycl Compd (N Y) 2023. [DOI: 10.1007/s10593-023-03162-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/29/2023]
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4
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Synthesis of 1,5-Substituted Pyrrolidin-2-ones from Donor-Acceptor Cyclopropanes and Anilines/Benzylamines. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27238468. [PMID: 36500574 PMCID: PMC9735934 DOI: 10.3390/molecules27238468] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/29/2022] [Revised: 11/16/2022] [Accepted: 11/23/2022] [Indexed: 12/12/2022]
Abstract
We developed a straightforward synthetic route to pharmacologically important 1,5-substituted pyrrolidin-2-ones from donor-acceptor cyclopropanes bearing an ester group as one of the acceptor substituents. This method includes a Lewis acid-catalyzed opening of the donor-acceptor cyclopropane with primary amines (anilines, benzylamines, etc.) to γ-amino esters, followed by in situ lactamization and dealkoxycarbonylation. The reaction has a broad scope of applicability; a variety of substituted anilines, benzylamines, and other primary amines as well as a wide range of donor-acceptor cyclopropanes bearing (hetero)aromatic or alkenyl donor groups and various acceptor substituents can be involved in this transformation. In this process, donor-acceptor cyclopropanes react as 1,4-C,C-dielectrophiles, and amines react as 1,1-dinucleophiles. The resulting di- and trisubstituted pyrrolidin-2-ones can be also used in subsequent chemistry to obtain various nitrogen-containing polycyclic compounds of interest to medicinal chemistry and pharmacology, such as benz[g]indolizidine derivatives.
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5
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Ambident reactivity of 5-aminopyrazoles towards donor-acceptor cyclopropanes. Org Biomol Chem 2022; 20:7795-7802. [PMID: 36148530 DOI: 10.1039/d2ob01490d] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Lewis acid-catalysed reactions of donor-acceptor cyclopropanes with 1,3-disubstituted 5-aminopyrazoles were investigated. Under catalysis with gallium(III) chloride, products of the three-membered ring opening via a nucleophilic attack of the exocyclic amino group were obtained in a chemoselective manner. Oppositely, in the presence of scandium(III) triflate, products of either N-alkylation or C(4)-alkylation, or a mixture of both were formed. The products of the C(4) alkylation were transformed in one step into tetrahydropyrazolo[3,4-b]azepines that are attractive for medicinal chemistry and pharmacology.
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6
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Extended Corey–Chaykovsky reactions: transformation of 2-hydroxychalcones to benzannulated 2,8-dioxabicyclo[3.2.1]octanes and 2,3-dihydrobenzofurans. Org Chem Front 2022. [DOI: 10.1039/d1qo01646f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
We report the divergent synthesis of benzannulated 2,8-dioxabicyclo[3.2.1]octanes and 2,3-dihydrobenzofurans using the concept of extended Corey–Chaykovsky reactions.
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7
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Expanding Stereoelectronic Limits of endo- tet Cyclizations: Synthesis of Benz[ b]azepines from Donor-Acceptor Cyclopropanes. J Am Chem Soc 2021; 143:13952-13961. [PMID: 34406759 DOI: 10.1021/jacs.1c07088] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The importance of intramolecular constraints in cyclic transition-state geometries is especially pronounced in n-endo-tet cyclizations, where the usual backside approach of a nucleophile to the breaking bond is impossible for the rings containing less than eight atoms. Herein, we expand the limits of endo-tet cyclizations and show that donor-acceptor cyclopropanes can provide a seven-membered ring via a genuine 6-endo-tet process. Substrates containing a N-alkyl-N-arylcarbamoyl moiety as an acceptor group undergo Lewis acid-induced cyclization to form tetrahydrobenz[b]azepin-2-ones in high yields. The reaction proceeds with the inversion of the configuration at the electrophilic carbon. In this process, a formally six-membered transition state yields a seven-membered ring as the pre-existing cycle is merged into the forming ring. The stereochemistry of the products can be controlled by the reaction time and by the nature of Lewis acid, opening access to both diastereomers by tuning of the reaction conditions.
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8
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Donor-Acceptor Cyclopropane Ring Opening with 6-Amino-1,3-dimethyluracil and Its Use in Pyrimido[4,5- b]azepines Synthesis. J Org Chem 2021; 86:12300-12308. [PMID: 34382810 DOI: 10.1021/acs.joc.1c01064] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
A scandium trifluoromethanesulfonate-catalyzed reaction of donor-acceptor cyclopropanes with 6-amino-1,3-dimethyluracil was found to proceed as three-membered ring opening via nucleophilic attack of the C(5) atom of an ambident nucleophile serving as an enamine equivalent. It was shown that, under basic conditions, the obtained products underwent cyclization to 6,7-dihydro-1H-pyrimido[4,5-b]azepine-2,4,8-triones, an interesting subclass of nucleobase analogues.
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9
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Protic Ionic Liquid as Reagent, Catalyst, and Solvent: 1-Methylimidazolium Thiocyanate. Angew Chem Int Ed Engl 2021; 60:7927-7934. [PMID: 33433034 PMCID: PMC8048580 DOI: 10.1002/anie.202016593] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Indexed: 02/06/2023]
Abstract
We propose a new concept of the triple role of protic ionic liquids with nucleophilic anions: a) a regenerable solvent, b) a Brønsted acid inducing diverse transformations via general acid catalysis, and c) a source of a nucleophile. The efficiency of this strategy was demonstrated using thiocyanate-based protic ionic liquids for the ring-opening of donor-acceptor cyclopropanes. A wide variety of activated cyclopropanes were found to react with 1-methylimidazolium thiocyanate under mild metal-free conditions via unusual nitrogen attack of the ambident thiocyanate ion on the electrophilic center of the three-membered ring affording pyrrolidine-2-thiones bearing donor and acceptor substituents at the C(5) and C(3) atoms, respectively, in a single time-efficient step. The ability of 1-methylimidazolium thiocyanate to serve as a triplex reagent was exemplarily illustrated by (4+2)-annulation with 1-acyl-2-(2-hydroxyphenyl)cyclopropane, epoxide ring-opening and other organic transformations.
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10
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Protic Ionic Liquid as Reagent, Catalyst, and Solvent: 1‐Methylimidazolium Thiocyanate. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202016593] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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11
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Synthesis of (Het)aryl 2-(2-hydroxyaryl)cyclopropyl Ketones. Molecules 2020; 25:molecules25235748. [PMID: 33291488 PMCID: PMC7729819 DOI: 10.3390/molecules25235748] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2020] [Revised: 12/02/2020] [Accepted: 12/04/2020] [Indexed: 11/16/2022] Open
Abstract
A simple general method for the synthesis of 1-acyl-2-(ortho-hydroxyaryl)cyclopropanes, which belong to the donor–acceptor cyclopropane family, has been developed. This method, based on the Corey–Chaykovsky cyclopropanation of 2-hydroxychalcones, allows for the preparation of a large diversity of hydroxy-substituted cyclopropanes, which can serve as promising building blocks for the synthesis of various bioactive compounds.
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12
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13
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A simple synthesis of 2-{2-[(arylmethylidene)amino]-indazol-3-yl}malonate esters. Chem Heterocycl Compd (N Y) 2020. [DOI: 10.1007/s10593-020-02699-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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14
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Porous polylactide prepared by the delocalized crazing as a template for nanocomposite materials. MENDELEEV COMMUNICATIONS 2020. [DOI: 10.1016/j.mencom.2020.03.013] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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15
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Ring Opening of Donor–Acceptor Cyclopropanes with Cyanide Ion and Its Surrogates. J Org Chem 2019; 85:1146-1157. [DOI: 10.1021/acs.joc.9b03098] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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16
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Donor-Acceptor Cyclopropanes in the Synthesis of Carbocycles. CHEM REC 2019; 19:2189-2208. [PMID: 30707497 DOI: 10.1002/tcr.201800166] [Citation(s) in RCA: 72] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Accepted: 01/07/2019] [Indexed: 01/24/2023]
Abstract
Donor-acceptor cyclopropanes not only participate in a broad range of ring openings with nucleophiles, electrophiles, radical and red-ox agents, but also are excellent substrates for various (3+n)-cycloaddition and (3+n)-annulation processes. Moreover, under treatment with Lewis acid donor-acceptor cyclopropanes can produce new ring systems via isomerization or cyclodimerization. Authors' contribution to the synthesis of diverse carbocycles from donor-acceptor cyclopropanes is summarized in this account.
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Abstract
Vascular leiomyosarcoma (LMS) is an extremely rare disease. Venous lesion is approximately 5 times more common than arterial. LMS is usually found in retroperitoneal veins and in inferior vena cava. Lesion of the splenic vein is extremely rare. A 52-year-old woman with recurrent abdominal pain is reported in the article. Abdominal contrast-enhanced CT revealed a 6 cm tumor of the pancreatic tail. The patient underwent laparoscopic distal pancreatectomy with splenectomy en bloc. Histological and immunohistochemical studies revealed LMS originating from the smooth muscles of the splenic vein. Surgery was followed by adjuvant chemotherapy. There was no local recurrence in 1 year after surgery. In this article, we analyze the available information on leiomyosarcoma of the splenic vein.
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18
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Synthesis of 1-Substituted Pyrazolines by Reaction of Donor-Acceptor Cyclopropanes with 1,5-Diazabicyclo[3.1.0]hexanes. European J Org Chem 2019. [DOI: 10.1002/ejoc.201900579] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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19
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Investigating 1,2,3,4,5,6-hexahydroazepino[4,3-b]indole as scaffold of butyrylcholinesterase-selective inhibitors with additional neuroprotective activities for Alzheimer's disease. Eur J Med Chem 2019; 177:414-424. [PMID: 31158754 DOI: 10.1016/j.ejmech.2019.05.062] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2019] [Revised: 05/13/2019] [Accepted: 05/23/2019] [Indexed: 12/19/2022]
Abstract
Due to the role of butyrylcholinesterase (BChE) in acetylcholine hydrolysis in the late stages of the Alzheimer's disease (AD), inhibitors of butyrylcholinesterase (BChE) have been recently envisaged, besides acetylcholinesterase (AChE) inhibitors, as candidates for treating mild-to-moderate AD. Herein, synthesis and AChE/BChE inhibition activity of some twenty derivatives of 1,2,3,4,5,6-hexahydroazepino[4,3-b]indole (HHAI) is reported. Most of the newly synthesized HHAI derivatives achieved the inhibition of both ChE isoforms with IC50s in the micromolar range, with a structure-dependent selectivity toward BChE. Apparently, molecular volume and lipophilicity do increase selectivity toward BChE, and indeed the N2-(4-phenylbutyl) HHAI derivative 15d, which behaves as a mixed-type inhibitor, resulted the most potent (IC50 0.17 μM) and selective (>100-fold) inhibitor toward either horse serum and human BChE. Moreover, 15d inhibited in vitro self-induced aggregation of neurotoxic amyloid-β (Aβ) peptide and displayed neuroprotective effects in neuroblastoma SH-SY5Y cell line, significantly recovering (P < 0.001) cell viability when impaired by Aβ1-42 and hydrogen peroxide insults. Overall, this study highlighted HHAI as useful and versatile scaffold for developing new small molecules targeting some enzymes and biochemical pathways involved in the pathogenesis of AD.
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20
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Convenient Synthesis of Functionalized Cyclopropa[ c]coumarin-1a-carboxylates. Molecules 2018; 24:molecules24010057. [PMID: 30586901 PMCID: PMC6337311 DOI: 10.3390/molecules24010057] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2018] [Revised: 12/15/2018] [Accepted: 12/22/2018] [Indexed: 01/08/2023] Open
Abstract
A simple method has been developed for the synthesis of cyclopropa[c]coumarins, which belong to the donor-acceptor cyclopropane family and, therefore, are promising substrates for the preparation of chromene-based fine chemicals. The method, based on the acetic acid-induced intramolecular transesterification of 2-arylcyclopropane-1,1-dicarboxylates, was found to be efficient for substrates containing hydroxy group directly attached to the aromatic ring.
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21
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Expanding the Reactivity of Donor-Acceptor Cyclopropanes: Synthesis of Benzannulated Five-Membered Heterocycles via Intramolecular Attack of a Pendant Nucleophilic Group. Org Lett 2018; 20:7947-7952. [PMID: 30517005 DOI: 10.1021/acs.orglett.8b03491] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Lewis-acid-induced domino transformations of donor-acceptor cyclopropanes, possessing a nucleophilic center embedded in a donor group, into functionalized 2,3-dihydrobenzo[ b]furans and 2,3-dihydrobenzo[ b]thiophenes are reported herein. An unusual switch of the electrophilic center in the three-membered ring, from the atom bearing a donor substituent to an unsubstituted carbon atom, was achieved by a judicious choice of Lewis acid, which induces the isomerization of a cyclopropane to an electrophilic alkene, and the length of linker, connecting a nucleophilic moiety and the small ring.
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22
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23
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(3+3)-Annulation of Donor-Acceptor Cyclopropanes with Diaziridines. Angew Chem Int Ed Engl 2018; 57:10338-10342. [PMID: 29936708 DOI: 10.1002/anie.201805258] [Citation(s) in RCA: 86] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2018] [Revised: 06/10/2018] [Indexed: 12/11/2022]
Abstract
The first example of (3+3)-annulation of two different three-membered rings is reported herein. Donor-acceptor cyclopropanes in reaction with diaziridines were found to afford perhydropyridazine derivatives in high yields and diastereoselectivity under mild Lewis acid catalysis. The disclosed reaction is applicable for the broad substrate scope and exhibits an excellent functional group tolerance.
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24
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P62Pathway analysis of RNA-sequencing of various stages of myodifferentiaion identifies conditions favoring type i and type II fibers, and highlights increased efficiency of combined differentiation. Cardiovasc Res 2018. [DOI: 10.1093/cvr/cvy060.027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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25
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Methods for the synthesis of donor-acceptor cyclopropanes. RUSSIAN CHEMICAL REVIEWS 2018. [DOI: 10.1070/rcr4787] [Citation(s) in RCA: 66] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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26
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Abstract P3-01-18: Determining the need for axillar lymph node dissection based on pre-neoadjuvant chemotherapy sentinel lymph node biopsy results. Cancer Res 2018. [DOI: 10.1158/1538-7445.sabcs17-p3-01-18] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
An open-label single institution study of sentinel lymph node biopsy prior to neoadjuvant chemotherapy is conducted in the N.N. Petrov research institute of oncology. So far 30 patients with locally advanced breast carcinoma (T2-4N0) were included. Mammography, breast US and SPECT are performed prior to hospitalization so as core biopsy with subsequent IHC staining to determine the levels of ER, PR, KI67 and HER2. Sentinel lymph node biopsy with the use of radiocompound is performed prior to the first cycle of neoadjuvant chemotherapy. Patients receive 4 to 6 cycles with response evaluation after cycles 2, 4 and 6 (same evaluations as at the baseline). Axillary lymph node dissection is later performed along with the definitive surgery of the primary.
Interim analysis showed: 3 of 30 patients with cN0 were node positive after sentinel lymph node biopsy, 27 were node-negative (sn)pN0. All patients with (sn)pN0 completed neoadjuvant chemotherapy with clinical response. No cases of upfront progression were detected. All patients (sn)pN0 underwent axillary dissection upon completion of the neoadjuvant therapy. No cases of nodal involvement were detected (ypN0). All of the patients considered node-positive after sentinel biopsy also underwent lymph node dissection after completion of the neoadjuvant therapy. 2 of them were pN1 and one was pN2.
Conclusion: sentinel lymph node biopsy in cN0 patients prior to neoadjuvant chemotherapy allows to determine a category of patients ((sn)pN0) in whom axillary dissection can be avoided, provided they remain clinically node-negative at the time of definitive surgery.
Citation Format: Semiglazov VF, Krivorotko PV, Zhiltsova EK, Dashayan GA, Zernov KU, Bessonov AA, Trufanova ES, Tabagua TT, Ivanova OA, Kanaev SV, Novikov SN, Krzivickiyi PI, Brayanceva ZV, Komayachov AV, Nikolaev KS, Gigolaeva LP. Determining the need for axillar lymph node dissection based on pre-neoadjuvant chemotherapy sentinel lymph node biopsy results [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P3-01-18.
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Convenient approach to polyoxygenated dibenzo[c,e]pyrrolo[1,2-a]azepines from donor–acceptor cyclopropanes. Org Chem Front 2018. [DOI: 10.1039/c8qo00742j] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
A convenient approach to polyoxygenated tetrahydrodibenzo[c,e]pyrrolo[1,2-a]azepines from the donor–acceptor cyclopropanes has been developed.
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28
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Abstract
We report a mild Lewis acid induced isomerization of donor-acceptor cyclopropanes, containing an alkenyl moiety and diverse electron-withdrawing group(s) at the adjacent positions, into substituted cyclopentenes. We have found that 1,1,2-trisubstituted cyclopent-3-enes were exclusively obtained in yield of 51-99% when cyclopropanes with a 2-substituted alkenyl group as a donor underwent isomerization. For cyclopropanes bearing a trisubstituted alkenyl group either the corresponding cyclopent-3-enes or isomeric cyclopent-2-enes having two acceptor groups at the C(1) atom were formed, with the reaction selectivity being determined by the applied Lewis acid. We have shown that the reactivity of the donor-acceptor cyclopropane increases with the increase of the electron-donating character of (hetero)aromatic group attached to the alkenyl moiety. The synthetic utility of the developed methodology was also demonstrated through the synthesis of polysubstituted cyclopentane and piperidine derivatives.
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29
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Cosmic radiation monitoring at low-Earth orbit by means of thermoluminescence and plastic nuclear track detectors. RADIAT MEAS 2017. [DOI: 10.1016/j.radmeas.2016.12.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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30
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Cold Crystallization of Glassy Polylactide during Solvent Crazing. ACS APPLIED MATERIALS & INTERFACES 2017; 9:34325-34336. [PMID: 28895718 DOI: 10.1021/acsami.7b09666] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Uniaxial tension accompanied by the orientation and crystallization of polymer chains is one of the powerful methods for the improvement of mechanical properties. Crystallization of amorphous isotropic polylactide (PLA) at room temperature is studied for the first time during the drawing of films in the presence of liquid adsorption-active media (ethanol, water-ethanol mixtures, and n-heptane) by the solvent crazing mechanism. The crystalline structure arises only under simultaneous actions of a liquid medium and a tensile stress and does not depend on the nature of the environment. The degree of polymer crystallinity increases nearly linearly with the growth in the fraction of the fibrillar material and reaches a maximum value of 42-45%. It has been stated that polymer crystallization happens in crazes involving nanofibrils with a diameter of about 10-20 nm without affecting the bulk polymer parts. Wide-angle X-ray scattering has been used to confirm that the crazing-induced crystallization is accompanied by the formation of the α'-crystalline phase with crystallite sizes (X-ray coherent scattering region) of 3-5 nm, depending on the nature of the liquid medium. After stretching in liquid media to a high tensile strain, the strength of a PLA film has increased to 200 MPa.
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31
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Domino Staudinger/aza-Wittig/Mannich Reaction: An Approach to Diversity of Di- and Tetrahydropyrrole Scaffolds. Chemistry 2016; 22:17967-17971. [PMID: 27685760 DOI: 10.1002/chem.201604056] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Indexed: 11/10/2022]
Abstract
A highly efficient and selective domino reaction producing valuable di- and tetrahydropyrrole-based skeletons from azidoethyl-substituted CH-acids and (thio)carbonyl compounds has been developed. By involving the additional functional groups in starting compounds into the domino reaction or postmodification of the primary reaction products, the simple construction of the pharmaceutically relevant three- and polycyclic azaheterocyclic scaffolds was demonstrated.
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32
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A Straightforward Approach to Tetrahydroindolo[3,2- b
]carbazoles and 1-Indolyltetrahydrocarbazoles through [3+3] Cyclodimerization of Indole-Derived Cyclopropanes. Chemistry 2016. [DOI: 10.1002/chem.201504890] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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33
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Cover Picture: A Straightforward Approach to Tetrahydroindolo[3,2- b
]carbazoles and 1-Indolyltetrahydrocarbazoles through [3+3] Cyclodimerization of Indole-Derived Cyclopropanes (Chem. Eur. J. 4/2016). Chemistry 2016. [DOI: 10.1002/chem.201504861] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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34
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Concise approach to pyrrolizino[1,2-b]indoles from indole-derived donor–acceptor cyclopropanes. RSC Adv 2016. [DOI: 10.1039/c6ra11233a] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
A direct approach to previously unexplored pyrrolizidino[1,2-b]indole system from indole-derived donor–acceptor cyclopropanes based on a sequence of three synthetic steps was developed.
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35
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Simple assembly of polysubstituted pyrazoles and isoxazoles via ring closure–ring opening domino reaction of 3-acyl-4,5-dihydrofurans with hydrazines and hydroxylamine. Org Biomol Chem 2016; 14:2905-15. [DOI: 10.1039/c5ob02596f] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A general approach to 2-(pyrazolyl-/isoxazolyl-)ethanols based on the Brønsted acid-initiated reaction of 3-acyl-4,5-dihydrofurans with hydrazines or hydroxylamine was developed.
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Formal [3 + 2]-Cycloaddition of Donor–Acceptor Cyclopropanes to 1,3-Dienes: Cyclopentane Assembly. J Org Chem 2015; 80:12212-23. [DOI: 10.1021/acs.joc.5b02146] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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Cover Picture: Ring Opening of Donor-Acceptor Cyclopropanes with the Azide Ion: A Tool for Construction of N-Heterocycles (Chem. Eur. J. 13/2015). Chemistry 2015. [DOI: 10.1002/chem.201590047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Ring opening of donor-acceptor cyclopropanes with the azide ion: a tool for construction of N-heterocycles. Chemistry 2015; 21:4861. [PMID: 25712782 DOI: 10.1002/chem.201500456] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Invited for the cover of this issue is the group of Ekaterina M. Budynina and Igor V. Trushkov at Lomonosov Moscow State University. The image depicts the diversity of synthetic outcomes that can be achieved by using the ring-opening of donor-acceptor cyclopropanes with the azide ion as a triggering reaction. Read the full text of the article at 10.1002/chem.201405551.
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Lewis and Brønsted Acid Induced (3 + 2)-Annulation of Donor–Acceptor Cyclopropanes to Alkynes: Indene Assembly. Org Lett 2015; 17:770-3. [DOI: 10.1021/ol5037562] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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40
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Overview of the Liulin type instruments for space radiation measurement and their scientific results. LIFE SCIENCES IN SPACE RESEARCH 2015; 4:92-114. [PMID: 26177624 DOI: 10.1016/j.lssr.2015.01.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2014] [Revised: 01/15/2015] [Accepted: 01/26/2015] [Indexed: 05/24/2023]
Abstract
Ionizing radiation is recognized to be one of the main health concerns for humans in the space radiation environment. Estimation of space radiation effects on health requires the accurate knowledge of the accumulated absorbed dose, which depends on the global space radiation distribution, solar cycle and local shielding generated by the 3D mass distribution of the space vehicle. This paper presents an overview of the spectrometer-dosimeters of the Liulin type, which were developed in the late 1980s and have been in use since then. Two major measurement systems have been developed by our team. The first one is based on one silicon detector and is known as a Liulin-type deposited energy spectrometer (DES) (Dachev et al., 2002, 2003), while the second one is a dosimetric telescope (DT) with two or three silicon detectors. The Liulin-type instruments were calibrated using a number of radioactive sources and particle accelerators. The main results of the calibrations are presented in the paper. In the last section of the paper some of the most significant scientific results obtained in space and on aircraft, balloon and rocket flights since 1989 are presented.
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[PHOTODYNAMIC THERAPY FOR INTRADERMAL METASTASES OF BREAST CANCER USING THE MATRIX LIGHT-EMITTING DIODES APPARATUS LATUS]. VOPROSY ONKOLOGII 2015; 61:430-434. [PMID: 26242157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
There are presented results of photodynamic therapy (PDT) for patients with chemo- and radioresistant intradermal metastases of breast cancer using the matrix light-emitting diodes apparatus. To all patients prior to irradiation there was performed fluorescence diagnostics to assess the accumulation of the photosensitizer of chlorine series and photobleaching during PDT. The size of the irradiation area was 400 sm, the total dose of irradiation was 250J/cm2. PDT was accompanied by mild pain, which was stopped by administration of non-narcotic analgesics. Complete regression of intradermal lesions was registered in 2 of 4 cases, partial response was observed in 1 patient and the progression of the process in 1 case.
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[AUTOLOGOUS TRANSPLANTATION OF ADIPOSE TISSUE IN RECONSTRUCTIVE AND PLASTIC SURGERY. NEW POSSIBILITIES OF "OLD" MATERIAL]. VOPROSY ONKOLOGII 2015; 61:460-466. [PMID: 26242162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The work is devoted to the methods of application of own adipose tissue as a plastic material and presents the summary of the currently known data on the use of transplantation of adipose tissue in order to correct various defects of the body in plastic and reconstructive surgery. There are analyzed theoretical basis for the use of adipose tissue, provided the methods of administration depending on the area of the use, the severity of the defect and its localization. Data on new methods of the use of adipose tissue and own observations are presented. As an example of the effective use there is provided a detailed analysis of the use of adipose tissue transplantation in breast cancer patients who have different area defects after reconstructive surgery.
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Reaction of Corey Ylide with α,β-Unsaturated Ketones: Tuning of Chemoselectivity toward Dihydrofuran Synthesis. Org Lett 2014; 16:2830-3. [DOI: 10.1021/ol500877c] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
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44
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Duality of Donor-Acceptor Cyclopropane Reactivity as a Three-Carbon Component in Five-Membered Ring Construction: [3+2] Annulation Versus [3+2] Cycloaddition. Chemistry 2013; 19:6586-90. [DOI: 10.1002/chem.201300731] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2013] [Indexed: 12/21/2022]
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45
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[The use of factor analysis in determining the dietary patterns in the population]. GIGIENA I SANITARIIA 2013:45-48. [PMID: 24003699] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The possibilities of using one of the methods of multivariate statistics, factor analysis, in the study of the frequency of consumption of food categories for the population are considered. Comparison of the results with the results of other statistical methods (cluster and variance analysis) showed the adequacy of factor analysis in the study purposes.
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A bioinspired route to indanes and cyclopentannulated hetarenes via (3+2)-cyclodimerization of donor–acceptor cyclopropanes. Chem Commun (Camb) 2013; 49:11482-4. [DOI: 10.1039/c3cc44475a] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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47
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[Whether to apply the standard treatment for breast cancer in older patients: arguments for and against]. ADVANCES IN GERONTOLOGY = USPEKHI GERONTOLOGII 2013; 26:469-471. [PMID: 24640695] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Data results of treatment of elderly breast cancer patients in different medical centers are provided, cohort up to 1922 patients. Better survival indicators are recorded within this category when using standard treatment plans (the same as for main category of patients). However it has been noticed that in most cases the patients' age (70-80 years) was considered a barrier to prescription the adequate treatment; 54-98% of patients do not receive standard treatment.
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48
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[Work intensity and arterial hypertension]. MEDITSINA TRUDA I PROMYSHLENNAIA EKOLOGIIA 2012:1-6. [PMID: 22545456] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The authors presented dependence of arterial hypertension on work intensity, exemplified by two occupational groups--teachers and electricians, and demonstrated modifying influence of occupation on prevalence of traditional cardiovascular risk factors.
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Recent advances in ring-forming reactions of donor–acceptor cyclopropanes. MENDELEEV COMMUNICATIONS 2011. [DOI: 10.1016/j.mencom.2011.11.001] [Citation(s) in RCA: 205] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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50
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(3 + 3)-Cyclodimerization of Donor–Acceptor Cyclopropanes. Three Routes to Six-Membered Rings. J Org Chem 2011; 76:8852-68. [DOI: 10.1021/jo201612w] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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