- A Bifunctional B,N-Based Asymmetric Catalytic Nitrostyrene-Michael Addition Acting through a 10-Membered Ring Cyclic Transition State
-
The B,N-bifunctional catalyst homoboroproline has been applied to a catalytic asymmetric nitroalkene-Michael addition to β-nitrostyrene analogues, showing broad substrate tolerance, high conversions and moderate to good asymmetric induction. The ability o
- Du, Yihao,Erdem, Safiye S.,Sari, Ozlem,Whiting, Andrew
-
-
- Staudinger/aza-Wittig reaction to access Nβ-protected amino alkyl isothiocyanates
-
A unified approach to access Nβ-protected amino alkyl isothiocyanates using Nβ-protected amino alkyl azides through a general strategy of Staudinger/aza-Wittig reaction is described. The type of protocol used to access isothiocyanates depends on the availability of precursors and also, especially in the amino acid chemistry, on the behavior of other labile groups towards the reagents used in the protocols; fortunately, we were not concerned about both these factors as precursor-azides were prepared easily by standard protocols, and the present protocol can pave the way for accessing title compounds without affecting Boc, Cbz and Fmoc protecting groups, and benzyl and tertiary butyl groups in the side chains. The present strategy eliminates the need for the use of amines to obtain title compounds and thus, this method is step-economical; additional advantages include retention of chirality, convenient handling and easy purification. A few hitherto unreported compounds were also prepared, and all final compounds were completely characterized by IR, mass, optical rotation, and 1H and 13C NMR studies.
- Santhosh,Durgamma,Shekharappa,Sureshbabu, Vommina V.
-
p. 4874 - 4880
(2018/07/15)
-
- Sequential deprotectionecyclisation reaction: Stereoselective synthesis of azabicyclic β-enamino ester derivatives and (-) indolizidine 209D
-
This paper describes a new strategy for the stereoselective synthesis of pyrrolizidine and indolizidine based enamino esters and their acyl derivatives from L-proline. The key reaction in this process involves deprotection followed by ring closure of cyclic N-Boc amino-β-ketoesters. Also, the synthesis of 5R,9R- (-)-indolizidine 209D has been accomplished using this protocol.
- Ponpandian, Thanasekaran,Muthusubramanian, Shanmugam
-
p. 527 - 536
(2013/07/27)
-
- Enantioselective synthesis of (R)-homoboroproline from (S)-proline using a borylation approach
-
(S)-Proline was converted through a five-step sequence into (R)-homoboroproline hydrochloride in 29% overall yield with 97% The key step was the conversion of N-Boc iodomethylpyrrolidine into the corresponding pinacol boronate ester by an efficient copper(I)-catalyzed borylation reaction by using bispinacolatodiboron.
- Georgiou, Irene,Whiting, Andrew
-
experimental part
p. 4110 - 4113
(2012/09/08)
-
- The diastereoselective alkylation of arenesulfenate anions using homochiral electrophiles
-
A series of Boc-protected β-amino sulfoxides were prepared by the reaction of arenesulfenate anions with chiral Boc-protected β-amino iodides. The stereoselective substitution reaction is believed to arise through precoordination of the sulfenate counteri
- Soederman, Stefan C.,Schwan, Adrian L.
-
supporting information; experimental part
p. 4192 - 4195
(2011/10/08)
-
- Cobalt-catalyzed carbon-carbon bond formation: Synthesis and applications of enantiopure pyrrolidine derivatives[1]
-
In the presence of cobalt catalysts and tetramethylethylenediamine (TMEDA), the iodine atom in (S)-2-(iodomethyl)pyrrolidines was replaced by an aryl or an alkynyl group from the corresponding Grignard reagent, and the coupling products were obtained in good to excellent yields (16 examples; 75-94% yields). The scope and limitations of this protocol were examined. The stereochemistry of the pyrrolidines was unaffected by the reaction conditions. The coupling products are important building blocks of phenanthroindolizidine alkaloids. Palladium-catalyzed formal [4+2] cycloaddition of 2,2′-diiodobiphenyl with the thus-generated (S)-2-(3-trimethylsilyl-2-propynyl)pyrrolidine gave a good yield of the desilylated phenanthrene, which was then converted into unnatural (+)-(S)-tylophorine by the Pictet-Spengler cyclization. Copyright
- Hsu, Shih-Fan,Ko, Chih-Wei,Wu, Yao-Ting
-
supporting information; experimental part
p. 1756 - 1762
(2011/09/20)
-
- In situ trapping of Boc-2-pyrrolidinylmethylzinc iodide with aryl iodides: Direct synthesis of 2-benzylpyrrolidines
-
Addition of (S)-(+)-tert-butyl 2-(iodomethyl)pyrrolidine-1-carboxylate to activated zinc, aryl halides, and a catalyst derived from Pd2(dba) 3 (2.5 mol %) and SPhos (5 mol %) in DMF allows trapping of the corresponding organozinc rea
- Massah, Ahmad Reza,Ross, Andrew J.,Jackson, Richard F. W.
-
supporting information; experimental part
p. 8275 - 8278
(2011/03/18)
-
- Substituted Disulfonamide Compounds
-
Substituted disulfonamide compounds corresponding to formula I: In which R1, R2, R3, R4a, R4b, R5a, R5b, R8, R9a, R9b, R10, R11, a, b, s, t and A have defined meanings, pharmaceutical compositions containing one or more such compounds, processes for preparing such compounds, and a method of using such compounds for the treatment or inhibition of pain and/or other conditions mediated by the bradykinin receptor 1 (BR1).
- -
-
Page/Page column 34-35
(2010/06/22)
-
- Selenium promoted synthesis of enantiopure pyrrolidines starting from chiral aminoalcohols
-
Starting from commercially available enantiomerically pure aminoalcohols and using simple conversions promoted by organoselenium reagents, several enantiomerically pure substituted pyrrolidines were prepared. After double protections (R)- or (S)-2-phenylg
- Tiecco, Marcello,Testaferri, Lorenzo,Bagnoli, Luana,Scarponi, Catalina,Temperini, Andrea,Marini, Francesca,Santi, Claudio
-
p. 2758 - 2767
(2008/03/28)
-
- One-pot synthesis of orthogonally protected enantiopure S-(aminoalkyl)-cysteine derivatives
-
The general synthesis of a new class of non-natural diamino acids, 2-amino-3-[(2′-aminoalkyl)thio]propanoic acids or S-(aminoalkyl)cysteines, is reported. Under the conditions devised, enantiopure N-Boc-protected β-iodoamines, readily generated from proteinogenic α-amino acids, are treated with L-cysteine ethyl ester hydrochloride, using Cs2CO 3 as a base. The S-alkylation products, obtained in high yields (96-98 %) and without any detectable traces of accompanying byproducts, are hydrolysed to yield the free carboxyl group. An orthogonal protection is then introduced on the free amino group by treatment with Fmoc-OSu under standard conditions. The inclusion of one of these orthogonally protected diamino acids in a solid-phase growing pentapeptide is also reported. Wiley-VCH Verlag GmbH & Co. KGaA, 2006.
- Bolognese, Adele,Fierro, Olga,Guarino, Daniela,Longobardo, Luigi,Caputo, Romualdo
-
p. 169 - 173
(2007/10/03)
-
- Copper(I) mediated cross-coupling of amino acid derived organozinc reagents with acid chlorides
-
This paper describes the development of a straightforward experimental protocol for copper-mediated cross-coupling of amino acid derived β-amido-alkylzinc iodides 1 and 3 with a range of acid chlorides. The present method uses CuCN·2LiCl as the copper source and for organozinc reagent 1 the methodology appears to be limited to reaction with more stable acid chlorides, providing the desired products in moderate yields. When applied to organozinc reagent 3, however, the protocol is more general and provides the products in good yields in all but one of the cases tested. The Royal Society of Chemistry 2006.
- Hjelmgaard, Thomas,Tanner, David
-
p. 1796 - 1805
(2008/02/05)
-
- An efficient and convergent synthesis of the potent and selective H3 antagonist ABT-239
-
An efficient and convergent process for the preparation of a potent and selective H3 receptor antagonist, ABT-239, 1A was accomplished with an overall yield of 64%. The key step in the synthesis is a Sonogashira coupling/cyclization reaction of 1-but-3-ynyl-2-(R)-methylpyrrolidine (9) with 4′-hydroxy-3′-iodo-biphenyl-4-carbonitrile (3). Additionally, the key amine component 2-(R)-methylpyrrolidine (7) was effectively synthesized from the readily available Boc-l-prolinol with a simple catalytical hydrogenolysis as the key step. This column chromatography-free process is highlighted by several simple work-up and purification procedures and is amendable to the large-scale preparation of 1A.
- Ku, Yi-Yin,Pu, Yu-Ming,Grieme, Tim,Sharma, Padam,Bhatia, Ashok V.,Cowart, Marlon
-
p. 4584 - 4589
(2007/10/03)
-
- Pharmaceutical compositions and methods for use
-
The present invention relates to aryl olefinic azacyclic compounds and aryl acetylenic azacyclic compounds, including pyridyl olefinic cycloalkylamines and pyridyl acetylenic cycloalkylamines. The present invention also relates to prodrug derivatives of the compounds of the present invention.
- -
-
-
- Process for preparing 2-methylpyrrolidine and specific enantiomers thereof
-
The invention relates to a process for preparing 2-methylpyrrolidine and, more particularly, specific enantiomers of 2-methylpyrrolidine. Novel intermediates also are described.
- -
-
-
- Process for preparing 2-methylpyrrolidine and specific enantiomers thereof
-
The invention relates to a process for preparing 2-methylpyrrolidine and, more particularly, specific enantiomers of 2-methylpyrrolidine. Novel intermediates also are described.
- -
-
-
- Pharmaceutical compositions and methods for use
-
The present invention relates to aryl olefinic azacyclic compounds and aryl acetylenic azacyclic compounds, including pyridyl olefinic cycloalkylamines and pyridyl acetylenic cycloalkylamines. The present invention also relates to prodrug derivatives of the compounds of the present invention.
- -
-
-
- A short and concise synthetic route to (-)-coniceine
-
(-)-Coniceine, the simplest framework of indolizidine alkaloids, has been successfully accessed using a route in which ruthenium-catalyzed ring-closing olefin metathesis (RCM) was the key reaction to establish the unsaturated bicyclic lactam system.
- Park, So Hyun,Kang, Hyun Jung,Ko, Sangwon,Park, Soyoung,Chang, Sukbok
-
p. 2621 - 2624
(2007/10/03)
-