155496-06-3Relevant academic research and scientific papers
Iodine-Catalyzed Synthesis of Chiral 4-Imidazolidinones Using α-Amino Acid Derivatives via Dehydrogenative N-H/C(sp3)-H Coupling
Kanyiva, Kyalo Stephen,Tane, Marina,Shibata, Takanori
, p. 12773 - 12783 (2019/09/09)
An efficient method for the asymmetric synthesis of 4-imidazolidinones via an iodine-catalyzed intramolecular N-H/C(sp3)-H activation of readily available and abundant feedstocks, amino acids, and amines is described. The reaction proceeded under visible light irradiation to afford a variety of 4-imidazolidinone derivatives under mild conditions in moderate to excellent yields. Secondary and tertiary C(sp3)-H bonds were aminated, and various functional groups were tolerated.
Stereoselective synthesis of activated 2-arylazetidines via imino-aldol reaction
Ghorai, Manas K.,Das, Subhomoy,Das, Kalpataru,Kumar, Amit
, p. 9042 - 9049 (2015/09/01)
A simple and efficient synthetic route to substituted N-sulfinyl and N-sulfonyl azetidines is described involving imino-aldol reaction of ester enolates with racemic and non-racemic aldimines for obtaining β-amino esters as a key step. These β-amino ester
Indium-mediated allylation of aldehydes, ketones and sulfonimines with 2-(alkoxy)allyl bromides
Dhanjee, Heemal,Minehan, Thomas G.
supporting information; experimental part, p. 5609 - 5612 (2010/10/21)
2-(Alkoxy)propenyl bromides are readily prepared from 1,3-dibromo-2- propanol in a two-step sequence involving hydroxyl protection and sodium hydride-induced dehydrobromination. Indium-mediated allylation of aldehydes, ketones, and sulfonimines with 2-(alkoxy)propenyl bromides furnishes the corresponding homoallylic alcohols and sulfonamines in good yields. The products can be easily transformed into β-hydroxy ketones and esters, as well as substituted dihydropyrans, and protected β-amino acids. Chiral 2-(alkoxy)propenyl halides, derived from (-)-menthol and d-glucal, furnish diastereomerically enriched products.
Synthesis and microbial transformation of β-amino nitriles
Winkler, Margit,Martínková, Ludmila,Knall, Astrid C.,Krahulec, Stefan,Klempier, Norbert
, p. 4249 - 4260 (2007/10/03)
Rhodococcus equi A4, Rhodococcus erythropolis NCIMB 11540 and Rhodococcus sp. R312 were investigated towards their ability to produce β-amino amides and acids from β-amino nitriles. The microorganisms show comparable trends: five-membered alicyclic 2-amino nitriles were transformed significantly faster than the six-membered compounds and the products of trans-2-amino nitriles (amides and acids) were formed considerably faster than the cis-counterparts (amides). The trans-five membered nitriles gave the amides (1b, 5b) in excellent enantiomeric excess (94-99%), the biotransformation of trans-six membered substrates resulted in the formation of the acid (3c, 7c) in excellent ee (87-99%). The ee's of the cis-compounds were throughout lower. Fifteen new substances were synthesized and characterized in the course of this work.
Total syntheses of the spermine alkaloids (-)-(R,R)-hopromine and (±)-homaline
Ensch, Corinne,Hesse, Manfred
, p. 1659 - 1673 (2007/10/03)
The diastereoselective synthesis of the spermine alkaloid (R,R)-hopromine (2) is described. The as yet unknown absolute configuration of naturally occurring (-)-hopromine (2) is (R,R) and was established by comparison of the reported specific rotation of the natural product with that of the synthetic one. Preparation of the characteristic bis-8-membered lactam scaffold was carried out by convergent build-up of basic chiral azalactam units 21a and 21b and subsequent iterative linking (Schemes 5 and 6). Key steps in the analogous syntheses of 4-alkyl-hexahydro-1,5-diazocin-2(1H)-ones 21a and 21b were the introduction of the unbranched alkyl side chains into their common precursor 14 via cuprate reaction and the Sb(OEt)3-assisted cyclization of the open-chain intermediates 20a and 20b, respectively (Schemes 3 and 4). The chiral iodoester 14 was prepared from commercially available (+)-L-aspartic acid (12). Based on the synthetic strategy developed for (R,R)-hopromine (2), a rapid access to the parent alkaloid homaline (1) in its (±)-form is given.
Cleavage of sulfonamides with phenyldimethylsilyllithium
Fleming, Ian,Frackenpohl, Jens,Ila, Hiriyakkanavar
, p. 1229 - 1235 (2007/10/03)
The toluene-p-sulfonamides of secondary amines and indoles are cleaved by treatment with phenyldimethylsilyllithium to give the secondary amines. Aziridine toluene-p-sulfonamides, however, are opened by attack of the silyllithium reagent on carbon to give β-silylethyl sulfonamides. The aziridine toluene-p-sulfonamide 22 derived from norbornene is different in giving the 2-[dimethyl(phenyl)silyl]-4-methylbenzenesulfonamide 23 of exo-norbornylamine. The aziridine toluene-p-sulfonamides 26, 28 and 30, derived from methyl cinnamate, methyl acrylate and cinnamyl acetate, are also anomalous, giving 3-[N-(p-tolylsulfonyl)amino]-3-phenylpropionic acid 27, {3-[N-(p-tolylsulfonyl)amino]propionyl}-dimethyl(phenyl)silane 29 and trans-cinnamyl alcohol 31, respectively, each derived by opening of the aziridine ring followed by loss of the silyl group.
Addition of a Reformatsky Reagent to N-Anthracene-9-sulfonyl and Related Imines: Synthesis of Protected β-Amino Acids
Robinson, Andrew J.,Wyatt, Peter B.
, p. 11329 - 11340 (2007/10/02)
The Reformatsky reagent tert-butoxycarbonylmethylzinc bromide adds in high yields to N-sulfonylimines, e.g. 1a-1d, derived by condensation of benzaldehyde dimethyl acetal with methanesulfonamide, toluene-4-sulfonamide, 4-(methoxycarbonyl)benzenesulfonamide and sulfamide: the products are protected β-amino acids 2a-2d.N-Deprotection occurs reductively (Na-naphthalene; low yields) for 2b and 2c or hydrolytically (refluxing aq. pyridine; 76percent yield of amino acid 3a after acid hydrolysis of the t-butyl ester) for the sulfamide derivatives 2d.Anthracene-9-sulfonamide (6) is readily available by sulfonation and chlorination of anthracene, and condenses with aldehydes , e.g. in the presence of TiCl4/Et3N, to yield imines 7a-7f, which after addition of tert-butoxycarbonylmethylzinc bromide give protected amino acids 8a-8f; however, 8f cyclizes to the sultam 9 via a spontaneous intramolecular Diels-Alder reaction.Reductive cleavage of the N-anthracene-9-sulfonyl group is much easier than for traditional N-sulfonyl protecting groups, as demonstrated by the deprotection of 8a and 8c using aluminium amalgam.
