68485-52-9Relevant academic research and scientific papers
A New Method for the Carbon-extension Reactions of Azetidin-2-ones at the 4-Position
Kobayashi, Takeo,Ishida, Nobory,Hiraoka, Tetsuo
, p. 736 - 737 (1980)
High yields of 4-alkyl-, 4-allyl-, 4-vinyl-, or 4-ethynynl-azetidin-2-ones are obtained by treating 4-sulphonylazetidin-2-ones with either lithium organocuprates or Grignard reagents, but yields from 4-acetoxyazetidin-2-one with Grignard reagents are low.
Amidoalkylations with Allylic Silanes: a Facile Synthesis of the Carbapenem System
Kraus, George A.,Neuenschwander, Kent
, p. 134 - 135 (1982)
Amidoalkylation reactions with allylic silanes provide a direct route to the carbapenem ring system.
Ring-closing metathesis of vinyl fluorides towards α-fluorinated α,β-unsaturated lactams and lactones
Marhold, Michael,Stillig, Christian,Fr?hlich, Roland,Haufe, Günter
supporting information, p. 5777 - 5785 (2014/10/15)
Ring-closing olefin metathesis reactions (RCM) using Grubbs II or Hoveyda's catalysts have been applied to a series of N-alkenyl-N-benzyl-α-fluoroacrylamides. α-Fluoro-α,β-unsaturated γ- or δ-lactams incorporating a fluorinated double bond were obtained in moderate to good yields, depending on the nature of substituents on the benzyl ring. The corresponding seven- and eight-membered lactams were not formed under similar conditions. When the N-benzyl group was replaced by an N-tosyl group, the corresponding ε-lactam was also formed in 38% yield. When N-(2-fluoroallyl) derivatives were used instead of fluoroacryloyl derivatives, six-, seven-, and eight-membered N-heterocycles were obtained in low yields. This method was also used to synthesize fluorinated α,β-unsaturated analogues of pyrrolizidine and indolizidine alkaloids from prolinol, and also to synthesize N-benzyl-3-fluoroquinolone in three steps from commercially available 2-vinylaniline in 44% overall yield. Also 3-fluorocoumarin and 3-fluorochromene were prepared from ovinylphenol, and 3-fluoro-benzoxepine was available from o-allylphenol.
β-, γ- and δ-Lactams as conformational constraints in ring-closing metathesis
Tarling, Chris A.,Holmes, Andrew B.,Markwell, Roger E.,Pearson, Neil D.
, p. 1695 - 1701 (2007/10/03)
The azabicycloalkenones 5, 6 and 7 were formed in excellent yields via ring-closing metathesis of the bis-alkenyl precursors 1, 2 and 3.
Rapid entry into mono-, bi-, and tricyclic β-lactam arrays via alkene metathesis
Barrett, Anthony G. M.,Baugh, Simon P. D.,Christopher Braddock,Flack, Kevin,Gibson, Vernon C.,Giles, Matthew R.,Marshall, Edward L.,Procopiou, Panayiotis A.,White, Andrew J. P.,Williams, David J.
, p. 7893 - 7907 (2007/10/03)
4-Acetoxy-2-azetidinone and (3R,4R)-4-acetoxy-3-[(1R)-1-(tert- butyldimethylsilyl)-oxyethyl]-2-azetidinone were converted into 4-alkenyloxy- , 4-(N-allyltoluene-4-sulfonamido)-, 4-(allylthio)-, and 4-alkenyl-2- azetidinone systems. In addition, 4-acetoxy-2-azetidinone and (3R,4R)-4- acetoxy-3-[(1R)-1-(tert-butyldimethylsilyl)-oxyethyl]-2-azetidinone were converted into β-lactam dienes via sequential C-4 substitution using unsaturated alcohols, allyl mercaptan, N-allyltoluene-4-sulfonamide, and allyl(chloro)dimethylsilane followed by N-allylation. Crossed metathesis of β-lactam alkenes with styrene partners and ring closing metathesis of β- lactam dienes using the Schrock [(CF3)2MeCO]2Mo(=CHCMe2Ph)(=NC6H3-2,6- iso-Pr2) (1) or Grubbs Cl2(Cy3P)2Ru=CHPh (2) carbenes gave diverse monocyclic and bicyclic β-lactam systems including derivatives of 1- azabicyclo-[4.2.0]octan-8-one, 1-azabicyclo[5.2.0]nonan-9-one and its 6- thia, 6-aza, and 6-oxa analogues, 7-oxa-1-azabicyclo[6.2.0]octan-10-one,8- oxa-1-azabicyclo[7.2.0]octan-11-one, and 9-oxa-1-azabicyclo[8.2.0]octan-12- one. Ring-closing enyne metathesis and tandem ring-closing enyne and diene metathetic reactions were used to produce bicyclic β-lactam conjugated dienes as exemplified by the conversion of (3S,4R)-(-)-3-[(1R)-(tert- butyldimethylsilyl)oxyethyl]-1-(5-oxa-oct-7-en-2-yn-1-yl)-4-(2-propenyl)- azetidin-2-one (83) into (6R,7S)-(+)-7-[(1R)-(tert- butyldimethylsilyl)oxyethyl]-3-[(2,5-dihydro)-3-furanyl]-1- azabicyclo[4.2.0]oct-3-en-8-one (98).
Highly functionalised monocyclic and bicyclic β-lactams via alkene metathesis
Barrett, Anthony G. M.,Baugh, Simon P. D.,Gibson, Vernon C.,Giles, Matthew R.,Marshall, Edward L.,Procopiou, Panayiotis A.
, p. 155 - 156 (2007/10/03)
Both monocyclic and bicyclic β-lactam systems are prepared via alkene metathesis reactions using Mo(=CHCPhMe2)-(=NC6H3Pr(i)20[(OCMe(CF3)2]2 or Ru(=CHPh)Cl2(PCy3/
A new access to racemic carbacephems
Oumoch, Said,Rousseau, Gerard
, p. 997 - 1003 (2007/10/03)
A new approach to carbaccphems is reported involving the formation of the six-membered ring by cyclization of N-acyliminium ions. With methylene iminium species the reaction appeared general, while with (methoxycarbonyl)methylene iminium intermediates the
Synthesis of the Alkaloids Hopromine, Hoprominol and Hopromalinol, using Transamidation Methods
Crombie, Leslie,Haigh, David,Jones, Raymond C. F.,Mat-Zin, Ab. Rasid
, p. 2055 - 2068 (2007/10/02)
Synthesis of the unsymmetrical Homalium alkaloids hopromine, hoprominol and hopromalinol, in diastereoisomeric mixture form, is reported.The component eight-membered azalactams are first prepared.N-(3-Halogenopropyl)-4-pentyl- and -4-heptyl-azetidin-2-ones are aminated and ring expanded in liquid ammonia to give, after reductive methylation, the corresponding 4-alkyl-5-methyl-1,5-diazacyclooctan-2-ones.Synthesis of the 4-(2-hydroxyheptyl)-5-methyl-1,5-diazacyclooctan-2-one required for hoprominol and hopromalinol is carried out via 4-allyl β-lactam ring expansion to the eight-membered 4-allylazalactam, followed by methylation, epoxidation and epoxide opening with lithium dibutylcuprate.A similar epoxidation-cuprate sequence was carried out on the epoxypropyl β-lactam, as its N-tert-butyldimethylsilyl derivative, and led to a convenient copper-catalysed N- to O-migration of the protection; this migration is examined.Alkylation gave O-TBDMS-protected N-(3-chloropropyl)-4-(2-hydroxyheptyl)azetidin-2-one which could be aminated and transamidated in excellent yield, to give, after methylation, a superior sequence to the required eight-membered hydroxy azalactam.Although satisfactory for attachment of the first azalactam unit, a dibromobutane coupling system proved unreactive for the second.Couplings with unmethylated, methylated, and benzyloxycarbonyl-protected azalactams were examined using (E)-1,4-dibromobutene and (Z)-1,4-dichlorobutene as the bridging unit.Employing the latter, coupling the first N-methylated azalactam with potassium bis(trimethylsilyl)amide as the base, and then the second with bis(trimethylsilyl)amide-sodium hydride as the base system, provided a satisfactory synthetic outcome.Hydrogenation under acidic conditions gave the unsymmetrical structures hopromine, hoprominol and hopromalinol, as well as the more simple and symmetrical alkaloid, homaline.
BARBIER-TYPE ALLYLATION OF ACETALS WITH ALLYL BROMIDE IN A Pb/Al BIMETAL REDOX SYSTEM
Tanaka,Hideo,Yamashita, Shiro,Ikemoto, Youichi,Torii, Sigeru
, p. 1721 - 1724 (2007/10/02)
A novel mono and/or double allylation of acetals is achieved by the action of allyl bromide, aluminium metal, and a catalytic amount of PbBr2 and AlBr3 in tetrahydrofuran.
Synthesis and Reactivity of Novel Bicyclic &β-Lactams
Pfaendler, Rudolf,Strasser, Rupert
, p. 911 - 920 (2007/10/02)
The synthesis of the novel 8-oxo-1,3-diazabicyclooct-2-ene-2-carboxylates 1 is described as well as their enhanced reactivity under physiological conditions, compared with similar β-lactam compounds.
