Synthesis lactam

The allyl group was used to protect the nitrogen in a /3-lactam synthesis, but was removed in a four-step sequence. Whether a transition-metal-catalyzed isomerization to the enamide followed by hydrolysis is an effective cleavage procedure remains to be tested and warrants further study. ... 

The allyl group was used to protect the nitrogen in a j3-lactam synthesis, but was removed in a four-step sequence. ... 

Methylphenylsulfonyl)ethylamine was used to introduce the nitrogen in a j3-lactam synthesis. 

The azomethine ylide strategy for (3-lactam synthesis 99JHC1365. 

Activated carboxylic acids served as versatile precursors in lactam synthesis. Robl described some a-amino-c-alkyl-c-caprolactam syntheses, Eqs. (4-7)] [12]. Ring closure was induced after an EDC/HOBt activation of the acid function of 31 to form the 6-propyllactam 32 in 51 % yield, Eq. (4). The cyclization of... 

Scheme 12.43 Asymmetric 3-lactam synthesis using chiral NHCs...

ZnEt2 to chalcone with mercaptocam-phan-2-ol-derived hgand 96-7 A, 0-heterocycle ligands 120 (+)-5-e/7i-nojirimycin-5-lactam, synthesis of 338, 340 Noyori, Ryoji 2... 

Scheme 9.7. An asymmetric, three-component synthetic strategy for / -lactam synthesis.

Since the discovery and clinical introduction of penicillin, considerable industrial and academic effort has been addressed to the design and synthesis of /1-lactam antibiotics. However, among the numerous methods developed for / -lactam synthesis, no single method is compatible with all possible functional groups and/or the chirality needed on the /3-lactamic ring. 

Cycloaddition to endocyclic unsaturation has been used by many researchers for the preparation of isoxazoUdinyl adducts with y-lactams derived from pyrogluta-minol and is discussed later in this chapter as a synthesis of unusual amino acids (Scheme 1.20, Section 1.6) (79,80). A related a,p-unsaturated lactam has been prepared by a nitrone cycloaddition route in the total synthesis of the fungal metabolite leptosphaerin (81). A report of lactam synthesis from acyclic starting materials is given in the work of Chiacchio et al. (82) who prepared isoxazolidine (47) via an intramolecular nitrone cycloaddition reaction (Scheme 1.11). 

A unique tandem Staudinger-Wittig reaction finds application in lactam synthesis ... 

A new /3-lactam synthesis has been devised which relies on the formal ring contraction of the A3-pyrrolinone (271), readily prepared from commercially available mucochloric... 

Spirocyclic p-Lactams Synthesis and Biological Evaluation of Novel Heterocycles... 

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