Lactam preparation

Smith M. B. N-Dienyl Amides and Lactams. Preparation and Diels-Alder Reactivity Org. Prep. Proced. Int. 1990 22 315-397... 

The electrophilic fluorination of chiral bicyclic lactams (prepared from the epimers of pyroglutamic acid) by means of A-fluoro sulfonimide (NFSI) yields l- and d-4, 4-difluoroglutamic acids and 4,4-difluoroglutamines (Figure 5.21). They have also been prepared with a good ee starting from ethyl (/ )-bromodifluoroalaninate. ... 

B. Hexahydro-6-ethyl-3-(hydroxymethyi)-6-allyl-2-phenyl[2S,3S,6S,8aR]-5-oxo-5H-oxazolo[3,2-a]pyridine. In an oven-dried, 500-mL, round-bottomed flask, containing a magnetic stirring bar, is placed 14.4 g (55.2 mmol) of dry bicyclic lactam prepared in Part A. The flask is flushed with argon and filled with 150 mL of anhydrous tetrahydrofuran (Note 4) and then sealed with a rubber septum. The air in the flask is further replaced by argon (Note 5). After dissolution of the bicyclic lactam, the flask is cooled in dry ice/acetone and the solution is stirred while preparing lithium diisopropylamide (LDA). 

The synthesis of fused alicyclic ft-lactams by the four-center three-component Ugi reaction (U-4C-3CR) on a solid support has been reported. Also, resins have been used as scavengers in the purification of fused /3-lactams prepared in the solution phase <2004MI215>. 

A-Dienyl lactams, preparation and Diels-Alder reactions 90OPP315. 

The reduction of substituted 4-hydroxy-5,6-dihydropyrimidins such as VIII/ 114 is a reaction used several times as key step in the syntheses of polyamine alkaloids, Scheme VIII/21. In the presence of NaCNBH3/AcOH at 50°, ring enlarged azalactams of type VIII/115 are obtained in yields of about 90 %. Aza-lactams, prepared by this method, are nine- [65], thirteen- [66], and seventeen-membered [67] [68] [69]. 

Scheme 15 fS-Lactam preparations via cobalt salophen complexes... 

The first 2-azetidinone O-lactam) was obtained by Staudinger from the reaction of diphenylketene with benzylideneaniline (equation 13). Most of the -lactams prepared by this method have been made from imines derived from aromatic carbonyl compounds and ketoketenes. - The reaction of ketene itself with imines has been recently reinvestigated. Good yields of 3-lactams are obtained when a stream of ketene gas is passed through Ae imine in the absence of solvent (equations 14 and IS). No [4 + 2] cycloadduct is formed with N-cinnamylideneaniline. 

Dipolar Additions (30) -Lactam Preparations (12) Ni-Coupling Reactions (3) Enamine Rearrangement (1)... 

A-Dienyl amides and lactams. Preparation and Diels-Alder reactivity . Smith, M. B.,... 

FIGURE 9.10 Perfluorinated lactams prepared by hydrolysis of perfluorinated cyclic amines. 

Several syntheses of carbon-14 labeled taxols have been reported. N-3 -[Carbonyl- " C]-taxol 11.1.1 was prepared by coupling a [carbo-nyl- C]-A -benzoyl- 5-lactam with 7-(triethylsilyl)baccatin III (378), while the same group prepared [3 - " C]-taxol 11.1.2 by using a / -lactam prepared from carbonyl- " C-benzaldehyde (379). [3 - " C]-Docetaxel 11.1.3 was prepared by attachment of a labeled cinnamoyl side chain to 7,10-ditroc-10-deacetylbaccatin III, followed by hydroxyamination of the side chain (380). A slightly different approach was used to prepare [2, 3 - " C2]taxol, in that the required doubly labeled /3-lactam synthon was prepared using a doubly labeled Oppolzer s bromoacylbomanesul-tam intermediate (381). 7-([carbonyl- C]-acetyl)taxol was prepared by simple acylation of 2 -(triethylsilyl)taxol with [carbonyl--acetic anhydride and deprotection (382). The taxol analog PNU-105298 (4.1.3.12) was also prepared in both deuterium and carbon-14 labeled forms in both cases the label was placed on the side chain (383). 

Chiral P-lactams prepared from a 6-imino-D-galactose derivative have been used as synthons for 6-epz-lincosamine. ... 

This reagent serves as a precursor to stereochemically defined, fully substituted amide enolates and so provides a method for stereoselective quaternary carbon formation. The two-electron reduction of a,a-dialkylated bicyclic thioglycolate lactams, prepared by sequential alkyaltion of lactam in THE with EDA... 

Tricarbonyliron lactone complexes have also been used as precursors for /3-lactam preparation. Reaction of the complex (9), which is readily available from butadiene, with a protected amino-acid leads to a new lactam complex, which on oxidation gives a /3-lactam related to the nocardicins (Scheme 29). ... 

N-Dienyl Amides and Lactams Preparation and Diels-Alder Reactivity" Smitll.JJ.P. Org. Prep. Proceed. Int., 1990, 22, 315. 

---