6-membered ring lactams

Lactam, 6-membered ring Lactam, 5-membered ring... 

This polymer may be prepared by stirring the molten w-aminoundecanoic acid at about 220°C. The reaction may be followed by measurements of the electrical conductivity of the melt and the intrinsic viscosity of solutions in w-cresol. During condensation 0.4-0.6% of a 12-membered ring lactam may be formed by intramolecular condensation but this is not normally removed since its presence has little effect on the properties of the polymer. 

The pentacyclic core 15 of more complicated manzamines was built up by a final ring closure of the thirteen-membered ring lactam in 50% yield. The tetracyclic system and the alkyne unit of the reactant 13 supposed a pre-orientation, an intermediately formed activated pentafluorophenyl ester 14 led to the desired... 

Polymer bound HOBt as a catalyst was used in the synthesis of seven (23 % yield), nine (13%) eleven (5%) and thirteen-membered ring lactams (34%) [13c]. 

An auxiliary controlled enantioselective route to generate seven-membered ring lactams 75 used the a-alkylation of cyclic hydrazide derivatives 74. Initially, 6-chloro hydrazides 73,bearing the chiral information in the M-amino-pyrrolidine function underwent amidocyclization in the presence of a base. A subse-... 

A systematic investigation of the ring-closing metathesis of 138 in the synthesis of a range of fourteen-membered ring lactams 139 and lactones has been reported by Weiler. The geometry of the resulting double bond was determined, the position of the olefin was broadly varied. The ratios obtained were compared to that derived from molecular mechanics calculations, Eq. (15), Table 4 [34]. 

In analogy to Edstrom s experiments, the nine- and ten- membered ring lactams underwent regio and stereoselective transannular ring contractions to give the corresponding indolizidinones and quinolizidinones, respectively (vide supra Scheme 56) (Table 21) [61]. 

C-H-stretching vibrations C=0-stretching of 5-membered ring lactam (cyclol)... 

Scheme 14 Nine-Membered-Ring Lactam and Indolizidinone-type p-Turn PeptidoTnimetic 81 ...

Utilizing the Grubbs alkene metathesis reaction, Katzenellenbogen et al. 164 described the synthesis of the ten-membered-ring lactam p-turn mimetic 129 (Scheme 47, some experimental details given below) and prepared a mimetic 130 of the neuropeptide substance P, and in particular of the four C-terminal amino acid sequence -Phe8-Gly-Leu-Metn-. Compound 130 was unable to inhibit the binding of radiolabeled substance P. 

Electrophilic transannular cyclization of nine-membered ring lactam 129 led to formation of protected methyl 6-amino-8-iodo-5-oxooctahydroindolizine-3-carboxylates 130a and 130b in high yields (Equation 4) <20060L2851>. 

The determination of ring size of the product 1 was based on the 1R carbonyl absorption at 1680 cm-1, characteristic of the ftve-membered-ring lactam. The stereochemistry was determined on the basis of mechanistic considerations, since the reaction proceeds via an anti addition. Moreover only one product was detected in the cyclization starting from cycloalkenyl derivatives, the co-fusion of the bicyclic system 2 was observed131, l32. 

Intramolecularly, insertion of carbon monoxide into vinyl halides bearing a secondary amino group yields a-methylene five-, six- and seven-membered ring lactams. ... 

A photocatalytic oxidation takes place in a suspension of titanium(IV) oxide and five-membered or six-membered ring lactams. ... 

In the alkylation of lactams the equilibrium position also lies at the side of the iminium compounds (80 equation SO), so it is not surprising that 4- to 12-membered ring lactams have been methylated by dimethyl sulfate to produce the corresponding cyclic iminium salts. "... 

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