Anti-Bredt bridgehead nitrogen compounds in ring-opening polymerization

Beyond the Diketopiperazine Family with Alternatively Bridged Brevianamide F Analogues

“…Following general procedure A on a 0.7 mmol scale, compound 12b was obtained after pTLC: yield 46% (0.097 g); white powder; R f = 0.22 (CH 2 Cl 2 /2% MeOH); mp 210−218°C; [α] D 25 = −102.5 (c = 0.38 in CHCl 3 ); 1 H NMR (300 MHz, CDCl 3 ) δ = 1. 76−2.18 (m, 4H), 2.68 (s, 1H), 2.92−3.01 (m, 1H), 3.04 (d,J = 16.5 Hz,1H),3.18 (dd,J = 16.5 Hz,J = 6.3 Hz,1H),3.79 (dd,J = 10.7 Hz,J = 4.7 Hz,1H), 4. 03− 4.15 (m, 1H), 4.23 (d,J = 6.3 Hz,1H),7.14 (dd,J = 7.8 Hz,J = 7.8 Hz,1H),7.24 (dd,J = 7.8 Hz,J = 7.8 Hz,1H),7.37 (d,J = 7.8 Hz,1H),7.48 (d,J = 7.8 Hz,1H),8.25 (s,1H) ppm; 13 C NMR (100 MHz, CDCl 3 ) δ = 21.…”

“…76−2.18 (m, 4H), 2.68 (s, 1H), 2.92−3.01 (m, 1H), 3.04 (d,J = 16.5 Hz,1H),3.18 (dd,J = 16.5 Hz,J = 6.3 Hz,1H),3.79 (dd,J = 10.7 Hz,J = 4.7 Hz,1H), 4. 03− 4.15 (m, 1H), 4.23 (d,J = 6.3 Hz,1H),7.14 (dd,J = 7.8 Hz,J = 7.8 Hz,1H),7.24 (dd,J = 7.8 Hz,J = 7.8 Hz,1H),7.37 (d,J = 7.8 Hz,1H),7.48 (d,J = 7.8 Hz,1H),8.25 (s,1H) ppm; 13 C NMR (100 MHz, CDCl 3 ) δ = 21. 3, 24.9, 28.2, 44.4, 58.2, 68.5, 77.0, 109.3, 111.5, 119.3, 120.4, 123.6, 126.6, 134.3, 136.0, 169.3 (6S,13R,13aR)-13-Chloro-1,2, 3,6,7,12,13,13a-octahydro-5H-6,13-epiminopyrrolo[1′,2′:1,2]azocino[4,5-b]indol-5-one (12c).…”

“…The residual white precipitate was redissolved in chloroform (10 mL) and washed three times with water. After the organic phase was dried over MgSO 4 , the solvent was removed by evaporation to give compound 14b as a white solid (96%): yield 96% (285 mg (d,J = 7.8 Hz,1H),7.50 (d,J = 7.8 Hz,1H),8.09 (s,1H) ppm; 13 C NMR (100 MHz, CDCl 3 ) δ = 21. 5, 24.4, 25.5, 43.5, 51.3, 57.8, 66.6, 83.6, 111.2, 111.3, 119.0, 120.0, 122.8, 126.9, 133.2, 136.1, 171.3 General Procedure B: Synthesis of Derivatives 14c−j.…”

Synthesis and Polymerizability of Atom-Bridged Bicyclic Monomers

“…However, the N-bridgehead urethanes 26 and 28 were sufficiently stable to be isolated because of the resonance stabilization provided by electron donation from the oxygen adjacent to the carbonyl [20][21][22]. This topic has been reviewed [23]. [20] 2.4.…”

Base Strengths of Substituted Tritylamines, N‐Alkylanilines, and Tribenzylamine in Aqueous Solution and the Gas Phase: Steric Effects Upon Solvation and Resonance Interactions

“…The resonance energy (RE) in normal amides is about 85 kJ·mol Ϫ1 , [39] so the reduction being proposed here is not more than about 50%. Such a reduction would not be expected to be detectable in the IR stretching vibration of the carbonyl bond as 1-azabicyclo-[3.3.1]nonan-2-one (8), whose cage structure leads to a reduction in RE of about 60%, still has an amide carbonyl vibration at 1680 cm Ϫ1 , [40] i.e. within the normal range for a tertiary amide.…”