The SRN1 mechanism in heteroaromatic nucleophilic substitution. Photostimulated reactions of halopyridines with ketone enolates

Novel block copolymers of 2-vinylpyridine and ɛ-caprolactone: Synthesis and characterization

“…The methine hydrogen can be observed separately at 3.93 ppm, which constitutes proof for the connection between the two blocks. This value agrees well with NMR spectra reported for structurally similar compounds 31,32) . Furthermore, the ratio of the integrals of the chain end resonances of the PCL block at 3.65 ppm and the methine hydrogen at 3.93 ppm is 2, as expected.…”

Solvent effects in heteroaromatic SRN1 reactions

“…The poor reactivity of lithioacetone with 1 in THF (experiments 49 and 50) provides another example of the generally low reactivity of lithio ketones toward heteroaromatic halides. 18,19 This cation effect, which may result from unfavorable ion-pairing and aggregation, is currently under investigation in our laboratories.…”

Practical preparation of 4(R)-allylazetidinones and 4(R)-(1-methylallyl)azetidinones

“…1.04 (s, 9), 1.11 (d, =7 = 6.5 Hz, major isomer, CH3CH2OSi), 1.15 (d, J = 6. 5 Hz, minor isomer, CH3CH2OSi), 1.34 (t, «7 = 7 Hz, minor isomer, SCH2CH3) 1.38 (t, «7 = 7 Hz, major isomer, SCH2CH3), 2.50-2.84 (m, 2), 3.40 (dt, = 5.5, 2 Hz, minor isomer, H-3), 3,56 (dt, J = 3.5, 2 Hz, major isomer, H-3), 4.26-4.60 (m, 2), 7.12 (br, 1), 7.32-7.80 (m, 10). Anal.…”

“…Anal. Caled for CggHggNOgSi: C, 69.13; H, 8.32; N, 3.51. Found: C, 69.00; , 7.80; N, 3.58. 3(S)-(Fluoroethyl)-4(fl)-[(ethoxythiocarbonyl)thio]-2oxoazetidine (7d): white solid; mp 82-84 °C dec; [apD +283.8°( c 1.03, CHClg); NMR (CDC13) 1.46 (t, 3, «7= 7 Hz), 1.50 (dd, 3, «7= 24, 6.5 Hz), 3.36 (dddd,1,«7 = 23.5,5.5,2.5,1 Hz,4.69 (d,2,«7 = 7 Hz), 5.12 (ddq, 1, «7 = 48, 6.5, 5.5 Hz, H-3a), 5.50 (d, 1, =7= 2.5 Hz, H-4), 6.76 (br, 1). Anal.…”