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SYNOPSISBase-initiated polymerizations of N,N'-dimethyl-1,3-benzenedisulfonamide or other N,N'-dialkyldisulfonamides with various arylene-diglycidyl ethers afford a broad range of poly(hydroxy ether sulfonamides) (2). Polymers 2, which represent a new family of epoxy-based thermoplastics, are moldable, amorphous materials characterized by moderate T, "C) and by good barrier t o oxygen, reflected by oxygen transmission rates of 0.45-2.89 cc-mi1/100 in2-atm (0,)-day a t 234 "C and about 60% relative humidity. In addition to a discussion of how structural changes in the backbones of 2 influence their barrier properties, details of the synthesis, thermal analysis and mechanical evaluation of'the polymers are described. 0 1996 J o h n Wiley 8r Sons, Inc.

Fluorine nuclear magnetic resonance (F nmr) shielding has been investigated for an extensive series of p-fluoro-w'-and -p'-substituted benzophenones and their Lewis acid complexes in methylene chloride solution. This study appears to be the first systematic study of substituent nmr shielding effects in both the reactant and the product of a chemical reaction under common conditions. The p-fluorophenyl label is used to measure -charge density at the carbonyl carbon atom. It is concluded that the change in -charge density at the carbonyl carbon induced by the polar effect of the m'or p'-substituted phenyl group is directly proportional to the product of the value of the substituent and the carbonyl carbon atom charge density in the unsubstituted derivative. This result provides strong support for the hypothesis of Hammett.

The 1,2,4‐triazolo[1,5‐a]pyrimidine‐2‐sulfonamides are a new class of highly active herbicides. A novel cyclization method for the synthesis of these compounds is discussed.

New double 1,l-diphenylethylene (DDPE) compounds with different substituent groups on 1,3-bis(l-phenylethenyl)benzene (PEB) and samples of l,3-bis[ 1-(methylphenyl)ethenyl]benzene (MPEB) with different methyl group positions on the phenyl rings were prepared. Included in the preparation was also a non-DDPE diolefinic compound in which the center phenyl ring of PEB was replaced by a saturated one. The behavior of isoprene polymerization initiated by the dilithium initiators obtained by the addition reaction of sec-butyllithium (8-BuLi) with these diolefinic compounds was studied. The slow propagation from the initial initiator-isoprene adduct observed for the initiators based on PEB and W E B was not affected by any of the structural variations. Structural variations, however, had an influence on the relative reaction rate of the two double bonds on the diolefinic compounds with s-BuLi. Replacement of the center phenyl ring with a saturated cyclohexane ring drastically reduced the double bond reaction rate with s-BuLi. IntroductionA family of dilithium initiators (DLI) prepared by the addition reaction of see-butyllithium (s-BuLi) with compounds containing two 1,l-diphenylethylene functional groups (DDPE; double 1,l-diphenylethylene compounds) have been rep0rted.l Unlike other DLI, they can be made in hydrocarbon solvents without the presence of any polar additives. The reaction was swift, and the DLI can be made nearly free of residual reactants and other byproducts. Among the members of the DLI reported, the ones derived from the DDPE compounds, l,&bis(lphenyletheny1)benzene (PEB) and l,&bis[l-methylpheny1)ethenyll benzene (MPEB) are most interesting because of their solubilities in hydrocarbon solvents.2 Useful high strength styrene-butadiene-tyrene and other butadiene triblock copolymers3f4 have been prepared from these DLI. However, styrene-isoprene-styrene (SIS) triblock copolymer made from them was weak and had a broad bimodal molecular weight distribution.The formation of the bimodal distribution in isoprene polymerization has been attributed to the inadvertent presence of monofunctional initiator (MFI) in the DLI systems and the slow propagation from the initial addition product of isoprene with the DLL5 The initiation by a MFI and the subsequent propagation were fast, and the polyisoprene derived from it became the high molecular weight peak of the bimodal distribution. The initiation of isoprene by a DLI, though not slow, led to a very slow propagation from the initial addition product of isoprene with the initiator. The main peak of lower molecular weight and broader molecular weight distribution was the polyisoprene from the DLI. Complete elimination of MFI from any DLI system was difficult. As low as 2-3% of MFI would cause the formation of bimodal distribution and a deterioration of SIS properties.This slow propagation of isoprene from the initial DLIisoprene adduct was believed to be caused by a strong intramolecular association of the adduct. Polar additives, particularly N,lV,N'"",N''-pentameth...

The rates of the diaxial --t diequatorial rearrangement of 28,3a-dibromocholestane (Ia), and the analogous bromohydrin p-toluenesulfonates (Id and Ie) and anisates (If and Ig) have been measured in various solvents. T h e change in rate with variation in solvent was found to correlate with the change in the ionizing power of the solvents. T h e sensitivity of the rate of rearrangement t o changes in solvent ionizing power, as measured by the ratio of the rate of rearrangement in nitromethane to t h a t in decalin, was found to be smaller for the dibromide (Ia) than for the esters (Id to Ig). A detailed discussion of the mechanism of the reaction is presented. I t is proposed that the following factors (either singly or simultaneously) could lead to the smaller sensitivity to solvent change shown by the dibromide (Ia) a s compared with the esters (Id to Ig): (1) a difference in a postulated change of the axia1:equatorial opening ratio with change in solvent, and (2) the development of a smaller charge in the transition state for the rearrangement of the dibromide (Ia) as compared with that in the rearrangement of the esters, when the reactions are carried out in the less polar solvents. I t is argued that the operation of the latter factor would be most simply interpreted in terms of a merged ion-pair, cyclic-concerted mechanism, as initially suggested by Grob and Winstein.A merged ion-pair, cyclic-concerted mechanism for the diaxial -+ diequatorial rearrangement of (5a,6p-dibromocholestane was suggested in 1952 by Grob and Winstein (1). Their proposal, which was a significant modification of an earlier mechanism put forward by Barton and Miller (2)

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