920-37-6Relevant articles and documents
Preparation of α-haloacrylate derivatives via dimethyl sulfoxide-mediated selective dehydrohalogenation
Li, Wei,Li, Jianchang,Wan, Zhao-Kui,Wu, Junjun,Massefski, Walter
, p. 4607 - 4610 (2008/03/13)
(Chemical Equation Presented) Dimethyl sulfoxide causes α/β-dihalopropanoate derivatives to undergo efficient, selective dehydrohalogenation to form α-haloacrylate analogues. A variety of α-halo Michael acceptors were prepared in dimethyl sulfoxide under mild, base-free conditions, including the preparation of α-bromoacrolein and α-chloro- and bromoacrylonitriles. Synthesis of these molecules has been reported in the literature to be difficult. Among all the existing dehydrohalogenation procedures, this protocol is the most facile, practical, and environmentally benign process.
Thienylpyrrole fungicidal agents
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, (2008/06/13)
There are provided fungicidal thienyl- and furylpyrrole compounds of formula I STR1 Further provided are compositions and methods comprising those compounds for the protection of plants from fungal infestation and disease.
Elimination reactions: Experimental confirmation of the predicted elimination of (β-cyanoethyl)sulfonium ions through a concerted, E2 mechanism
Banait, Narinder S.,Jencks, William P.
, p. 6950 - 6958 (2007/10/02)
Extrapolation of the lifetimes of carbanion intermediates formed in the elimination reactions of a series of β-cyanoethyl thioethers with different leaving groups (J. Am. Chem. Soc. 1988, 110, 5087-5095) predicts that the carbanions will not have a significant lifetime for pKlg a 2SO/H2O, 25.0 °C). Values of βlg obtained from Br?nsted-type plots of log kB against the estimated pKa values of the leaving groups, decrease from 0.39 to 0.24 with increasing pKa of the base catalyst. The changes in β and βlg are described by the interaction coefficient pxy=d?βlg/?pK BH=?βlg/?KBH=0.026. The deuterium isotope effect for proton removal from Ph-S+(Me)-CH2CL2CN is kH/kD=4.4 and 4.9 for tris(hydroxymethyl)aminomethane and ethylamine buffers, respectively, and there is no detectable protium exchange into the deuterated substrate. The positive pxy coefficient provides evidence for coupling between proton abstraction and leaving group expulsion; it confirms the concerted AxhDHDN (E2) mechanism. The values of β and βlg indicate an imbalance in the transition state, in which proton transfer is ahead of leaving group expulsion. The change from a stepwise AxhDHH+DNN (ElcB) mechanism for thiophenoxide leaving groups to a concerted mechanism for sulfide leaving groups is consistent with the notion that the mechanism is determined solely by the lifetime of the carbanion; there is no evidence for the coexistence of stepwise and concerted mechanisms.