A Convenient One-Pot Synthesis of α-Isothiocyanatoethers and Unusual Course of Some of Its Nucleophilic Displacement Reactions

Bernát, Juraj; Kristián, Pavol; Guspanová, Jana; Imrich, Ján; Busova, T.

doi:10.1135/cccc19971491

Cited by 7 publications

(1 citation statement)

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“…Diphenyl isothiocyanophosphate is also used as an automated carboxy-terminal sequence analysis of peptides and proteins. 6 Kristian and coworkers 7 have developed a new simple method for preparation of αisothiocyanatoethers from P(=O)(NCS)3 or (PhO)2P(=O)NCS with an equimolar mixture of aldehydes and alcohols.…”

Section: Introductionmentioning

confidence: 99%

Kinetics and Mechanism of the Pyridinolysis of Aryl Phenyl Isothiocyanophosphate in Acetonitrile

Adhikary¹,

Lee²,

Lee³

2003

Bulletin of the Korean Chemical Society

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The kinetics and mechanism of the pyridinolysis (XC5H4N) of Y-aryl phenyl isothiocyanophosphates (1; (YC6H4O)(C6H5O)P(=O)NCS) are investigated in acetonitrile at 55.0 o C. The Hammett plots for substituent (Y) variations in the substrate (log k2 vs σ Y) exhibit a convex upward biphasic type with breaks at Y = H. For electron-donating Y groups the Hammett coefficients, ρ Y, are positive and cross-interaction constant ρ XY is negative, while those for electron-withdrawing Y groups ρ Y values are negative with a positive ρ XY. These results are interpreted to indicate mechanistic change at the breakpoint (σY = 0) from a concerted to a stepwise mechanism with rate-limiting expulsion of the − NCS group from a trigonal bipyramidal pentacoordinated (TBP-5C) intermediate. Biphasic plots of log k2 vs σ X or pKa(X) with steeper slopes for the more basic nucleophiles are obtained suggesting an equatorial nucleophilic attack in contrast to an apical attack for the less basic nucleophiles with smaller magnitude of ρ X or β X.

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Section: Introductionmentioning

confidence: 99%