51355-59-0

Upstream product

• 1499-17-8 o-phenylene chlorophosphate 
• 62-53-3 aniline 

Relevant academic research and scientific papers

Kinetics and mechanism of the anilinolysis of (2R,4R,5S)-(+)-2-chloro-3,4- dimethyl-5-phenyl-1,3,2-oxazaphospholidine 2-sulfide in acetonitrile

The nucleophilic substitution reactions of (2R,4R,5S)-(+)-2-chloro-3,4- dimethyl-5-phenyl-1,3,2-oxazapho-spholidine 2-sulfide (3) with substituted anilines (XC6H4NH2) and deuterated anilines (XC6H4ND2) are investigated kinetically in acetonitrile at 5.0 °C. The anilinolysis rate of 3 involving a cyclic five-membered ring is considerably fast because of small negative value of the entropy of activation (ΔS≠ = -2 cal mol-1 K -1) over considerably unfavorable enthalpy of activation (ΔH≠ = 18.0 kcal mol-1). Great enthalpy and small negative entropy of activation are ascribed to sterically congested transition state (TS) and bulk solvent structure breaking in the TS. A concerted S N2 mechanism with a backside nucleophilic attack is proposed on the basis of the secondary inverse deuterium kinetic isotope effects, k H/kD 1.

Kinetics and mechanism of the pyridinolysis of (2R,4R,5S)-(+)-2-chloro-3,4- dimethyl-5-phenyl-1,3,2-oxazaphospholidine 2-sulfide in acetonitrile

The nucleophilic substitution reactions of (2R,4R,5S)-(+)-2-chloro-3,4- dimethyl-5-phenyl-1,3,2-oxa-zaphospholidine 2-sulfide with X-pyridines are investigated kinetically in acetonitrile at 5.0 °C. The free energy relationships for substituent X variations in the nucleophiles exhibit biphasic concave upwards with a break point at X = 3-Ac. Unusual positive ρX (= +4.73) and negative βX (= -0.75) values are obtained with the weakly basic pyridines, and rationalized by the isokinetic relationship with isokinetic temperature at tISOKINETIC = 39.3 °C. A concerted mechanism involving a change of nucleophilic attacking direction from a frontside attack with the strongly basic pyridines to a backside attack with the weakly basic pyridines is proposed on the basis of greater magnitudes of selectivity parameters (ρX = -6.15 and βX = 1.11) with the strongly basic pyridines compared to those (ρX = 4.73 and βX = -0.75) with the weakly basic pyridines.

Kinetics and mechanism of the anilinolysis of 1,2-phenylene phosphorochloridate in acetonitrile

The nucleophilic substitution reactions of 1,2-phenylene phosphorochloridate (1) with substituted anilines (XC6H 4NH2) and deuterated anilines (XC6H4ND2) are investigated kinetically in acetonitrile at -15.0 °C. The studied substrate of 1,2-phenylene phosphor°Chloridate is cyclic five-membered ring of phosphorus ester, and the anilinolysis rate of 1 is much faster than its acyclic analogue (4: ethyl phenyl chlorophosphate) because of extremely small magnitude of the entropy of activation of 1 compared to 4. The Hammett and Broensted plots exhibit biphasic concave upwards for substituent X variations in the nucleophiles with a break point at X = 3- Me. The values of deuterium kinetic isotope effects (DKIEs; kH/kD) change from secondary inverse (kH/kD 1) with the weakly basic anilines. The secondary inverse with the strongly basic anilines and primary normal DKIEs with the weakly basic anilines are rationalized by the transition state (TS) variation from a predominant backside attack to a predominant frontside attack, in which the reaction mechanism is a concerted SN2 pathway. The primary normal DKIEs are substantiated by a hydrogen bonded, four-center-type TS.

Syntheses und NMR-Spektren phosphororganischer Antioxidantien und verwandter Verbindungen

The syntheses of various aliphatic, aromatic, sterically hindered, and cyclic organophosphorus compounds (phosphorous acid esters, esters chlorides and ester amides, hydrogen phosphites, phosphinates and phosphates) are reported, and general procedures for preparation are given.The compounds synthesized were investigated by means of 31P-, 1H- and 13C-n.m.r. spectroscopy, and the chemical shifts measured are listed.