Process for the preparation of certain substituted sulfilimines
View Patent ↗Cyano-substituted sulfilimines and sulfoximines are produced efficiently and in high yield from the corresponding sulfides by reaction with cyanamide and hypochlorite.
1. A process comprising oxidizing a sulfilimine to a sulfoximine in the scheme below
wherein
X is a C 1 -C 4 haloalkyl; and
R1 is a C1-C4; R2 and R3 are each independently a H or C 1 -C 4 alkyl;
wherein said oxidizing is conducted in the presence of a pH modifier, where said pH modifier has a pKa value in the range of about 2 to about 6, and the molar ratio of said pH modifier to sulfilimine starting material is about 0.3 to about 1.
2. A process according to claim 1 which is conducted in the presence of sodium permanganate in a mixture of acetonitrile and water as the reaction medium.
3. A process according to claim 1 wherein said pH modifier is selected from acetic acid, propionic acid, benzoic acid, potassium hydrogen sulfate, phosphoric acid, or mixtures thereof.
4. A process according to claim 1 wherein the pKa of said pH modifier is from about 2 to about 5.
5. A process according to claim 1 wherein said sulfilimine is N-Cyano-S-methyl-S-[1-(6-trifluoromethyl-3-pyridinyl)ethyl]sulfilimine.
6. A process according to claim 1 wherein said sulfoximine is N-Cyano-S-methyl-[1-(6-trifluoromethyl-3-pyridinyl)ethyl]sulfoximine.