Phosphorus functional antimicrobial coatings for metal surfaces

A process for preparing a quaternary ammonium mono-phosphonate acid free compound of formula (I)

• wherein R1 and R2 are independently methyl, ethyl, isopropyl or n-propyl;
• m is 15, 16, 17, 18 or 19;
• n is 0, 1, 2, 3, 4, 5 or 6;
• and X is chloro, bromo or iodo, comprising the steps of (a) reacting a compound of formula (II)
• wherein R is independently methyl, ethyl, isopropyl, n-butyl or phenyl, with a compound of formula (III)
• wherein X and n are as above and Y is a halogen selected from chloro or bromo to give a compound of formula (IV)
• (b) reacting the compound of formula (IV) with a compound of formula (V)
• wherein R1 and R2 are independently methyl, ethyl, isopropyl or n-propyl, and m is 15, 16, 17, 18 or 19, to give a compound of formula (VI)
• and (c) reacting a compound of formula (VI) with SiR3R4R5Z wherein R3, R4 and R5 are independently methyl or ethyl and Z is chloro, bromo, iodo or triflate in the presence of dichloromethane (DCM) between 8 to 12 hours at room temperature, or a mineral acid selected from HCl, HBr or HI to give a compound of formula (I), wherein the compound of formula (I) is isolated in pure form without chromatographic purification.