Patent ID: 8735620

Claim:
A process for preparing a compound of the Formula 29 the process comprising (i) condensing sulfonylacetic acid compound 25 with 2,4,6-trimethoxy benzaldehyde compound 19 in the presence of a base to produce unsaturated sulfone compound 26; (ii) removing the tosyl group by treating unsaturated sulfone compound 26 with sodium hydroxide that yields styryl benzyl sulfone compound 20 and (iii) converting compound 20 to compound 29 by using a phoshorylation process using phosphorous oxychloride, wherein the phoshphorylation process is performed according to Scheme 7 comprising: (a) phosphorylating styryl benzyl sulfone compound 20 with phosphorous oxychloride under basic conditions using a neutralizing base to yield 3-O-dichloro phosphate of compound 20 that is free of impurities; (b) treating 3-O-dichloro phosphate of compound 20 obtained in step (a) first with ice and then with aqueous potassium hydroxide and then treating with aqueous HCl to yield precipitate of the phosphoric acid derivative of compound 20 as a light yellow solid, compound 28; and (c) treating compound 28, with an alkali in an organic solvent to yield alkali metal-O-phosphate, compound 29 at pH 8; and (d) filtering and washing compound 29 with acetone and drying under vacuum to obtain a pure compound 29.