4-hydroxybenzaldehyde We supply and sell intermediates products such as: 1. P-toluene sulfonamide cas: 70-55-3 (other names: ptsa, para toluene sulfonamide, p-toluenesulphonamide, 4-methylbenzenesulfonamide, 4-toluenesulfonamide) 2. P-toluene sulfonyl chloride cas:98-59-9 (other names: ptsc; para sulfonyl chloride;tosyl chloride; 4-toluene sulfochloride; 4-methylbenzenesulfonyl chloride; p-toluenesulfonyl chloride; toluene-4-sulfonyl chloride; 4-toluolsulfonyl chloride; p-tosyl chloride, p-toluene sulfochloride, 4-toluenesulfonic acid, chloride) 3. O/p-toluene sulfonamide cas:1333-07-9 (other names: optsa; o/p-toluene sulfonamide; o/ptsa; o, p-toluene sulfonamide; toluene sulphonamide ;mixed isomers) 4. 4-hydroxybenzaldehyde cas: 123-08-0 (other names: phba; p- hydroxybenzaldehyde; 4-formylphenol) 5. Ortho toluene sulfonamide cas: 88-19-7 (other names: o- toluene sulfonamide o-toluenesulphonamide ;otsa; 2-methylbenzenesulfonamide; 2-methylbenzene-1-sulfonamide; 2-toluene suldonamide; ortho toluene sulfonamide; o-toluene sulfonamide) 6. N-ethyl-o/p-toluene sulfonamide cas: 26914-52-3 (other names: n-optsa; ethyltoulenesulfonamide; n-ethyltoluenesulfonamide; noptsa).