3-Hydroxy-4-nitrobenzaldehyde

To a stirring solution of 3- hydroxybenzaldehyde 23 (618 mg, 5.0 mmol) in dichloromethane (10 mL) was added tetrabutylammoniumhydrogen sulfate (85.0 mg, 0.25 mmol) and isopropyl nitrate (1.27 mL, 12.5 mmol). Concentrated sulfuric acid (610 μ) was added dropwise and the resulting reaction mixture was allowed to stir at room temperature for 15 minutes. The reaction contents were then transferred to a separatory funnel containing 50 mL of an aqueous saturated sodium bicarbonate solution. Dichloromethane was then used to extract the crude product. The combined organic layers were dried with anhydrous sodium sulfate, filtered and concentrated in vacuo. The resulting solid was adsorbed onto silica gel and purified via flash column chromatography eluting with 99: 1 to 4: 1 hexanes:ethyl acetate to give isomer 30 (R = 0.44 in 3: 1 hexanes:ethyl acetate) as a yellow solid (201 mg, 24percent yield) followed by the desired product 28 (R/= 0.19 in 3: 1 hexanes:ethyl acetate) as a pale yellow solid (411 mg, 47percent yield). This is a known procedure (D. A. Learmonth (Portela & C.A., S.A., Port.), GB- 2377934, 2003). We were able to obtain 28 (CAS number: 42123-33-1) in 63percent yield during the course of these investigations. Characterization Data for Compound 28:

Molecular Weight:167.12
XLogP3:1.5
Hydrogen Bond Donor Count:1
Hydrogen Bond Acceptor Count:4
Rotatable Bond Count:1
Exact Mass:167.02185764
Monoisotopic Mass:167.02185764
Topological Polar Surface Area:83.1
Heavy Atom Count:12
Complexity:188
Covalently-Bonded Unit Count:1
Compound Is Canonicalized:Yes