5-BROMO-2-THIOPHENEGLYOXAL HYDRATE

A mixture of selenium dioxide (8.66 g, 78 mmol), water (2.8mL) and 1, 4-dioxane (75mL) was heated to reflux to dissolve all particulates (-15 min) before the addition of 2-acetyl- 5-bromothiophene(8 g, 39 mmol) in one portion. After refluxing for 15 hrs, the mixture was cooled to ambient temperature, filtered through diatomaceous earth (1.5' by 3'diameter), washed liberally with Et2O, and concentrated in vacuo to a yellow residue. The residue was subjected to Kugelrohr distillation (150 C/1 Torr) to yield a glyoxal as a yellow oil, which was immediately added to boiling water. Recrystallization from water, filtration, and drying (37 C and 5 Torr) yielded the glyoxal hydrate, 1- (5-bromo-thiophen-2-yl)-2, 2- dihydroxyethanone, as white-pink needles (6.723 g, 73percent). 1H NMR (300 MHz, DMSO-d6)6 5.43 (t, J= 6.1 Hz, 1H), 6.93 (d, J= 6. 1 Hz, 2H), 7.37 (d, J= 4.1 Hz, 1H), 7.81 (d, J= 4.1 Hz, 1H);13C NMR (300 MHz, DMSO-d6) 6 90.28, 122.32, 132.23, 135. 73, 141. 15, 189. 6.A mixture of selenium dioxide (8.66 g, 78 mmol), water (2.8 mL) and 1, 4-dioxane (75 mL) was heated to reflux to dissolve all particulates(~15 min) before the addition of 2-acetyl- 5-bromothiophene (8 g, 39 mmol) in one portion. After refluxing for 15 hrs, the mixture was cooled to ambient temperature, filtered through diatomaceous earth (1.5' by 3'diameter), washed liberally withEt2O, and concentratediiz vacuo to a yellow residue. The residue was subjected to Kugelrohr distillation(150 C/1 Torr) to yield a glyoxal as a yellow oil, which was immediately added to boiling water. Recrystallization from water, filtration, and drying(37 C and 5 Torr) yielded the glyoxal hydrate, 1- (5-bromo-thiophen-2-yl)-2, 2- dihydroxyethanone, as white-pink needles (6.723 g, 73percent). 1H NMR (300 MHz, DMSO-d6) 6 5.43 (t, J= 6.1 Hz, 1H), 6. 93 (d, J= 6.1 Hz, 2H), 7.37 (d, J= 4.1 Hz, 1H), 7.81 (d, J= 4.1 Hz, 1H);13C NMR (300 MHz, DMSO-d6) 6 90.28, 122.32, 132.23, 135. 73, 141. 15, 189. 6.

Molecular Weight:237.07
XLogP3:1.4
Hydrogen Bond Donor Count:2
Hydrogen Bond Acceptor Count:4
Rotatable Bond Count:2
Exact Mass:235.91428
Monoisotopic Mass:235.91428
Topological Polar Surface Area:85.8
Heavy Atom Count:11
Complexity:162
Covalently-Bonded Unit Count:1
Compound Is Canonicalized:Yes