Cyanogen Bromide → HCID 178508160, compound

HRID 2283141Notes

Reaction equation

Cl.Cl.[N:3]1[NH:4][N:5]=[N:6][C:7]=1[C:8]1[CH:9]=[C:10]([NH2:15])[C:11]([NH2:14])=[CH:12][CH:13]=1.[N:16]#[C:17]Br.[OH-].[Na+]>O>[N:6]1[NH:5][N:4]=[N:3][C:7]=1[C:8]1[CH:13]=[CH:12][C:11]2[NH:14][C:17]([NH2:16])=[N:15][C:10]=2[CH:9]=1

Participants

Conditions

Temperature: 4 °C

Procedure

To 4-(2H-tetrazol-5-yl)-benzene-1,2-diamine dihydrochloride (8.56 g, 34 mmol) in water (45 ml) was adjusted to pH 6.0. Cyanogen bromide (3.91 g, 37 mmol) was added and the mixture stirred for 4 hours. The reaction mixture was analyzed by HPLC. The pH of the reaction mixture was adjusted to pH 4.0 with 40% (v/v) sodium hydroxide. The mixture was cooled to 4° C. and the brown solid filtered and washed with water. The material was dried to yield a brown solid 5-(2H-tetrazol-5-yl)-1H-benzimidazol-2y-amine (4.10 g) with a purity of 88%, Rt=7.3 mins. To a suspension of crude 5-(2H-tetrazol-5-yl)-1H-benzimidazol-2-ylamine (4.10 g) in water (40 ml), the pH was adjusted to 1.2 with 50% (v/v) hydrochloric acid. Activated carbon was then added (0.2 g) and the mixture stirred for 18 hours. The mixture was filtered and the pH of the filtrate adjusted to pH 3.7 to yield a tan colored solid. The material was dried (3.01 g) and had a purity of >97% by HPLC. 1H NMR (d6-DMSO, 400 MHz) 13.04 ppm (0.3H, s), 12.99 ppm (0.3H, s), 8.85 ppm (1H, s), 8.074 ppm (1H, s), 7.96 ppm (dd, 8.4 Hz, 1.2 Hz), 7.55 ppm (d, 8.4 Hz). MS: (Electrospray+) 201.8 m/z (M+), 223.7 m/z (M+Na).

Workup

filtrationthe brown solid filtered
washwashed with water
customThe material was dried

Sources & evidence

ORD record: ord-06b8827d9a7b458a9f6bf5b7794d7dd6
Source dataset: uspto-grants-2015_09
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US09144757B2

Reaction notes

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