Bromide ion → Pseudourea, 2-(p-nitrobenzyl)-2-thio-, monohydrobromide

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Reaction Steps

Thiourea (8c) (1.55 kg) and acetone (30 L) were added to a 72-L reactor under a nitrogen atmosphere. The mixture was agitated. 4-nitrophenylmethyl bromide (8d) (4.00 kg) and acetone (15 L) were added to a separate flask. The mixture was stirred until the bromide dissolved (warming may be required). The solution of the bromide was added to the mixture of thiourea, keeping the temperature below 40° C. A thick solution formed within 30 minutes. After stiffing for 2 h, HPLC analysis of the mixture shows >99% conversion. The mixture was filtered, and the filter cake was rinsed with a 1:1 MTBE: acetone solution (8 L). The solids were dried to give 5.09 kg (93% yield) of the desired product (8a) as a white solid.

Provenance & Evidence