Хлорирование 2С-Н по Шульгину.

Из ПиХКАЛ.

The free base of 2,5-dimethoxyphenethylamine was generated from its salt (see recipe for 2C-H for the preparation of this compound) by treating a solution of 16.2 g of the hydrochloride salt in 300 mL H2O with aqueous NaOH, extraction with 3x75 mL CH2Cl2, and removal of the solvent from the pooled extracts under vacuum. The colorless residue was dissolved in 75 mL glacial acetic acid (the solids that initially formed redissolved completely) and this was cooled to 0 deg C with an external ice bath. With vigorous stirring, there was added 4.0 mL of liquid chlorine, a little bit at a time with a Pasteur pipette. The theoretical volume was 3.4 mL, but some was lost in pipetting, some on contact with the 0 deg C acetic acid, and some was lost by chlorination of the acetic acid. The reaction turned a dark amber color, was allowed to stir for an additional 10 min, then quenched with 400 mL H2O. This was washed with 3x100 mL CH2Cl2 (which removed some of the color) then brought to neutrality with dilute aqueous NaOH and treated with a small amount of sodium dithionite which discharged most of the color (from deep brown to pale yellow). The reaction was made strongly basic with aqueous KOH, and extracted with 3x75 mL CH2Cl2. The pooled extracts were washed once with H2O and the solvent was removed under vacuum leaving about 10 mL of a deep amber oil as residue. This was dissolved in 75 mL IPA and neutralized with concentrated HCl which allowed spontaneous crystallization. These crystals were removed by filtration, washed with an additional 20 mL IPA, and air-dried to constant weight. There was thus obtained 4.2 g 2,5-dimethoxy-4-chlorophenethylamine hydrochloride (2C-C) with a mp of 218-221 deg C. Recrystallization from IPA increased this to 220-222 deg C. The position of chlorination on the aromatic ring was verified by the presence of two para-protons in the NMR, at 7.12 and 7.20 ppm from external TMS, in a D2O solution of the hydrochloride salt.

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