To a suspension of 100 g finely powdered anhydrous K₂CO₃ in 400 mL acetone containing 50 g methyl iodide there was added 41 g 5-hydroxy-1,3-benzoxathiol-2-one, and the mixture stirred overnight at room temperature. The solids were removed by filtration, and the solvent removed under vacuum. The residue was distilled to give a fraction subliming over as a solid at an oven temperature of 110 °C at 0.1 mm/Hg. This was a yellowish solid, weighing 27.4 g and having a mp of 66–72 °C. Recrystallization from MeOH gave 5-methoxy-1,3-benzoxathiol-2-one as a white solid with a mp of 75.5–76.5 °C.

To a solution of 30 g 85% KOH in 75 mL warm H₂O, there was added an equal volume of warm MeOH followed by 16 g 5-methoxy-1,3-benzoxathiol-2-one, and the mixture was held under reflux conditions for 2 h. After cooling to room temperature, the mix was acidified with HCl and extracted with 2×100 mL CH₂Cl₂. Removal of the solvent from the pooled extracts gave a yellow oil that crystallized on standing. The product, 2-mercapto-4-methoxyphenol, weighed 14 g and had a mp of 56–57 °C.

A solution of 10 g 2-mercapto-4-methoxyphenol in 100 mL MEK was added over the course of 1 h to a vigorously stirred suspension of 25 g finely powdered anhydrous K₂CO₃ in 200 mL MEK that contained 14 g methylene bromide. The reflux was maintained for 48 h. After cooling, the mixture was freed of solids by filtration and the filter cake washed with 50 mL additional MEK. The combined washes and filtrate were stripped of solvent under vacuum, and the product distilled to give 3.3 g of 5-methoxy-1,3-benzoxathiol as a yellowing oil that had a bp of 110–120 °C at 1.7 mm/Hg. There was considerable residue in the pot, which was discarded. The NMR spectrum was excellent, with the methylene protons a two-hydrogen singlet at 5.6 ppm.

To a mixture of 3.2 g POCl₃ and 2.8 g N-methylformanilide that had been heated briefly on the steam bath (to the formation of a deep claret color) there was added 2.3 g 5-methoxy-1,3-benzoxathiol, and steam bath heating was continued for an additional 5 min. The reaction mixture was poured into 100 mL H₂O, and after a few minutes stirring, the insolubles changed to a loose solid. This was collected by filtration, H₂O washed and, after sucking as dry as possible, recrystallized from 30 mL boiling MeOH. This provided 1.9 g of 6-formyl-5-methoxy-1,3-benzoxathiol as brownish needles that melted at 119–120 °C.

A solution of 1.5 g 6-formyl-5-methoxy-1,3-benzoxathiol in 50 mL nitroethane was treated with 0.3 g anhydrous ammonium acetate and heated on the steam bath for 5 h. Removal of the solvent under vacuum gave a residue that crystallized. This was recrystallized from 110 mL boiling EtOH providing, after filtering and air drying, 1.3 g 5-methoxy-6-(2-nitro-1-propenyl)-1,3-benzoxathiol as San Francisco Giants-orange-colored crystals.

A solution of AH was prepared by the treatment of a solution of 1.3 g LAH in 10 mL THF, at 0 °C and under He, with 0.8 mL 100% H₂SO₄. A solution of 1.1 g of 5-methoxy-6-(2-nitro-1-propenyl)-1,3-benzoxathiol in 25 mL THF was added dropwise, and the stirring was continued for 1 h. After a brief period at reflux, the reaction mixture was returned to room temperature, and the excess hydride destroyed by the addition of IPA. The salts were converted to a filterable mass by the addition of 5% NaOH and, after filtering and washing with IPA, the combined filtrate and washings were stripped of solvent under vacuum. The residue was dissolved in dilute H₂SO₄ which was washed with 3×75 mL CH₂Cl₂ and then, after being made basic with 25% NaOH, the product was extracted with 2×75 mL CH₂Cl₂. The extracts were pooled, and the solvent removed under vacuum. Distillation of the residue gave a fraction that boiled at 140–155 °C at 0.3 mm/Hg which weighed 0.7 g. This was dissolved in 4 mL IPA, neutralized with 14 drops of concentrated HCl, heated to effect complete solution, then diluted with 10 mL of anhydrous Et₂O. The white crystals that formed were removed, Et₂O washed, and air dried to give 0.6 g 6-(2-aminopropyl)-5-methoxy-1,3-benzoxathiol hydrochloride (4T-MMDA-2).

The positional isomer of the heterocyclic carbonate used here is also known. Instead of using benzoquinone as a starting material with thiourea as the sulfur source (giving the 1,4- oxygen orientation), one can start with resorcinol in reaction with ammonium thiocyanate as the sulfur source (in the presence of copper sulfate) and get the positional isomer with a 1,3- oxygen orientation. This material (also known as thioxolone, or tioxolone, or 6-hydroxy-1,3-benzoxathiol-2-one, and which is commercially available) should follow the same chemistry shown here for the 5-hydroxy analogue, and give 5T-MMDA-2 (5-(2-aminopropyl)-6-methoxy-1,3-benzoxathiole or 2-methoxy-5,4-methylenethiooxyamphetamine) as a final product. I would guess, based on the findings that compare with , that this would be a relatively low-potency compound. At least it should be an easy one to make!