2-Propanesulfinic acid,2-methyl- synthesis

13synthesis methods

Product Name:2-Propanesulfinic acid,2-methyl-
CAS Number:29099-08-9
Molecular formula:C4H10O2S
Molecular Weight:122.19

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Yield: 88%

Reaction Conditions:

with 3-chloro-benzenecarboperoxoic acid in dichloromethane at -78; for 10 h;

Steps:

33 4.2.33 2-Methylpropane sulfinamide
A solution of 2-methylpropanethiol (14.1cm³, 125mmol) in DCM (50mL) was cooled to -40°C and at 30min intervals, a slurry (50mL) of a suspension of m-chloroperbenzoic acid (63.2g, 256mmol, 2.05equiv) in DCM (500mL) cooled to -78°C was added in portions with vigorous stirring (exothermic reaction) over 10h. The resulting white suspension was stirred at -30°C overnight, then cooled to -78°C and filtered. The filtrate was concentrated under reduced pressure then dried under high vacuum to provide crude tert-butanesulfinic acid (13.5g, 88%). Thionyl chloride (40.3mL, 552.5mmol, 5equiv). was added to this sulfinic acid at -40°C under nitrogen and the yellow solution was allowed to warm to rt and was stirred for 2h. Concentration under high vacuum gave tert-butylsulfinyl chloride (12.9g, 83%) as a brown oil. This sulfinyl chloride in DCM (582mL) was added to aqueous ammonia (38% in water 582mL, 220mmol, 2.4equiv) and the mixture stirred at rt for 1h. The aqueous layer was then saturated with NaCl and extracted with DCM (4×600cm³). The organic extracts were dried (MgSO₄) and concentrated under reduced pressure to yield the title compound (9.2g, 83%) as a white solid crystallised from hexane. R_f=0.23 (EtOAc); mp 103-104°C [lit.¹⁴ for the (S)-enantiomer 106°C (TCI)]; ν_max/cm^-1 3231, 2979, 2959, 2928, 2869, 1677, 1570, 1475, 1461, 1364, 1309, 1193, 1132, 1030 and 893; δ_H (300MHz, CDCl₃) 1.19 [9H, s, C(CH₃)₃] and 3.96 (2H, br s, NH₂); δ_C (75MHz, CDCl₃) 22.1 and 55.2; m/z (CI+) 139 (M⁺+18, 100%) and 122 (M⁺+1, 100).