Preparation of the Bisthiomalonic Acids la-c.-In a 250-m1 round-bottom flask equipped with gas inlet and outlet tubes, pressure-equalizing funnel, ice bath, and magnetic stirrer was placed 36 g of anhydrous pyridine. The pyridine was saturated with hydrogen sulfide for 30 min; then a solution of 0.05 mol of the appropriate disubstituted malonyl chloride in 20 ml of anhydrous ether was added oiu the dropping funnel over a period of 2-3 hr (bath ...