โ Scribed by Prof. H. J. Teuber; K.-H. Dietz
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residue remaining on evaporation was chromatographed on 850 g of silica gel (column 4x90 cm) with hexane/acetone (100: 3). The first 300 ml of eluate contained 10.9 g of crude product (30). This was taken up in ether, and washed with 1 % hydrochloric acid and 1 % sodium hydrogen carbonate solution; the ethereal solution was dried, evaporated, and distilled. After a forerun of b.p. 35-103 "Cj0.l mm, 3.8 g of product (3a) was obtained.
(36) + ( 5 6 ) . 3.6 g (0.015 mole) of compound (36) and 2.9 g (0.015 mole) of perphthalic acid in 32 ml of ether were kept at -5 'C for 2 hr. The solution was then washed several times with 1 % sodium hydrogen carbonate solution, dried, and evaporated. The 2.1 g of residue crystallized when scratched. When recrystallized twice from petroleum ether, the product (Sb) (1.8 g) was identical (m.p., mixed m.p., 1R spectra) with that obtained from p-aminobenzenesulfinyl chloride and dimethylbutadiene (20 hr, 70 "C, 68 %).
๐ SIMILAR VOLUMES
The IR spectra of compounds ( ) and ( 6 ) contain pronounced bands at 2260 cm-1, 1640 cm-1, and 1770 cm-1, which indicate the presence of N=C=O, C=N, and a halogenoformyl group. The spectra show that compound (2a) exists wholly in the isocyanate form, but that (2d) exists almost wholly in the N-(chl