syn-anti-Isomerism at the Carbon-Sulfur Double Bond in Isothiouronium Salts
✍ Scribed by Priv.-Doz. Dr. Horst Kessler; Hans-Otto Kalinowski
- Publisher
- John Wiley and Sons
- Year
- 1970
- Tongue
- English
- Weight
- 218 KB
- Volume
- 9
- Category
- Article
- ISSN
- 0044-8249
No coin nor oath required. For personal study only.
✦ Synopsis
respectively, in about 50 yield by reaction with di(p-nitrophenyl) phosphorochloridate 151.
Whereas (56) is obtained directly (55 % yield) on treatment of (26) with 1 N NaOH/methanol (1 :1) in 100 h at room temperature, (5a) can only be synthesized stepwise. As first step, one p-nitrophenol group is removed by ammonia/pyridine'water ( 5 : 2: 1); (3) is isolated in 80 % yield by preparative layer chromatography and cyclized according to Borden [61 by treatment with 1 M potassium tert-butoxideltertbutanol in dimethyl sulfoxide (15 min, 10°C) to give the cyclophosphate analog (5a) which is isolated in 65 % yield after separation o n a DEAE cellulose column. Ring closure of (2b) to (5b) proceeds via the unusual cyclic diester amide: after 1 h it was possible to isolate compound ( 4 ) .
All the compounds gave correct analyses and spectroscopic data. Compounds (5a) and (5b) are currently being tested in conjunction with other research teams for biological activity.